Editor's Choice Articles

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to authors, or important in this field. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

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Editorial

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Editorial
Consumption and Production Patterns for Agricultural Sustainable Development
Agronomy 2021, 11(5), 814; https://doi.org/10.3390/agronomy11050814 - 21 Apr 2021
Abstract
Agriculture has always played a key role in feeding the world population and ensuring the development of sustainable food production systems [...] Full article
Editorial
Towards Sustainable Intensification of Crop Production—Yield Gaps and Water Use Efficiency in Farming Systems
Agronomy 2021, 11(4), 710; https://doi.org/10.3390/agronomy11040710 - 08 Apr 2021
Abstract
The primary objective of any cropping system continues to be increasing the productivity and profitability of crops [...] Full article
Editorial
Application of Plant Growth Promoting Microorganism and Plant Growth Regulators in Agricultural Production and Research
Agronomy 2021, 11(3), 524; https://doi.org/10.3390/agronomy11030524 - 11 Mar 2021
Abstract
Plant growth-promoting microorganisms (PGPM) are rhizosphere microorganisms that colonize the root environment [...] Full article
Editorial
Special Issue “Genetics, Genomics, and Breeding of Legume Crops”
Agronomy 2021, 11(3), 475; https://doi.org/10.3390/agronomy11030475 - 04 Mar 2021
Abstract
Legume crops are grown in the world primarily for their grain seeds that are widely used for human and animal consumption or for the production of oils for industrial uses [...] Full article
(This article belongs to the Special Issue Genetics, Genomics, and Breeding of Legume Crops)
Editorial
Extraction and Analysis of Natural Product in Plant
Agronomy 2021, 11(3), 415; https://doi.org/10.3390/agronomy11030415 - 25 Feb 2021
Abstract
Plants are well known for being a major source of natural compounds, many of them generally considered of biological interest for their antioxidant, anti-inflammatory, antimicrobial or anti-cancerogenic properties [...] Full article
(This article belongs to the Special Issue Extraction and Analysis of Natural Product in Plant)
Editorial
Bioenergy Crops: Current Status and Future Prospects
Agronomy 2021, 11(2), 316; https://doi.org/10.3390/agronomy11020316 - 11 Feb 2021
Abstract
Biomass always played a crucial role as an energy source during the evolution of humankind and our technical development [...] Full article
(This article belongs to the Special Issue Bioenergy Crops: Current Status and Future Prospects)
Editorial
Climate Change: A New Challenge for the Winemaking Sector
Agronomy 2020, 10(10), 1465; https://doi.org/10.3390/agronomy10101465 - 25 Sep 2020
Cited by 3
Abstract
Viticulture and winemaking have a strong socio-economic importance worldwide. Weather and climate represent key forcing factors for grapevine development, yields, and quality. Hence, climate change is expected to pose a strong impact on this crop, threatening the sustainability of the winemaking sector. Recent-past [...] Read more.
Viticulture and winemaking have a strong socio-economic importance worldwide. Weather and climate represent key forcing factors for grapevine development, yields, and quality. Hence, climate change is expected to pose a strong impact on this crop, threatening the sustainability of the winemaking sector. Recent-past trends show noticeable warming in the grapevine growing season, as well as changes in the precipitation patterns in many renowned winemaking regions worldwide. Furthermore, climate projections point to enhanced stress conditions for grapevine growth under future scenarios. The strong evidence for a significant warming and drying in the upcoming decades urges adaptation measures to be taken by the winemaking sector. The aim of this editorial is to provide an updated overview of the adaptation measures that can be used by sector stakeholders to mitigate the negative impacts of climate change. A recent review article, which highlights several adaptation strategies to ensure the future sustainability of this important sector, is hereby analyzed. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
Editorial
Toward a Sustainable Agriculture Through Plant Biostimulants: From Experimental Data to Practical Applications
Agronomy 2020, 10(10), 1461; https://doi.org/10.3390/agronomy10101461 - 24 Sep 2020
Cited by 10
Abstract
Modern agriculture increasingly demands an alternative to synthetic chemicals (fertilizers and pesticides) in order to respond to the changes in international law and regulations, but also consumers’ needs for food without potentially toxic residues. Microbial (arbuscular mycorrhizal and plant growth promoting rhizobacteria: Azotobacter [...] Read more.
Modern agriculture increasingly demands an alternative to synthetic chemicals (fertilizers and pesticides) in order to respond to the changes in international law and regulations, but also consumers’ needs for food without potentially toxic residues. Microbial (arbuscular mycorrhizal and plant growth promoting rhizobacteria: Azotobacter, Azospirillum and Rizhobium spp.) and non-microbial (humic substances, silicon, animal- and vegetal-based protein hydrolysate and macro- and micro-algal extracts) biostimulants represent a sustainable and effective alternative or complement for their synthetic counterparts, bringing benefits to the environment, biodiversity, human health and economy. The Special Issue “Toward a sustainable agriculture through plant biostimulants: from experimental data to practical applications” compiles 34 original research articles, 4 review papers and 1 brief report covering the implications of microbial and non-microbial biostimulants for improving seedling growth and crop performance, nutrient use efficiency and quality of the produce as well as enhancing the tolerance/resistance to a wide range of abiotic stresses in particular salinity, drought, nutrient deficiency and high temperature. The present compilation of high standard scientific papers on principles and practices of plant biostimulants will foster knowledge transfer among researchers, fertilizer and biostimulant industries, stakeholders, extension specialists and farmers, and it will enable a better understanding of the physiological and molecular mechanisms and application procedure of biostimulants in different cropping systems. Full article
Editorial
Microalgae: New Source of Plant Biostimulants
Agronomy 2020, 10(9), 1240; https://doi.org/10.3390/agronomy10091240 - 22 Aug 2020
Cited by 6
Abstract
Biostimulant manufacturers have developed innovative products targeting specific agronomic needs, hence attracting the attention of the scientific community, extension specialists, and industry stakeholders including policymakers and crop producers. Microalgae acquire a broad economic value in the production of nutrient dense food and supplementary [...] Read more.
Biostimulant manufacturers have developed innovative products targeting specific agronomic needs, hence attracting the attention of the scientific community, extension specialists, and industry stakeholders including policymakers and crop producers. Microalgae acquire a broad economic value in the production of nutrient dense food and supplementary diet produce, in addition to their high importance in biofuel production and wastewater bioremediation. Recently, microalgae, which comprise blue-green algae (eukaryotic and prokaryotic cyanobacteria), have gained prominence as biostimulant products due to their potential to increase germination, seedling growth, plant growth, productivity, nutrient use efficiency, as well as tolerance to a wide range of abiotic stresses (salinity, drought, sub- and supra-optimal temperatures, and heavy metals contamination). Although it is well established that green and blue-green algae produce several bioactive and signaling molecules active on horticultural and agronomic crops, their targeted applications in plant science are still in their infancy stage. The aim of this editorial paper is to provide an updated overview of this far-reaching new category of plant biostimulants and the possible physiological and molecular mechanisms behind the biostimulatory action based on the recent scientific literature. Finally, this editorial paper identifies the main bottlenecks that hamper market introduction and farmers from reaping the full benefit of microalgae-based biostimulants; it also pinpoints the future relevant areas of microalgae research to enhance the biostimulant action of microalgal extracts in agriculture. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
Editorial
Molecular Genetics, Genomics, and Biotechnology in Crop Plant Breeding
Agronomy 2020, 10(3), 439; https://doi.org/10.3390/agronomy10030439 - 23 Mar 2020
Cited by 1
Abstract
A diverse set of molecular markers techniques have been developed over the last almost 40 years and used with success for breeding a number of major crops. These have been narrowed down to a few preferred DNA based marker types, and emphasis is [...] Read more.
A diverse set of molecular markers techniques have been developed over the last almost 40 years and used with success for breeding a number of major crops. These have been narrowed down to a few preferred DNA based marker types, and emphasis is now on adapting the technologies to a wide range of crop plants and trees. In this Special Issue, the strength of molecular breeding is revealed through research and review papers that use a combination of molecular markers with other classic breeding techniques to obtain quality improvement of the crop. The constant improvement and maintenance of quality by breeding is crucial and challenged by a changing climate and molecular markers can support the direct introgression of traits into elite breeding lines. All the papers in this Special Issue “Molecular genetics, Genomics, and Biotechnology in Crop Plant Breeding” have attracted significant attention, as can be witnessed by the graphs for each paper on the Journal’s homepage. It is the hope that it will encourage others to use these tools in developing an even wider range of crop plants and trees. Full article
Editorial
Viticulture and Winemaking under Climate Change
Agronomy 2019, 9(12), 783; https://doi.org/10.3390/agronomy9120783 - 21 Nov 2019
Cited by 9
Abstract
The importance of viticulture and the winemaking socio-economic sector is acknowledged worldwide. The most renowned winemaking regions show very specific environmental characteristics, where climate usually plays a central role. Considering the strong influence of weather and climatic factors on grapevine yields and berry [...] Read more.
The importance of viticulture and the winemaking socio-economic sector is acknowledged worldwide. The most renowned winemaking regions show very specific environmental characteristics, where climate usually plays a central role. Considering the strong influence of weather and climatic factors on grapevine yields and berry quality attributes, climate change may indeed significantly impact this crop. Recent-past trends already point to a pronounced increase in the growing season mean temperatures, as well as changes in the precipitation regimes, which has been influencing wine typicity across some of the most renowned winemaking regions worldwide. Moreover, several climate scenarios give evidence of enhanced stress conditions for grapevine growth until the end of the century. Although grapevines have a high resilience, the clear evidence for significant climate change in the upcoming decades urges adaptation and mitigation measures to be taken by the sector stakeholders. To provide hints on the abovementioned issues, we have edited a special issue entitled: “Viticulture and Winemaking under Climate Change”. Contributions from different fields were considered, including crop and climate modeling, and potential adaptation measures against these threats. The current special issue allows the expansion of the scientific knowledge of these particular fields of research, also providing a path for future research. Full article
(This article belongs to the Special Issue Viticulture and Winemaking under Climate Change)
Editorial
Crop Evapotranspiration
Agronomy 2019, 9(10), 614; https://doi.org/10.3390/agronomy9100614 - 05 Oct 2019
Cited by 6
Abstract
Evapotranspiration (ET) is one of the largest components of the water cycle, and accurately measuring and modeling ET is critical for improving and optimizing agricultural water management. However, parameterizing ET in croplands can be challenging due to the wide variety of irrigation strategies [...] Read more.
Evapotranspiration (ET) is one of the largest components of the water cycle, and accurately measuring and modeling ET is critical for improving and optimizing agricultural water management. However, parameterizing ET in croplands can be challenging due to the wide variety of irrigation strategies and techniques, crop varieties, and management approaches that employ traditional tabular ET and make crop coefficient approaches obsolete. This special issue of Agronomy highlights nine approaches to improve the measurement and modeling of ET across a range of spatial and temporal resolutions and differing environments that address some of the challenges encountered. Full article
(This article belongs to the Special Issue Crop Evapotranspiration)
Editorial
Deep Learning Techniques for Agronomy Applications
Agronomy 2019, 9(3), 142; https://doi.org/10.3390/agronomy9030142 - 20 Mar 2019
Cited by 13
Abstract
This editorial introduces the Special Issue, entitled “Deep Learning (DL) Techniques for Agronomy Applications”, of Agronomy. Topics covered in this issue include three main parts: (I) DL-based image recognition techniques for agronomy applications, (II) DL-based time series data analysis techniques for agronomy applications, [...] Read more.
This editorial introduces the Special Issue, entitled “Deep Learning (DL) Techniques for Agronomy Applications”, of Agronomy. Topics covered in this issue include three main parts: (I) DL-based image recognition techniques for agronomy applications, (II) DL-based time series data analysis techniques for agronomy applications, and (III) behavior and strategy analysis for agronomy applications. Three papers on DL-based image recognition techniques for agronomy applications are as follows: (1) “Automatic segmentation and counting of aphid nymphs on leaves using convolutional neural networks,” by Chen et al.; (2) “Estimating body condition score in dairy cows from depth images using convolutional neural networks, transfer learning, and model ensembling techniques,” by Alvarez et al.; and (3) “Development of a mushroom growth measurement system applying deep learning for image recognition,” by Lu et al. One paper on DL-based time series data analysis techniques for agronomy applications is as follows: “LSTM neural network based forecasting model for wheat production in Pakistan,” by Haider et al. One paper on behavior and strategy analysis for agronomy applications is as follows: “Research into the E-learning model of agriculture technology companies: analysis by deep learning,” by Lin et al. Full article
(This article belongs to the Special Issue Deep Learning Techniques for Agronomy Applications)
Editorial
Biotic and Abiotic Stress Responses in Crop Plants
Agronomy 2018, 8(11), 267; https://doi.org/10.3390/agronomy8110267 - 19 Nov 2018
Cited by 24
Abstract
Agricultural productivity depends on increasingly extreme weather phenomena, and the use of germplasm that has to be continuously improved by plant breeders to become tolerant to various biotic and abiotic stresses. Molecular plant biologists try to understand the mechanisms associated with stress responses [...] Read more.
Agricultural productivity depends on increasingly extreme weather phenomena, and the use of germplasm that has to be continuously improved by plant breeders to become tolerant to various biotic and abiotic stresses. Molecular plant biologists try to understand the mechanisms associated with stress responses and provide knowledge that could be used in breeding programs. To provide a partial overview about our current understanding about molecular and physiological stress responses, and how this knowledge can be used in agriculture, we have edited a special issue on “Biotic and Abiotic Stress Responses in Crop Plants”. Contributions are from different fields including heat stress responses, stress responses during drought and salinity, as well as during flooding, and resistance and susceptibility to pathogenetic stresses and about the role of plant functional metabolites in biotic stress responses. Future research demand in particular areas of crop stress physiology is discussed, as well as the importance of translational research and investigations directly in elite crop plants and in the genetic resources available for breeding. Full article
(This article belongs to the Special Issue Biotic and Abiotic Stress Responses in Crop Plants)
Editorial
Starch Biosynthesis in Crop Plants
Agronomy 2018, 8(6), 81; https://doi.org/10.3390/agronomy8060081 - 25 May 2018
Cited by 3
Abstract
Starch is a water-insoluble polyglucan synthesized inside the plastids of plant tissues to provide a store of carbohydrate. Starch harvested from plant storage organs has probably represented the major source of calories for the human diet since before the dawn of civilization. Following [...] Read more.
Starch is a water-insoluble polyglucan synthesized inside the plastids of plant tissues to provide a store of carbohydrate. Starch harvested from plant storage organs has probably represented the major source of calories for the human diet since before the dawn of civilization. Following the advent of agriculture and the building of complex societies, humans have maintained their dependence on high-yielding domesticated starch-forming crops such as cereals to meet food demands, livestock production, and many non-food applications. The top three crops in terms of acreage are cereals, grown primarily for the harvestable storage starch in the endosperm, although many starchy tuberous crops also provide an important source of calories for various communities around the world. Despite conservation in the core structure of the starch granule, starches from different botanical sources show a high degree of variability, which is exploited in many food and non-food applications. Understanding the factors underpinning starch production and its final structure are of critical importance in guiding future crop improvement endeavours. This special issue contains reviews on these topics and is intended to be a useful resource for researchers involved in improvement of starch-storing crops. Full article
(This article belongs to the Special Issue Starch Biosynthesis in Crop Plants)
Editorial
Transdisciplinary Graduate Training in Predictive Plant Phenomics
Agronomy 2018, 8(5), 73; https://doi.org/10.3390/agronomy8050073 - 16 May 2018
Cited by 2
Abstract
Novel methods to increase crop productivity are required to meet anticipated demands for food, feed, fiber, and fuel. It is becoming feasible to use modern sensors and data analysis techniques for predicting plant growth and productivity based on genomic, phenotypic, and environmental data. [...] Read more.
Novel methods to increase crop productivity are required to meet anticipated demands for food, feed, fiber, and fuel. It is becoming feasible to use modern sensors and data analysis techniques for predicting plant growth and productivity based on genomic, phenotypic, and environmental data. To design and construct crops that deliver desired traits requires trained personnel with scientific and engineering expertise as well as a variety of “soft” skills. To address these needs at Iowa State University, we developed a graduate specialization called “Predictive Plant Phenomics” (P3). Although some of our experiences may be unique, many of the specialization’s principles are likely to be broadly applicable to others interested in developing graduate training programs in plant phenomics. P3 involves transdisciplinary training and activities designed to develop communication, teambuilding, and management skills. To support students in this demanding and unique intellectual environment, we established a two-week boot camp before their first semester and founded a community of practice to support students throughout their graduate careers. Assessments show that P3 students understand the transdisciplinary training concepts, have formed a beneficial and supportive community, and interact with diverse faculty outside of their home departments. To learn more about the P3 program, visit www.predictivephenomicsinplants.iastate.edu. Full article
(This article belongs to the Special Issue Precision Phenotyping in Plant Breeding)
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Research

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Article
Mechanism(s) of Glyphosate Resistance in a Selected Plantago lanceolata (L.) R Biotype
Agronomy 2021, 11(5), 884; https://doi.org/10.3390/agronomy11050884 - 30 Apr 2021
Abstract
In 2003, a glyphosate-resistant plantago (Plantago lanceolata L.) population located in the Robertson district of South Africa was subjected to different glyphosate dosages and the highest dosage (7200 g a.e. ha−1) gave no acceptable levels of control. Here we reconfirm [...] Read more.
In 2003, a glyphosate-resistant plantago (Plantago lanceolata L.) population located in the Robertson district of South Africa was subjected to different glyphosate dosages and the highest dosage (7200 g a.e. ha−1) gave no acceptable levels of control. Here we reconfirm resistance and investigate the mechanism of glyphosate resistance. Dose-response curves indicated that the glyphosate dosage rate causing 50% survival (LD50) for the resistant (R) biotype is 43 times greater than for the susceptible (S) biotype, i.e., 43-fold resistant to glyphosate. Investigation into the molecular mechanism of plantago showed shikimate accumulation of the R biotype was lower than that of the S biotype. The reported 31P and 13C nuclear magnetic resonance (NMR) spectra show rapid glyphosate translocation into the young untreated leaves of the S biotype. No glyphosate translocation was observed in the R biotype. A point mutation in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene, resulting in an amino acid substitution was also observed, indicating two unique glyphosate resistance mechanisms within the R biotype. The rapid evolution of glyphosate-resistant weeds threatens the usage of the world’s most important herbicide (glyphosate), which is essential in world food production and further limits grower options for weed control. New weed management strategies will be necessary to combat plantago R biotypes. Full article
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Article
Effect of the Degree of Soil Contamination with Heavy Metals on Their Mobility in the Soil Profile in a Microplot Experiment
Agronomy 2021, 11(5), 878; https://doi.org/10.3390/agronomy11050878 - 29 Apr 2021
Abstract
Adjusting Polish law to EU standards, many studies were started in the 1990s on the harmfulness of presumably contaminating elements (PCE) to the environment and the quality of plants intended produced for food purposes. For this reason, in 1987, a unique microplate experiment [...] Read more.
Adjusting Polish law to EU standards, many studies were started in the 1990s on the harmfulness of presumably contaminating elements (PCE) to the environment and the quality of plants intended produced for food purposes. For this reason, in 1987, a unique microplate experiment was established on natural soils artificially contaminated with copper, zinc, lead and cadmium oxides (up to the pollution level of class I, II and III). The soils were diversified in terms of pH (through liming), organic matter content (through the addition of brown coal) and the grain size composition of the humus level (Ap) (strong clay sand and light silt clay). After 14 years from the introduction of different rates of metals into the top layer (0–30 cm) of the two soils studied, relatively large movement of heavy metals in the soil profile occurred. The amount of leached metals depended mainly on the rate of a given element. The more contaminated was the soil was, the heavier the metals that leached to lower genetic levels of soil. Contaminated soils always had a higher concentration of individual metals in Et than in Bt level. The content of the tested metals in the Et layer was determined in HCl (1 mol·dm−3) and compared to the humus level. Only at the soil depth below 50 cm (Bt), the content of the studied metals’ forms was much lower than in the surface levels. The calculated mobility coefficients of the tested metals determined in 1 M HCl indicate a larger movement of the tested metals in lighter soils than in medium soils. The highest displacement coefficients were obtained for cadmium, while the lowest were for lead. An increase in mobility was obtained alongside an increase in soil contamination with the heavy metals studied. By analyzing the mobility coefficients (heavy metal increase in the Bt and Et layers), they can be ranked in the following decreasing sequence: on light soils: Cd > Cu > Zn > Pb and on medium soils: Cd > Zn > Pb > Cu. Full article
(This article belongs to the Special Issue Heavy Metal Pollution and Its Effects on Agriculture)
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Article
Confounding Factors in Container-Based Drought Tolerance Assessments in Solanum tuberosum
Agronomy 2021, 11(5), 865; https://doi.org/10.3390/agronomy11050865 - 28 Apr 2021
Abstract
Potato is an important food crop with high water-use-efficiency but low drought tolerance. The bottleneck in drought tolerance breeding is phenotyping in managed field environments. Fundamental research on drought tolerance is predominantly done in container-based test systems in controlled environments. However, the portability [...] Read more.
Potato is an important food crop with high water-use-efficiency but low drought tolerance. The bottleneck in drought tolerance breeding is phenotyping in managed field environments. Fundamental research on drought tolerance is predominantly done in container-based test systems in controlled environments. However, the portability of results from these systems to performance under field conditions is debated. Thus, we analyzed the effects of climate conditions, container size, starting material, and substrate on yield and drought tolerance assessment of potato genotypes compared to field trials. A leave one out assessment indicated a minimum of three field trials for stable tolerance prediction. The tolerance ranking was highly reproducible under controlled-conditions, but weakly correlated with field performance. Changing to variable climate conditions, increasing container size, and substituting cuttings by seed tubers did not improve the correlation. Substituting horticultural substrate by sandy soil resulted in yield and tuber size distributions similar to those under field conditions. However, as the effect of the treatment × genotype × substrate interaction on yield was low, drought tolerance indices that depend on relative yields can be assessed on horticultural substrate also. Realistic estimates of tuber yield and tuber size distribution, however, require the use of soil-based substrates. Full article
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Article
Optimizing Biocontrol Activity of Paenibacillus xylanexedens for Management of Hairy Root Disease in Tomato Grown in Hydroponic Greenhouses
Agronomy 2021, 11(5), 817; https://doi.org/10.3390/agronomy11050817 - 21 Apr 2021
Abstract
Hairy root disease (HRD) caused by rhizogenic Agrobacterium biovar 1 strains affect tomato, cucumber, eggplant, and bell pepper grown in hydroponic greenhouses and can cause considerable yield losses worldwide. Recently, Paenibacillus xylanexedens strains (ST15.15/027 and AD117) with antagonistic activity against rhizogenic agrobacteria were [...] Read more.
Hairy root disease (HRD) caused by rhizogenic Agrobacterium biovar 1 strains affect tomato, cucumber, eggplant, and bell pepper grown in hydroponic greenhouses and can cause considerable yield losses worldwide. Recently, Paenibacillus xylanexedens strains (ST15.15/027 and AD117) with antagonistic activity against rhizogenic agrobacteria were identified. In this study, we present results of greenhouse trials of two consecutive growing seasons (2019 and 2020) to examine the potential of these two biocontrol organisms (BCOs) under practical conditions. BCO-treatment at a 107 colony forming units (CFU)/mL density resulted in a considerable reduction of the HRD infestation rate, confirming the biocontrol potential of the two P. xylanexedens strains. Results revealed that a single BCO strain (ST15.15/027) performed equally well as the mixed inoculum of both strains. The same level of biocontrol activity was even achieved when the BCO inoculum density was reduced to 105 CFU/mL. qPCR analysis further showed that Paenibacillus was still present in rockwool substrate near the end of both trials, indicating that they persist well in a rockwool environment and that application at the start of the trial is sufficient to protect tomato plants until the end of the trial. Altogether, these results are highly valuable for further optimization and exploitation of P. xylanexedens as a biocontrol product for the control of HRD in hydroponic greenhouses. Full article
(This article belongs to the Special Issue Plant Root Diseases and Integrated Pest Management)
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Article
Fusarium Head Blight and Associated Mycotoxins in Grains and Straw of Barley: Influence of Agricultural Practices
Agronomy 2021, 11(4), 801; https://doi.org/10.3390/agronomy11040801 - 19 Apr 2021
Abstract
Fusarium head blight (FHB) is a devastating fungal disease of small-grain cereals that causes significant yield losses and mycotoxin contamination, diminishing food and feed safety worldwide. In contrast to wheat, little is known about the agricultural practices that influence FHB and Fusarium mycotoxins [...] Read more.
Fusarium head blight (FHB) is a devastating fungal disease of small-grain cereals that causes significant yield losses and mycotoxin contamination, diminishing food and feed safety worldwide. In contrast to wheat, little is known about the agricultural practices that influence FHB and Fusarium mycotoxins in barley. Thus, a nationwide survey was conducted across Switzerland for harvest samples in 2016 and 2017, accompanied with a questionnaire to obtain information about the agricultural practices in each barley field. In total, 253 grain and 237 straw samples were analyzed. In both years, F. graminearum was the predominant Fusarium species in grains followed by F. avenaceum and F. poae. Growing maize before barley was associated with increased amount of F. graminearum DNA in grains and straw as well as with elevated concentrations of deoxynivalenol in grains of barley. On the other hand, growing pasture before barley resulted in increased incidence of F. poae and concentration of numerous mycotoxins in grains (e.g., enniatins) and straw (e.g., beauvericin). Reduced tillage practices were linked to increased incidence of F. graminearum and deoxynivalenol content in grains and straw. In contrast, conventional tillage was linked to higher incidence of F. poae. Moreover, use of spring barley was associated with decreased amount of F. graminearum DNA in grains and straw, but increased incidence of F. poae and F. avenaceum. Use of the spring variety Eunova was linked to increased concentrations of several Fusarium mycotoxins in grains (e.g., enniatins and nivalenol). Furthermore, the application of strobilurin-based fungicides was associated with higher deoxynivalenol and beauvericin contents in grains. The application of plant growth regulators was associated with increased concentration of some Fusarium mycotoxins in grains (e.g., culmorin), while absence of growth regulators application was linked to elevated concentration of some other mycotoxins (e.g., nivalenol). We conclude that individual agricultural practices can suppress some FHB causing species and reduce the associated mycotoxins, but can promote others. Hence, integrated control measures combining numerous prevention and intervention strategies should be applied for the sustainable management of mycotoxins in barley. Full article
(This article belongs to the Special Issue Strategies for the Control of Fusarium Head Blight in Cereals)
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Article
Supplementation of Organic Amendments Improve Yield and Adaptability by Reducing the Toxic Effect of Copper in Cocksfoot Grass (Dactylis glomerata L. Cv Amera)
Agronomy 2021, 11(4), 791; https://doi.org/10.3390/agronomy11040791 - 16 Apr 2021
Abstract
Copper is an element necessary for the proper growth and development of plants, but when taken in excess amounts, it can be toxic. Its availability for plant can be reduced by using organic fertilizers or soil liming. The aim of the study was [...] Read more.
Copper is an element necessary for the proper growth and development of plants, but when taken in excess amounts, it can be toxic. Its availability for plant can be reduced by using organic fertilizers or soil liming. The aim of the study was to investigate the effect of increasing doses of copper (100, 200, and 300 mg Cu·kg−1 of soil) application in combination with various organic amendments (cattle manure, chicken manure, and spent mushroom substrate) on the yield of cocksfoot and its content and uptake of this metal, and to determine its coefficient of bioaccumulation and tolerance indices. The toxic effect of copper manifested by significant decrease in the yield of the test plant was after the application of 300 mg·kg−1 of soil. Increasing doses of copper application increased its content and uptake by the test plant, while observing the decreasing bioaccumulation factor. All the soil amendments reduced the toxic effect of copper on cocksfoot. The most effective organic amendment in terms of yield and protective effects against high levels of copper was cattle manure, in the case of which the Org/Cu and Cu/Org tolerance indices were highest. Full article
(This article belongs to the Special Issue Heavy Metal Pollution and Its Effects on Agriculture)
Article
Nozzle Selection and Adjuvant Impact on the Efficacy of Glyphosate and PPO-Inhibiting Herbicide Tank-Mixtures
Agronomy 2021, 11(4), 754; https://doi.org/10.3390/agronomy11040754 - 13 Apr 2021
Abstract
PPO-inhibiting herbicides in combination with glyphosate for postemergence applications is a common approach to manage glyphosate- and ALS-inhibitor-resistant weeds. PPO-inhibitors can reduce glyphosate translocation when applied in tank-mixtures, but adjuvants may be used to overcome this effect. Additionally, optimal droplet size may be [...] Read more.
PPO-inhibiting herbicides in combination with glyphosate for postemergence applications is a common approach to manage glyphosate- and ALS-inhibitor-resistant weeds. PPO-inhibitors can reduce glyphosate translocation when applied in tank-mixtures, but adjuvants may be used to overcome this effect. Additionally, optimal droplet size may be affected by tank-mixtures of different herbicides and it can be crucial to herbicide efficacy. Field and greenhouse studies were conducted to investigate the impact of nozzle selection and adjuvants on weed control and interactions when applying PPO-inhibitors (fomesafen or lactofen) alone or in tank-mixture with glyphosate to five weed species using six nozzle types. Ultra-coarse droplets were just as effective as medium droplets regardless of the spray solution, but have a lower likelihood of off-target movement. Tank-mixtures applied were consistently antagonistic to common lambsquarters, horseweed, and Palmer amaranth. Only fomesafen was antagonistic to kochia whereas synergistic interactions were observed when glyphosate plus lactofen were applied in combination with COC, DRA + COC, or NIS. Separate applications are advisable with herbicide- and weed-specific situations to avoid antagonism, which is necessary to achieve optimum weed control and maintain the effectiveness of PPO-inhibitors. Future research should continue to look at these important interactions across a wide range of weed species. Full article
(This article belongs to the Section Weed Science and Weed Management)
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Article
Metabonomic Profiling Analyses Reveal ANS Upregulation to Enhance the Flavonoid Pathway of Purple-Fleshed Sweet Potato Storage Root in Response to Deep Shading
Agronomy 2021, 11(4), 737; https://doi.org/10.3390/agronomy11040737 - 10 Apr 2021
Abstract
Intercropping, as a common worldwide cultivation pattern, provides opportunities for sustainable agriculture with fuller use of light, temperature and land resources and greater yield per unit of land. The intercropping impact on crop quality is a current focus. This study found that shading [...] Read more.
Intercropping, as a common worldwide cultivation pattern, provides opportunities for sustainable agriculture with fuller use of light, temperature and land resources and greater yield per unit of land. The intercropping impact on crop quality is a current focus. This study found that shading cultivation of purple-fleshed sweet potato can improve the storage root pigment accumulation by more than 20% to increase economic benefits. We performed gas chromatography and mass spectrometry analysis of storage roots of the anthocyanin-enriched cultivar Jihei-1 under 60% shading and nonshaded treatments. A total of 224 differential metabolites were identified, among which N-acetyl-5-hydroxytryptamine, 1-monopalmitin, 4-pyridoxic acid, dodecano, arbutin, tryptophan, citrulline and phenylalanine were significantly upregulated under shading with a more than 10-fold change. Furthermore, metabolic pathway enrichment maps were based on the biological processes and stratification level selected. These metabolites mainly influenced the pathways of phenylpropanoid biosynthesis, the citrate cycle, organic acid biosynthesis and metabolism and amino acid metabolism. Through tissue-specific dynamic changes in amino acids, soluble sugars, starch and anthocyanins during storage root development, we proposed a variety-specific strategy of purple-fleshed sweet potato in response to prolonged deep shading, that is, utilizing and enhancing broad aboveground-tissue photosynthesis and transferring photosynthates into roots in advance, leading to a rapid increase in storage root anthocyanin synthesis. With comprehensive qPCR, western blot and enzyme activity analyses, we identified three key enzymes, CHS, ANS and 3GT, in purple-fleshed sweet potato storage roots in response to shading, which affect the root anthocyanin content by influencing the flavonoid metabolism pathway. This study provides a theoretical basis for revealing the regulation of anthocyanin synthesis in crops and a guidance for high-quality sweet potato cultivation and nutritional improvement using shade facilities. Full article
(This article belongs to the Special Issue Study of Primary Metabolism of Plants)
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Article
Can We Use Machine Learning for Agricultural Land Suitability Assessment?
Agronomy 2021, 11(4), 703; https://doi.org/10.3390/agronomy11040703 - 07 Apr 2021
Abstract
It is vital for farmers to know if their land is suitable for the crops that they plan to grow. An increasing number of studies have used machine learning models based on land use data as an efficient means for mapping land suitability. [...] Read more.
It is vital for farmers to know if their land is suitable for the crops that they plan to grow. An increasing number of studies have used machine learning models based on land use data as an efficient means for mapping land suitability. This approach relies on the assumption that farmers grow their crops in the best-suited areas, but no studies have systematically tested this assumption. We aimed to test the assumption for specialty crops in Denmark. First, we mapped suitability for 41 specialty crops using machine learning. Then, we compared the predicted land suitabilities with the mechanistic model ECOCROP (Ecological Crop Requirements). The results showed that there was little agreement between the suitabilities based on machine learning and ECOCROP. Therefore, we argue that the methods represent different phenomena, which we label as socioeconomic suitability and ecological suitability, respectively. In most cases, machine learning predicts socioeconomic suitability, but the ambiguity of the term land suitability can lead to misinterpretation. Therefore, we highlight the need for increasing awareness of this distinction as a way forward for agricultural land suitability assessment. Full article
(This article belongs to the Special Issue Machine Learning Applications in Digital Agriculture)
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Article
Application of UV-C Irradiation to Rosa x hybrida Plants as a Tool to Minimise Macrosiphum rosae Populations
Agronomy 2021, 11(4), 702; https://doi.org/10.3390/agronomy11040702 - 07 Apr 2021
Abstract
UV-C irradiation is known to enhance plant resistance against insect pests. In the present study, we evaluated the effects of low doses of UV-C on Macrosiphum rosae infesting greenhouse rose (Rosa x hybrida) plants. The application of 2.5-kJ/m2 UV-C irradiation [...] Read more.
UV-C irradiation is known to enhance plant resistance against insect pests. In the present study, we evaluated the effects of low doses of UV-C on Macrosiphum rosae infesting greenhouse rose (Rosa x hybrida) plants. The application of 2.5-kJ/m2 UV-C irradiation on rose leaves before infestation induced anti-herbivore resistance and negatively affected the aphid fecundity. No eggs and first instar nymphs were recorded on irradiated leaves, whereas an average of 4.3 and 2.7 eggs and 6.7 and 14 first instars were recorded on vars. “Etoile Brilante” and “Arlen Francis” untreated leaves, respectively. UV-C irradiation reduced the aphid population from naturally infested rose plants by up to 58%. In a greenhouse pot trial (GPT) in 2019, UV-C irradiation minimised the initial aphid population six hours after treatment. UV-C elicited host resistance and, also, helped in aphid repulsion without killing the adult individuals. UV-C did not affect the physiological responses of rose plants. The net CO2 assimilation of the UV-C irradiated plants ranged between 10.55 and 15.21 μmol/m2. sec for “Arlen Francis” and between 10.51 and 13.75 μmol/m2. sec for “Etoile Brilante” plants. These values, with only a few exceptions, were similar to those recorded to the untreated plants. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
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Article
Protected Cultivation of Horticultural Crops in Uttarakhand: An Economic Analysis
Agronomy 2021, 11(4), 692; https://doi.org/10.3390/agronomy11040692 - 05 Apr 2021
Abstract
In recent times, with the globalization of markets, shrinking of land and climate change, food basket diversification, increase in demand for nutrient-rich food, the protected cultivation of high-value crops (HVCs) have assumed a pivotal role in augmenting higher crop productivity and profitability and [...] Read more.
In recent times, with the globalization of markets, shrinking of land and climate change, food basket diversification, increase in demand for nutrient-rich food, the protected cultivation of high-value crops (HVCs) have assumed a pivotal role in augmenting higher crop productivity and profitability and enhancing nutritional security of the growing population. In this context, a study was undertaken to analyze the impact of protected cultivation in horticultural crops in the districts of Almora and Dehradun in the Uttarakhand state. It was mainly based on primary data obtained through a primary survey and focus group discussion with the 96 farmers practicing protected cultivation by using a well-structured and pre-tested questionnaire. In economic analysis, the project analysis tools were used to assess the feasibility of the protected cultivation. The study clearly demonstrated that the cultivation of vegetables and flowers under protected cultivation is a highly profitable enterprise. However, the findings of the study indicated that the subsidy scheme needs to be continued to encourage maximum farmers to adopt protected cultivation and farmers need to be encouraged to form farmers producers organizations (FPOs), which would help them in seeking better quality of inputs and enhancing negotiating power in the market to realize maximum returns for their farm produce. Full article
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Article
Total and Hot-Water Extractable Organic Carbon and Nitrogen in Organic Soil Amendments: Their Prediction Using Portable Mid-Infrared Spectroscopy with Support Vector Machines
Agronomy 2021, 11(4), 659; https://doi.org/10.3390/agronomy11040659 - 30 Mar 2021
Abstract
Against the background of climate change mitigation, organic amendments (OA) may contribute to store carbon (C) in soils, given that the OA provide a sufficient stability and resistance to degradation. In terms of the evaluation of OA behavior in soil, total organic carbon [...] Read more.
Against the background of climate change mitigation, organic amendments (OA) may contribute to store carbon (C) in soils, given that the OA provide a sufficient stability and resistance to degradation. In terms of the evaluation of OA behavior in soil, total organic carbon (TOC), total nitrogen (TN), and the ratio of TOC to TN (CN-ratio) are important basic indicators. Hot-water extractable carbon (hwC) and nitrogen (hwN) as well as their ratios to TOC and TN are appropriate to characterize a labile pool of organic matter. As for quickly determining these properties, mid-infrared spectroscopy (MIRS) in combination with calibrations based on machine learning methods are potentially capable of analyzing various OA attributes. Recently available portable devices (pMIRS) might replace established benchtop devices (bMIRS) as they have potential for on-site measurements that would facilitate the workflow. Here, we used non-linear support vector machines (SVM) to calibrate prediction models for a heterogeneous dataset of greenwaste composts and biochar compost substrates (BCS) (n = 45) using bMIRS and pMIRS instruments on ground samples. Calibrated models for both devices were validated on separate test sets and showed similar results. Ten OA were sieved to particle size classes (psc’s) of >4 mm, 2–4 mm, 0.5–2 mm, and <0.5 mm. A universal SVM model was then developed for all OA and psc’s (n = 162) via pMIRS. Validation revealed that the models provided reliable predictions for most parameters (R2 = 0.49–0.93; ratio of performance to interquartile distance (RPIQ) = 1.19–5.70). We conclude that (i) the examined parameters are sensitive towards chemical composition of OA as well as particle size distribution and can therefore be used as indicators for labile carbon and nitrogen pools of OA, (ii) prediction models based on SVM and pMIRS are a feasible approach to predict the examined C and N pools in organic amendments and their particle size class, and (iii) pMIRS can provide valuable information for optimized application of OA on cultivated soils at low costs and efforts. Full article
(This article belongs to the Special Issue Machine Learning Applications in Digital Agriculture)
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Article
Dye-Sensitized Solar Cell (DSSC): Effects on Light Quality, Microclimate, and Growth of Orthosiphon stamineus in Tropical Climatic Condition
Agronomy 2021, 11(4), 631; https://doi.org/10.3390/agronomy11040631 - 26 Mar 2021
Abstract
The main challenge facing greenhouse designers is to achieve environment-appropriate greenhouses, especially in tropical regions. The excess radiant energy transmitted into the greenhouse predisposes plants to photo-inhibition and consequently reduces crop production. Lately, photovoltaic (PV) modules are equipped as a greenhouse rooftop to [...] Read more.
The main challenge facing greenhouse designers is to achieve environment-appropriate greenhouses, especially in tropical regions. The excess radiant energy transmitted into the greenhouse predisposes plants to photo-inhibition and consequently reduces crop production. Lately, photovoltaic (PV) modules are equipped as a greenhouse rooftop to minimize the level of irradiation and air temperature in the greenhouse, simultaneously improving its energy consumption. Nevertheless, due to the low level of irradiation, denser conventional PV internal shading would influence the cultivated crops’ growth. Thus, Dye Sensitized Solar Cell (DSSC) possesses several attractive features such as transparent, sensitive to low light levels, and various color options that render DSSC a perfect choice able to serve substantially in energy buildings. This study assessed the microclimate conditions inside the greenhouse with semi-transparent DSSC mounted on top of it, describing the Photosynthetic Photon Flux Density (PPFD) (µmol m−2 s−1), Vapor Pressure Deficit VPD (kPa), relative humidity (%), and also temperature (°C). The Overall Thermal Transfer Value (OTTV), which indicates the average thermal energy transmission rate across the external layer of a structure envelope, is also presented. The effects of colored DSSC in altering the spectral of sunlight in reference to the Orthosiphon stamineus growth responses were determined. The information of the condition of DSSC greenhouse microclimate helps to identify the information for designing PV greenhouses and to produce income from both electric power and agronomic activity. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
A Pesticide Biopurification System: A Source of Biosurfactant-Producing Bacteria with Environmental Biotechnology Applications
Agronomy 2021, 11(4), 624; https://doi.org/10.3390/agronomy11040624 - 25 Mar 2021
Abstract
Biosurfactants, a wide group of compounds produced by different microorganisms, generally have less toxicity and are more biodegradable than synthetic surfactants. Biosurfactant-producing bacteria can be found in contaminated environments, such as soils receiving pesticide applications constantly, or in pesticides treatment systems where microorganisms [...] Read more.
Biosurfactants, a wide group of compounds produced by different microorganisms, generally have less toxicity and are more biodegradable than synthetic surfactants. Biosurfactant-producing bacteria can be found in contaminated environments, such as soils receiving pesticide applications constantly, or in pesticides treatment systems where microorganisms are adapted to biodegrading pesticides. Five pesticide-tolerant bacteria previously isolated from a pesticide biopurification system were evaluated as biosurfactant-producers. Pseudomonas rhodesiae C4, Rhodococcus jialingiae C8 and Pseudomonas marginalis C9 strains were positive in qualitative tests. Biosurfactant production by these strains using Bushnell-Haas medium with olive oil at 2% (w/v) was evaluated as emulsification index, oil displacement, droplet collapse test and surface tension. After 144 h, these strains showed a similar emulsification index of >55%. The two Pseudomonas (C4 and C9) strains showed lower superficial tension compared with Rhodococcus strain (C8)—34.47, 37.44 and 47.55 mN/m for strains C4, C9 and C8, respectively. The chemical characterization of the biosurfactants revealed the presence of glycolipids in P. rhodesiae (C4) and glycopeptides in P. marginalis (C9). The degradation of chlorpyrifos increased from 39.2% to 51.6% when biosurfactants produced by P.rhodesiae (C4) were added (10%) with respect to the control. Therefore, biopurification systems are a relevant source of biosurfactant-producing bacteria with environmental biotechnology applications. Full article
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Article
Sentinel-2 Images and Machine Learning as Tool for Monitoring of the Common Agricultural Policy: Calasparra Rice as a Case Study
Agronomy 2021, 11(4), 621; https://doi.org/10.3390/agronomy11040621 - 25 Mar 2021
Abstract
The European Commission introduces the Control by Monitoring through new technologies to manage Common Agricultural Policy funds through the Regulation 2018/746. The advances in remote sensing have been considered one of these new technologies, mainly since the European Space Agency designed the Copernicus [...] Read more.
The European Commission introduces the Control by Monitoring through new technologies to manage Common Agricultural Policy funds through the Regulation 2018/746. The advances in remote sensing have been considered one of these new technologies, mainly since the European Space Agency designed the Copernicus Programme. The Sentinel-1 (radar range) and Sentinel-2 (optical range) satellites have been designed for monitoring agricultural problems based on the characteristics they provide. The data provided by the Sentinel 2 missions, together with the emergence of different scientific disciplines in artificial intelligence —especially machine learning— offer the perfect basis for identifying and classifying any crop and its phenological state. Our research is based on developing and evaluating a pixel-based supervised classification scheme to produce accurate rice crop mapping in a smallholder agricultural zone in Calasparra, Murcia, Spain. Several models are considered to obtain the most suitable model for each element of the time series used; pixel-based classification is performed and finished with a statistical treatment. The highly accurate results obtained, especially across the most significant vegetative development dates, indicate the benefits of using Sentinel-2 data combined with Machine Learning techniques to identify rice crops. It should be noted that it was possible to locate rice crop areas with an overall accuracy of 94% and standard deviation of 1%, which could be increased to 96% (±1%) if we focus on the months of the crop’s highest development state. Thanks to the proposed methodology, the on-site inspections carried out, 5% of the files, have been replaced by remote sensing evaluations of 100% of the analyzed season files. Besides, by adjusting the model input data, it is possible to detect unproductive or abandoned plots. Full article
(This article belongs to the Special Issue Geoinformatics Application in Agriculture)
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Article
Higher Biochar Rate Can Be Efficient in Reducing Nitrogen Mineralization and Nitrification in the Excessive Compost-Fertilized Soils
Agronomy 2021, 11(4), 617; https://doi.org/10.3390/agronomy11040617 - 24 Mar 2021
Abstract
The effects of a high biochar rate on soil carbon mineralization, when co-applied with excessive compost, have been reported in previous studies, but there is a dearth of studies focusing on soil nitrogen. In order to ascertain the positive or snegative effects of [...] Read more.
The effects of a high biochar rate on soil carbon mineralization, when co-applied with excessive compost, have been reported in previous studies, but there is a dearth of studies focusing on soil nitrogen. In order to ascertain the positive or snegative effects of a higher biochar rate on excessive compost, compost (5 wt. %) and three slow pyrolysis (>700 °C) biochars (formosan ash (Fraxinus formosana Hayata), ash biochar; makino bamboo (Phyllostachys makino Hayata), bamboo biochar; and lead tree (Leucaena leucocephala (Lam.) de. Wit), lead tree biochar) were applied (0, 2 and 5 wt. %) to three soils (one Oxisols and two Inceptisols). Destructive sampling occurred at 1, 3, 7, 28, 56, 84, 140, 196, 294, and 400 days to monitor for changes in soil chemistry. The overall results showed that, compared to the other rates, the 5% biochar application rate significantly reduced the concentrations of inorganic N (NO3-N + NH4+-N) in the following, decreasing order: lead tree biochar > bamboo biochar > ash biochar. The soil response in terms of ammonium and nitrate followed a similar declining trend in the three soils throughout the incubation periods, with this effect increasing in tandem with the biochar application rate. Over time, the soil NO3-N increased, probably due to the excessive compost N mineralization; however, the levels of soil NO3-N in the sample undergoing the 5% biochar application rate remained the lowest, to a significant degree. The soils’ original properties determined the degree of ammonium and nitrate reduction after biochar addition. To reduce soil NO3-N pollution and increase the efficiency of compost fertilizer use, a high rate of biochar application (especially with that pyrolyzed at high temperatures (>700 °C)) to excessively compost-fertilized soils is highly recommended. Full article
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Article
Farmers’ Climate Change Adaptation Strategies for Reducing the Risk of Rice Production: Evidence from Rajshahi District in Bangladesh
Agronomy 2021, 11(3), 600; https://doi.org/10.3390/agronomy11030600 - 22 Mar 2021
Cited by 1
Abstract
A lack of adaptive capacities for climate change prevents poor farmers from diversifying agricultural production in Bangladesh’s drought-resilient areas. Climate change adaptation strategies can reduce the production risk relating to unforeseen climatic shocks and increase farmers’ food, income, and livelihood security. This paper [...] Read more.
A lack of adaptive capacities for climate change prevents poor farmers from diversifying agricultural production in Bangladesh’s drought-resilient areas. Climate change adaptation strategies can reduce the production risk relating to unforeseen climatic shocks and increase farmers’ food, income, and livelihood security. This paper investigates rice farmers’ adaptive capacities to adapt climate change strategies to reduce the rice production risk. The study collected 400 farm-level micro-data of rice farmers with the direct cooperation of Rajshahi District. The survey was conducted during periods between June and July of 2020. Rice farmers’ adaptive capacities were estimated quantitatively by categorizing the farmers as high, moderate, and low level adapters to climate change adaptation strategies. In this study, a Cobb–Douglas production function was used to measure the effects of farmers’ adaptive capacities on rice production. The obtained results show that farmers are moderately adaptive in terms of adaptation strategies on climate change and the degree of adaptation capacities. Agronomic practices such as the quantity of fertilizer used, the amount of labor, the farm’s size, and extension contacts have a substantial impact on rice production. This study recommends that a farmer more significantly adjusts to adaptation strategies on climate change to reduce rice production. These strategies will help farmers to reduce the risk and produce higher quality rice. Consequently, rice farmers should facilitate better extension services and change the present agronomic practice to attain a higher adaptation status. It can be very clearly seen that low adaptability results in lower rice yields. Full article
(This article belongs to the Special Issue Smallholder Agriculture: Where We Are and Pathways towards the Future)
Article
Chemical Properties and Bacterial Community Reaction to Acidified Cattle Slurry Fertilization in Soil from Maize Cultivation
Agronomy 2021, 11(3), 601; https://doi.org/10.3390/agronomy11030601 - 22 Mar 2021
Abstract
Acidified slurry is a novel organic fertilizer that limits gaseous ammonia emissions and reduces nitrogen losses. Our research aimed to determine the effects of short-term fertilization with acidified slurry on the chemical properties and bacterial community of soil used for maize cultivation. In [...] Read more.
Acidified slurry is a novel organic fertilizer that limits gaseous ammonia emissions and reduces nitrogen losses. Our research aimed to determine the effects of short-term fertilization with acidified slurry on the chemical properties and bacterial community of soil used for maize cultivation. In the months after spreading, raw slurry fertilization had a significant impact on the increase in values of N-NO3. In contrast, soil fertilized with acidified slurry had lower N-NO3 values when compared to raw slurry fertilization treatments. Bacterial sequencing using Illumina MiSeq showed no differences in the genetic diversity of bacterial communities. In all tested soil samples, dominants at the phylum level were Actinobacteria, Proteobacteria, and Acidobacteria, while dominants at the class level were Actinobacteria, Alphaproteobacteria, Thermoleophilia, Gammaproteobacteria, and Acidimicrobiia. The values of biodiversity indices (Shannon index, Simpson index) in tested samples were similar. Our results suggest that short-term fertilization with acidified slurry does not adversely affect the biodiversity and structure of the bacterial communities and has a slight impact on soil chemical properties. Full article
(This article belongs to the Special Issue Protection of Biodiversity of Agricultural Soils)
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Article
Targeting Hotspots to Achieve Sustainable Nitrogen Management in China’s Smallholder-Dominated Cereal Production
Agronomy 2021, 11(3), 557; https://doi.org/10.3390/agronomy11030557 - 15 Mar 2021
Abstract
Agriculture in China, which is dominated by millions of smallholders, consumes 30% of global nitrogen (N) fertilizers and results in a high surplus and vast spatial variability of N. Identifying the N-management practices of smallholder farmers is critical to pursuing sustainable agricultural productivity. [...] Read more.
Agriculture in China, which is dominated by millions of smallholders, consumes 30% of global nitrogen (N) fertilizers and results in a high surplus and vast spatial variability of N. Identifying the N-management practices of smallholder farmers is critical to pursuing sustainable agricultural productivity. However, at the national scale, N budgets and spatial distribution based on first-hand data from smallholder farmers are not well characterized. Here, using data collected from a national survey involving 7.3 million farmers from 2005 to 2014, we quantified N budgets, evaluated their spatial variation, and revealed “hotspots” of low N removal and high N surplus for wheat, maize, and rice systems at the county level. The N surplus for cereal crops was 122–140 kg N ha−1, which is equivalent to an annual N surplus of 11.3 megaton (Mt). Chemical N was the most important contributor to the N surplus, while farmers used manure N less than 10% of the total N input. N budgets exhibited vast spatial variation at the county level, and the hotspots contributed to 56% of the total N surplus in China. Targeted efforts for eliminating hotspots could increase N removal by 13–21%, increase N use efficiency to 0.55–0.70, and significantly reduce the N surplus for all counties and crops, by 42%. Based on farmer survey data, our results provide updated estimates of N budgets and highlight hotspots of N surplus for cereal crop systems in China. They provide a benchmark for the development of new agricultural N management policies and technologies in the country. Full article
(This article belongs to the Section Farming Sustainability)
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Article
L-3,4-dihydroxyphenylalanine Accumulation in Faba Bean (Vicia faba L.) Tissues during Different Growth Stages
Agronomy 2021, 11(3), 502; https://doi.org/10.3390/agronomy11030502 - 08 Mar 2021
Abstract
L-3,4-dihydroxyphenylalanine (L-dopa)-rich faba (Vicia faba L.) tissues are a potentially useful source for its pharmaceutical purpose, although the species contains health curious vicine and convicine in the seeds. We determined the contents of L-dopa, vicine, and convicine in different tissues of faba [...] Read more.
L-3,4-dihydroxyphenylalanine (L-dopa)-rich faba (Vicia faba L.) tissues are a potentially useful source for its pharmaceutical purpose, although the species contains health curious vicine and convicine in the seeds. We determined the contents of L-dopa, vicine, and convicine in different tissues of faba plants throughout the entire growth period. The three compounds accumulated in germinating sprouts and showed high contents at 8 days of germination, especially in the epicotyl containing 132.33 mg∙g−1 DW of L-dopa, 19.81 mg∙g−1 DW of vicine, and 10.38 mg∙g−1 DW of convicine, respectively. We compared the contents of the three compounds among leaves of different ages in plants at different growth stages. The samples could be ranked, from highest to lowest content, ranging from 11.11 to 81.82 mg∙g−1 DW, as follows: new leaves > young leaves > old leaves; and vegetative > flowering > ripening. Vicine and convicine were not detected in leaves or flowers. The L-dopa content was high in flowers, especially young flower buds, ranging from 36.51 to 100.70 mg∙g−1 DW. In older flowers, the L-dopa content tended to decrease as the calyx and petal parts developed. In addition, the three compounds showed decreasing contents in pods, stems, and roots with increasing plant age. The results of this study provide information on the timing and extent of L-dopa, vicine, and convicine accumulation in different faba tissues, and indicate that various by-products, especially new/young leaves and flowers, are potential sources of natural L-dopa. Full article
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Article
Utilization of Quasi-Zenith Satellite System for Navigation of a Robot Combine Harvester
Agronomy 2021, 11(3), 483; https://doi.org/10.3390/agronomy11030483 - 05 Mar 2021
Abstract
The purpose of this study is to evaluate the performance of a robot combine harvester by comparing the Centimeter Level Augmentation Service (CLAS) and the Multi-Global Navigation Satellite System (GNSS) Advanced Demonstration tool for Orbit and Clock Analysis (MADOCA) from the Quasi-Zenith Satellite [...] Read more.
The purpose of this study is to evaluate the performance of a robot combine harvester by comparing the Centimeter Level Augmentation Service (CLAS) and the Multi-Global Navigation Satellite System (GNSS) Advanced Demonstration tool for Orbit and Clock Analysis (MADOCA) from the Quasi-Zenith Satellite System (QZSS) by using the Real Time Kinematic (RTK) positioning technique as a reference. The first section of this study evaluates the availability and the precision under static conditions by measuring the activation time, the reconnection time, and obtaining a Twice Distance Root Mean Square (2DRMS) of 0.04 m and 0.10 m, a Circular Error Probability (CEP) of 0.03 m and 0.08 m, and a Root Mean Square Error (RMSE) of 0.57 m and 0.54 m for the CLAS and MADOCA, respectively. The second section evaluates the accuracy under dynamic conditions by using a GNSS navigation-based combine harvester running in an experimental field. The results show that the RMSE of the lateral deviation is between 0.04 m and 0.69 m for MADOCA and between 0.03 m and 0.31 m for CLAS; which suggest that the CLAS positioning augmentation system can be utilized for the robot combine harvester if the user considers these accuracy and dynamic characteristics. Full article
(This article belongs to the Special Issue Automation for Digital Farming)
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Article
Agronomic Traits in Oilseed Rape (Brassica napus) Can Predict Foraging Resources for Insect Pollinators
Agronomy 2021, 11(3), 440; https://doi.org/10.3390/agronomy11030440 - 27 Feb 2021
Abstract
Mass-flowering crops, such as oilseed rape (OSR; Brassica napus), provide pulses of nectar and pollen, helping to support pollinators and their pollination services in agricultural landscapes. Despite their value to declining pollinators, varietal in-field OSR testing focusses on agronomic traits, with floral [...] Read more.
Mass-flowering crops, such as oilseed rape (OSR; Brassica napus), provide pulses of nectar and pollen, helping to support pollinators and their pollination services in agricultural landscapes. Despite their value to declining pollinators, varietal in-field OSR testing focusses on agronomic traits, with floral resources being largely overlooked. OSR has a high varietal turnover, and consequently, floral resource data collected for a specific variety quickly become redundant. Here, we explore the potential to predict floral resource availability using agronomic trait data routinely collected in varietal trials. To build predictive models, we investigated the relationships between agronomic traits and pollen and nectar availability in 19 OSR varieties. Nectar quality was positively influenced by early vigour, as well as winter hardiness in conventional varieties and stem stiffness in hybrid varieties. Pollen quantity was driven by different traits, with early maturation having a negative impact in conventional varieties and resistance to lodging having a positive impact in hybrid varieties. Our study highlights the potential to predict floral resources using agronomic trait data, enabling the rapid assessment of these key resources in future OSR varieties without costly sampling. Agronomic traits relating to increased nectar quality were also agronomically favourable, indicating benefits to both pollinators and growers. The inclusion of modelled floral resource data in recommended varietal lists would enable growers to make informed decisions about varietal selection based on local pollinator populations. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Planting Density Interferes with Strawberry Production Efficiency in Southern Brazil
Agronomy 2021, 11(3), 408; https://doi.org/10.3390/agronomy11030408 - 24 Feb 2021
Abstract
In the search for more efficient production systems, many changes have occurred in the strawberry production sector. Planting density is one of the management techniques that most interferes with the quality of fruits and production aspects. This study aimed to evaluate the effect [...] Read more.
In the search for more efficient production systems, many changes have occurred in the strawberry production sector. Planting density is one of the management techniques that most interferes with the quality of fruits and production aspects. This study aimed to evaluate the effect of different planting densities on the photosynthetic characteristics, fruit quality, and production of the strawberry cultivar Pircinque. The study was conducted in the 2018/2019 and 2019/2020 harvests in Lages, Santa Catarina, Brazil. The treatments consisted of plant spacing of 5, 10, 15, 20, 25, and 30 cm. The experimental design was in randomized blocks, with four blocks and plots of 20 plants. Plant spacing interfered with fruit quality, photosynthetic efficiency, production, productivity, and economic return. Due to the fruits of Pircinque having a higher quality than other cultivars, the planting spacing between 5 and 15 cm allows meeting the fruit’s main production and quality requirements. However, it is up to the producer to adapt the management if opting for higher planting densities, which allow for a greater economic viability of the business. Full article
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Article
Impact of Integrated Agronomic Practices on Soil Fertility and Respiration on the Indo-Gangetic Plain of North India
Agronomy 2021, 11(2), 402; https://doi.org/10.3390/agronomy11020402 - 23 Feb 2021
Abstract
Global agricultural production is accountable for the emission of ~30% of greenhouse gases. Therefore, the wide-scale adoptions of low-input, soil-friendly, and resource-conserving agronomic practices are imperative for the ‘planet healthy food production’ and also for reducing the carbon emissions from agricultural soil. In [...] Read more.
Global agricultural production is accountable for the emission of ~30% of greenhouse gases. Therefore, the wide-scale adoptions of low-input, soil-friendly, and resource-conserving agronomic practices are imperative for the ‘planet healthy food production’ and also for reducing the carbon emissions from agricultural soil. In this context, the present study aimed to analyze the impacts of integrated agronomic interventions i.e., the application of arbuscular mycorrhizal fungi (AMF) + reduced tillage (RT), biochar + RT, and AMF + biochar + RT, on spatiotemporal variations in soil-quality and soil-sustainability indicators, including microbial and soil respiration, in the Indo-Gangetic Plain (IGP) of North India. For this, field experiments on the above-mentioned agronomic interventions were employed using three different staple crops (Zea mays, Vigna mungo, and Brassica juncea) growing in three different agro-climatic zones of IGP (Varanasi, Sultanpur, and Gorakhpur) in a randomized block design. Periodic data collection was done to analyze the changes in physiochemical, biological, and biochemical properties of the soil, and statistical analyses were done accordingly. Irrespective of the sites, the experimental results proved that the integrated application of AMF + biochar + RT in V. mungo resulted in the highest soil organic carbon (i.e., 135% increment over the control) and microbial biomass carbon (24%), whereas the same application (i.e., AMF + biochar + RT) in Z. mays had the maximum reduction in microbial (32%) and soil (44%) respiration. On the other hand, enhanced occurrence of glomalin activity (98%) was noted in Z. mays cropping for all the sites. Significant negative correlation between soil respiration and glomalin activity under AMF + biochar + RT (−0.85), AMF + RT (−0.82), and biochar + RT (−0.62) was an indication of glomalin’s role in the reduced rate of soil respiration. The research results proved that the combined application of AMF + biochar + RT was the best practice for enhancing soil quality while reducing respiration. Therefore, the development of suitable packages of integrated agronomic practices is essential for agricultural sustainability. Full article
(This article belongs to the Section Farming Sustainability)
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Article
Ghanaian Cocoa (Theobroma cacao L.) Bean Shells Coproducts: Effect of Particle Size on Chemical Composition, Bioactive Compound Content and Antioxidant Activity
Agronomy 2021, 11(2), 401; https://doi.org/10.3390/agronomy11020401 - 23 Feb 2021
Cited by 1
Abstract
The worldwide cocoa bean shell (CBS) generation is estimated at around 900,000 tons. In their composition, this coproduct showed several bioactive compounds like methylxanthines or polyphenolic compounds. Thus, the aim of this work was to investigate the effects of different particle sizes on [...] Read more.
The worldwide cocoa bean shell (CBS) generation is estimated at around 900,000 tons. In their composition, this coproduct showed several bioactive compounds like methylxanthines or polyphenolic compounds. Thus, the aim of this work was to investigate the effects of different particle sizes on the chemical composition, physico-chemical, bioactive compounds content, and antioxidant properties of flours obtained from cocoa (Theobroma cacao L.) bean shells. The flours obtained from CBS with different particle sizes had high content of dietary fiber (61.18–65.58 g/100 g). The polyphenolic profile identified seven compounds being epicatechin and catechin (values ranged 4.56–6.33 and 2.11–4.56 mg/g, respectively) as the most abundant compounds. Additionally, the methylxanthines theobromine and caffeine were quantified with values ranging from 7.12 to 12.77 and 4.02 to 6.13 mg/g, respectively. For the fatty acid profile, the principal compounds identified were oleic, stearic and palmitic acids. CBS had antioxidant capacity with all methods assayed. For DPPH, ABTS and FRAP assays values ranged between 2.35–5.53, 3.39–11.55, and 3.84–7.62 mg Trolox equivalents/g sample, respectively. This study suggests that cocoa bean shells may constitute a valuable coproduct for the food industry due to its high content in valuable bioactive compounds. Full article
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Article
Species Interactions and Nitrogen Use during Early Intercropping of Intermediate Wheatgrass with a White Clover Service Crop
Agronomy 2021, 11(2), 388; https://doi.org/10.3390/agronomy11020388 - 22 Feb 2021
Abstract
Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the 15N isotope dilution method demonstrated interspecific competition and use of N from the soil and N2 fixation in intermediate wheatgrass (Thinopyrum [...] Read more.
Perennial grain crops intercropped with legumes are expected to use nitrogen (N) resources efficiently. A pot experiment using the 15N isotope dilution method demonstrated interspecific competition and use of N from the soil and N2 fixation in intermediate wheatgrass (Thinopyrum intermedium (Host) Barkworth & D.R. Dewey, IWG) and white clover (Trifolium repens L., WC) intercrops at five species-relative frequencies and four levels of inorganic N fertilizer in a replacement series design. The proportion of N in WC derived from the atmosphere increased from 39.7% in a sole crop to 70.9% when intercropped with IWG, and 10.1% N in IWG transferred from WC. Intermediate wheatgrass showed high fitness with maintained high total dry matter production at low relative frequencies. Decreasing IWG-relative frequency only increased dry matter and N accumulation of WC, resulting in increased amounts of N2 fixed. Increased levels of N fertilization increased the proportion of N acquired from the fertilizer in IWG and WC but decreased the N fixed by WC and N absorbed by IWG from the soil. Our study indicates that WC supply sufficient fixed N2 for IWG intercrop biomass yields under appropriate levels of soil N fertility and species-relative frequencies. Full article
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Article
Investigating Combined Drought- and Heat Stress Effects in Wheat under Controlled Conditions by Dynamic Image-Based Phenotyping
Agronomy 2021, 11(2), 364; https://doi.org/10.3390/agronomy11020364 - 18 Feb 2021
Abstract
As drought and heat stress are major challenges for crop productivity under future climate changes, tolerant cultivars are highly in demand. This study investigated the potential of existing Nordic wheat genotypes to resist unfavorable conditions. Four genotypes were selected based on their heat [...] Read more.
As drought and heat stress are major challenges for crop productivity under future climate changes, tolerant cultivars are highly in demand. This study investigated the potential of existing Nordic wheat genotypes to resist unfavorable conditions. Four genotypes were selected based on their heat sensitivity (heat-sensitive: LM19, SF1; heat-tolerant: LM62, NS3). At the tillering stage, the plants were subjected to four treatments under controlled conditions: control, drought, heat and combined drought and heat stress. The morpho-physiological performance was quantified during the early and late phase of stress, as well as the recovery phase. We applied an integrative image-based phenotyping approach monitoring plant growth dynamics by structural Red Green Blue (RGB) imaging, photosynthetic performance by chlorophyll fluorescence imaging and transpiration efficiency by thermal infrared imaging. The results demonstrated that the selected genotypes were moderately affected in their photosynthetic efficiency and growth under drought stress, whereas heat and combined stress caused rapid reductions in photosynthesis and growth. Furthermore, drought stress had a major impact on canopy temperature. The NS3 genotype was the most robust genotype, as indicated by its improved response under all stress treatments due to its relatively small biomass. However, the genotypes showed different tolerance to individual and combined stress. Full article
(This article belongs to the Special Issue Phenotyping for Resilient and Sustainable Crops)
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Article
Use of Biochar-Compost for Phosphorus Availability to Maize in a Concretionary Ferric Lixisol in Northern GHANA
Agronomy 2021, 11(2), 359; https://doi.org/10.3390/agronomy11020359 - 17 Feb 2021
Abstract
A pot experiment was conducted to investigate the effect of biochar-compost on availability of P for maize cultivation in a concretionary Lixisol of northern Ghana and residual soil characteristics thereof. Sawdust biochar was co-composted with kitchen waste and cow dung in various proportions. [...] Read more.
A pot experiment was conducted to investigate the effect of biochar-compost on availability of P for maize cultivation in a concretionary Lixisol of northern Ghana and residual soil characteristics thereof. Sawdust biochar was co-composted with kitchen waste and cow dung in various proportions. Four biochar-composts were selected based on their superior carbon and available P content, lower pH, and electrical conductivity (EC). These were amended to attain the standard phosphorus requirement (SPR) and half the SPR of the Lixisol. Triple superphosphate and (NH4)2 SO4 were, respectively, applied as inorganic fertilizer to meet the SPR and the average total nitrogen of the selected biochar-compost treatments. A control without any soil amendment was included. Maize was grown to tasseling (eight weeks) and shoot dry matter and P uptake determined. A 2.71 to 3.71-fold increase in P uptake led to a 1.51 to 2.33-fold increase in shoot dry matter in biochar-compost-amended soils over the control. Residual soil C, pH, and total and available P in the biochar-compost-amended soils were enhanced. Biochar-composts at half the SPR level produced maize with higher shoot dry matter than the equivalent inorganic amendment at full SPR. Full article
Article
Agronomic Comparisons of Heirloom and Modern Processing Tomato Genotypes Cultivated in Organic and Conventional Farming Systems
Agronomy 2021, 11(2), 349; https://doi.org/10.3390/agronomy11020349 - 15 Feb 2021
Abstract
The yield and fruit quality of processing tomatoes (Solanum lycopersicum L.) have increased markedly over the past decades. The aim of this work was to assess the effects of the organic (OFS) and conventional farming systems (CFS) on the main agronomic parameters [...] Read more.
The yield and fruit quality of processing tomatoes (Solanum lycopersicum L.) have increased markedly over the past decades. The aim of this work was to assess the effects of the organic (OFS) and conventional farming systems (CFS) on the main agronomic parameters involved in processing tomato yield components and fruit quality traits of heirloom and modern genotypes. Marketable yield increased from heirloom to modern genotypes, both in OFS and in CFS, showing a difference of ≈20 t per hectare in favor of CFS. Total fruit yield (TY) was not improved from heirloom to modern assessed genotypes, and a difference of ≈35 t per hectare was observed in favor of CFS. In both farming systems, the highest marketable yield of modern genotypes was due to a higher number of fruits per plant, harvest index, nitrogen agronomic efficiency (NAE), and fruit water productivity. Moreover, the main growth parameters involved in the yield differences between OFS and CFS were the number of leaves per plant, the average fruit weight, the normalized difference vegetation index (NDVI), and NAE. It is noteworthy that fruit quality improvement in terms of color and brix per hectare was paralleled by a decrease of tomato pH in both farming systems. According to our results, we conclude that to reduce the current yield gap between OFS and CFS, agronomic and breeding efforts should be undertaken to increase leaf area index, fruit number per plant, and NAE for better genotype adaptation to organic farming systems. Full article
(This article belongs to the Special Issue Organic vs. Conventional Cropping Systems)
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Article
Pollen Paternity Can Affect Kernel Size and Nutritional Composition of Self-Incompatible and New Self-Compatible Almond Cultivars
Agronomy 2021, 11(2), 326; https://doi.org/10.3390/agronomy11020326 - 12 Feb 2021
Cited by 1
Abstract
Breeding programs for horticultural tree crops focus on enhancing productivity, including developing tolerance to pests and diseases and improving crop quality. Pollination services are often critical for crop production, and pollen parents can affect crop quality. We often do not know which pollen [...] Read more.
Breeding programs for horticultural tree crops focus on enhancing productivity, including developing tolerance to pests and diseases and improving crop quality. Pollination services are often critical for crop production, and pollen parents can affect crop quality. We often do not know which pollen parents produce highest quality offspring or, in self-compatible cultivars, how much of the crop comes from cross- versus self-pollination. We quantified the proportions of self- and cross-paternity in an open pollination setting of five standard commercial almond cultivars and of six new almond cultivars selected for yield, kernel size, taste or self-compatibility. We assessed how pollination by different parents affected kernel size and nutritional quality. Kernels from most commercial cultivars and from the new cultivars selected for taste and size resulted almost entirely from cross-pollination. Most kernels from the commercial cultivar ‘Price’ resulted from cross-pollination but 21% resulted from self-pollination. In contrast, 48–91% of kernels from the new self-compatible cultivars resulted from self-pollination. Different cross-pollen parents did not greatly affect kernel size or quality. The proportions of self-paternity in the new self-compatible cultivars varied strongly in an open pollination setting suggesting that some cultivars may be good candidates for establishing monovarietal orchards. Full article
(This article belongs to the Special Issue Pollinator Diversity and Pollination in Agricultural Systems)
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Article
Cultivar Determines Fatty Acids and Phenolics Dynamics for Olive Fruit and Oil in Super-High-Density Orchards
Agronomy 2021, 11(2), 313; https://doi.org/10.3390/agronomy11020313 - 10 Feb 2021
Abstract
The dynamics of maturation index, water and oil concentrations, and total phenols in olive fruit, together with fatty acids and total phenols content in olive oil, was studied as a function of time after flowering for super-high-density ‘Arbequina’, ‘Arbosana’ and ‘Koroneiki’ using data [...] Read more.
The dynamics of maturation index, water and oil concentrations, and total phenols in olive fruit, together with fatty acids and total phenols content in olive oil, was studied as a function of time after flowering for super-high-density ‘Arbequina’, ‘Arbosana’ and ‘Koroneiki’ using data collected in three seasons. Oil concentration increased linearly from the middle of August until reaching a plateau by the end of November for all three cultivars, with ‘Koroneiki’ (45.7 g/100 g) and ‘Arbosana’ (45.4 g/100 g) showing higher maximum oil concentration than ‘Arbequina’ (41.8 g/100 g). While total phenols in the fruit decreased linearly during the harvest for all three cultivars, phenolics in oil peaked at 180 days after flowering (400 mg/kg) for ‘Arbequina’ and at 160 days after flowering (600 mg/kg) for ‘Koroneiki’. For ‘Arbosana’, total phenols in oil decreased linearly with a maximum of 400 mg/kg for early harvest oils. Fatty acid dynamics was largely affected by genotype, with ‘Arbequina’ displaying the largest variation in fatty acid concentrations along the season. ‘Koroneiki’ presented the highest values of oleic acid (73.0–77.1%), followed by ‘Arbosana’ (70.2–72.4%) and ‘Arbequina’ (64.4–74.0%). Results presented here are useful for growers to make planting and harvesting decisions, for producers to understand the differences in oil made from the most common super-high-density cultivars during the harvest seasons, and for regulators to consider legal standards for authentic olive oil. Full article
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Article
Tracking Changes on Soil Structure and Organic Carbon Sequestration after 30 Years of Different Tillage and Management Practices
Agronomy 2021, 11(2), 291; https://doi.org/10.3390/agronomy11020291 - 05 Feb 2021
Cited by 2
Abstract
Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), [...] Read more.
Long-term field trials are essential for monitoring the effects of sustainable land management strategies for adaptation and mitigation to climate change. The influence of more than thirty years of different management is analyzed on extensive crops under three tillage systems, conventional tillage (CT), minimum tillage (MT), and no-tillage (NT), and with two crop rotations, monoculture winter-wheat (Triticum aestivum L.) and wheat-vetch (Triticum aestivum L.-Vicia sativa L.), widely present in the center of Spain. The soil under NT experienced the largest change in organic carbon (SOC) sequestration, macroaggregate stability, and bulk density. In the MT and NT treatments, SOC content was still increasing after 32 years, being 26.5 and 32.2 Mg ha−1, respectively, compared to 20.8 Mg ha−1 in CT. The SOC stratification (ratio of SOC at the topsoil/SOC at the layer underneath), an indicator of soil conservation, increased with decreasing tillage intensity (2.32, 1.36, and 1.01 for NT, MT, and CT respectively). Tillage intensity affected the majority of soil parameters, except the water stable aggregates, infiltration, and porosity. The NT treatment increased available water, but only in monocropping. More water was retained at the permanent wilting point in NT treatments, which can be a disadvantage in dry periods of these edaphoclimatic conditions. Full article
(This article belongs to the Special Issue Soil Healthy in Agro-ecosystems)
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Article
Optimization of Tomato Productivity Using Flowering Time Variants
Agronomy 2021, 11(2), 285; https://doi.org/10.3390/agronomy11020285 - 04 Feb 2021
Abstract
The control of flowering time is a major contributing factor to the improvement of crop yield by optimizing plant growth in a crop cycle. Genetic variants that determine flowering time can provide insights into optimizing flowering time for higher yields and other beneficial [...] Read more.
The control of flowering time is a major contributing factor to the improvement of crop yield by optimizing plant growth in a crop cycle. Genetic variants that determine flowering time can provide insights into optimizing flowering time for higher yields and other beneficial traits in tomato crops. Here, we examined a collection of flowering time variants to assess their effects on biomass and total tomato yields. Five late flowering (lf), thirteen large plant (lp), and seven floral homeotic (fh) mutants were identified as flowering time variants that could be rearranged according to leaf production in the primary shoot meristem (PSM). A flowering time continuum of mutants was translated into a positive continuum of biomass yield with more leaves, branches, and floral organs. The flowering time continuum showed an optimal curve of fruit yield, indicating a certain late flowering time as optimal for fruit yield, with the yield gradually decreasing in both directions with earlier or later flowering times. We isolated lf1, lf10, lp22, and fh13 as high-yielding genotypes with optimal flowering time, showing a new balance between the vegetative and flowering phases of tomato. Additionally, lp8, fh8, and fh15 produced extremely high biomass in leaves, axillary shoots, and floral organs due to late flowering in shoot apices with additional production of floral organs and lateral shoot. Our new late-flowering variants provide new genetic resources that can be used to optimize crop yield by fine-tuning flowering time, and future molecular studies could be conducted by revisiting our yield model. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Development and Characterization of Wheat-Agropyron cristatum Introgression Lines Induced by Gametocidal Genes and Wheat ph1b Mutant
Agronomy 2021, 11(2), 277; https://doi.org/10.3390/agronomy11020277 - 02 Feb 2021
Abstract
The P genome of Agropyron cristatum Gaertn. contains many desirable genes that can be utilized as genetic resources to improve wheat. In this research, we used both the gametocidal chromosome 2Cc and the pairing homologous gene (Ph1b) mutant to induce [...] Read more.
The P genome of Agropyron cristatum Gaertn. contains many desirable genes that can be utilized as genetic resources to improve wheat. In this research, we used both the gametocidal chromosome 2Cc and the pairing homologous gene (Ph1b) mutant to induce structural aberrations and translocations between wheat and the 4P, 5P, and 6P genome chromosomes. By using the two approaches, a total of 19 wheat-A. cristatum translocations have been identified, in which 13 were induced by the Triticum aestivum cv. Chinese Spring (CS) ph1b mutant (CS ph1b) and six were induced by gametocidal chromosome 2Cc from Aegilops cylindrica Host. The wheat-4P, -5P and -6P A. cristatum translocations were characterized by in situ hybridization and by a set of conserved orthologous set (COS) molecular markers. The aberrations included centromeric translocations, terminal translocations, dicentric translocations, and deletions. The average induction frequency of chromosome structural aberrations was 10.9% using gametocidal 2Cc chromosome and 8.8% using ph1b mutant. The highest frequency obtained was for chromosome 4P using both approaches. All the wheat-A. cristatum translocation lines obtained were valuable for identifying A. cristatum chromosome 4P, 5P, and 6P related genes. In addition, these lines provided genetic resources and new germplasm accessions for the genetic improvement of wheat. Full article
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Article
Herbicide-Based Weed Management for Soybean Production in the Far Eastern Region of Russia
Agronomy 2020, 10(11), 1823; https://doi.org/10.3390/agronomy10111823 - 20 Nov 2020
Cited by 2
Abstract
This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, [...] Read more.
This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in much lower soybean yield than the weed-free plot. The sequential application of acetochlor (PRE), followed by either bentazon + acifluorfen (POST) at 30 DAS in 2012 or bentazon + imazamox (POST) at 60 DAS in 2013 showed the best performance in soybean yields, 1.7 t and 1.9 t ha−1, respectively, provided with 724.5 US$ and 1155.6 US$ ha−1 of economic returns. For alternative PRE herbicides of acetochlor, which is now banned, our tests of the sequential application of S-metolachlor with other POST herbicides and the sole application of other PRE herbicides revealed that S-metolachlor and clomazone could also be considered. Our results thus demonstrate that the sequential applications of PRE and POST herbicides should be incorporated into the weed management system for soybean production in Primorsky krai, Russia. Full article
(This article belongs to the Section Weed Science and Weed Management)
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Article
Biomass Performance and Competition Effects in an Established Temperate Agroforestry System of Willow and Grassland—Results of the 2nd Rotation
Agronomy 2020, 10(11), 1819; https://doi.org/10.3390/agronomy10111819 - 19 Nov 2020
Cited by 1
Abstract
Agroforestry systems (AFSs) are promoted as environmentally friendly and climate-change-resilient cultivation systems with the potential of increasing ecosystem services. Especially under temperate climatic conditions, the implementation in agricultural practice is low so far, inter alia due to the lack of knowledge regarding longer-term [...] Read more.
Agroforestry systems (AFSs) are promoted as environmentally friendly and climate-change-resilient cultivation systems with the potential of increasing ecosystem services. Especially under temperate climatic conditions, the implementation in agricultural practice is low so far, inter alia due to the lack of knowledge regarding longer-term effects of such systems. This study investigated biomass yields and crop development during the second rotation of an alley cropping system with willows (clone “Tordis” ((Salix schwerinii x S. viminalis) x S. vim.)) and grassland that was established in March 2011, as reported in a former study of the authors. Two grassland swards (white clover grass (Lolium perenne L. and Trifolium repens L.) (CG) and a diversity mixture with 32 plant species (DIV)) were proven in an intensive (3/4 cuts per year) and extensive management system (two cuts per year). Total yield (sum of three years) of AFS increased substantially in the second rotation (year four to six after establishment of the AFS). This was particularly due to a fivefold increase in woody biomass. At the same time, yields of grassland biomass decreased slightly. Biomass of CG outperformed DIV, especially in the intensive managed systems with a dry matter (DM) yield of 18 t ha−1, compared to 12.6 t ha−1. However, AFS grassland yields were always lower than yields of reference areas with grassland in pure stand. Nevertheless, lower yields are probably caused by competition effects between woody crops and grassland. Grassland yields along transects across the grassland alleyways showed a strong decrease in the border areas in all treatments. Higher grassland yields in the alley center did not compensate yield reductions in border areas. Furthermore, the botanical composition of grassland was modified in border areas with reduced legume DM contribution and increases of both grasses and forbs. Thus, the width of grassland alleys with 9 m caused strong competition effects by the willows. Full article
(This article belongs to the Special Issue Alley Cropping—Agroforestry Systems)
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Article
Antifungal Effects of Rhizospheric Bacillus Species Against Bayberry Twig Blight Pathogen Pestalotiopsis versicolor
Agronomy 2020, 10(11), 1811; https://doi.org/10.3390/agronomy10111811 - 18 Nov 2020
Cited by 4
Abstract
Bayberry is an attractive, nutritious, and popular fruit in China. The plant fungal pathogen Pestalotiopsis versicolor XJ27 is the causative agent of bayberry twig blight disease, which severely affects bayberry production. Traditional control techniques, such as chemical fungicides, are being used to control [...] Read more.
Bayberry is an attractive, nutritious, and popular fruit in China. The plant fungal pathogen Pestalotiopsis versicolor XJ27 is the causative agent of bayberry twig blight disease, which severely affects bayberry production. Traditional control techniques, such as chemical fungicides, are being used to control this disease; however, these techniques cause environmental and health hazards. In this study, we screened sweet potato rhizospheric bacteria with biocontrol potentials against P. versicolor XJ27, the bayberry twig blight pathogen. Ten isolates showed inhibition; Bacillus siamensis S3 and Bacillus tequilensis S5 showed the highest fungal growth inhibition. The antagonistic bacterial culture suspensions of S3 and S5 inhibited the mycelial growth by 82.9% and 76.2%, respectively. Their extracellular culture filtrates had mycelial growth inhibition of 86.8% and 82.2%, respectively. In detached leaf assay, the extracellular culture filtrates of S3 and S5 inhibited the size of the leaf lesion by 82.3% and 76.2%, respectively. SEM and TEM imaging showed a severe hyphal-damaged structure caused by the antagonistic bacteria. The fungal inhibition mechanisms might employ the hydrolytic enzymes and lipopeptides produced by the bacteria. Both the S3 and S5 have chitinase and protease activity; they produce a series of lipopeptides such as surfactin, iturin, and mycosubtilin. Therefore, we can suggest these bacteria as biocontrol agents for bayberry twig blight disease as an alternative to fungicides based upon their attributes of antifungal activity. Full article
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Article
The Effect of Organic and Conventional Farming Systems with Different Tillage on Soil Properties and Enzymatic Activity
Agronomy 2020, 10(11), 1809; https://doi.org/10.3390/agronomy10111809 - 17 Nov 2020
Cited by 1
Abstract
The chemical properties and enzymatic activity of the surface soil horizon were compared between an organic farm (OF) (crop rotation with legume plants, fertilisation with manure) and a conventional farm (CF) (simplified crop rotation, mineral fertilisation, chemical crop protection products). In the years [...] Read more.
The chemical properties and enzymatic activity of the surface soil horizon were compared between an organic farm (OF) (crop rotation with legume plants, fertilisation with manure) and a conventional farm (CF) (simplified crop rotation, mineral fertilisation, chemical crop protection products). In the years 2001-2017 on the OF (near the village of Juchowo, northern Poland), a reduced tillage system (ploughless) was used, while plough cultivation was used on a CF located in its immediate vicinity. The parameters used to assess the properties of soils were: particle size composition, pH, total organic carbon (TOC) and total nitrogen (TN), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON). The activity of dehydrogenases (DEH), catalase (CAT), alkaline phosphatase (AlP) and acid phosphatase (AcP) and the content of easily extractable glomalin-related soil protein (EEGRSP) were also determined. Sixteen years of soil use in accordance with ecological principles significantly increased the average content of TOC, NT, DOC and DON. Soil samples rich in TOC and DOC showed significantly higher DEH and AcP activity, and EEGRSP content. Statistical analysis showed that the activity of DEH, AlP and CAT in the soil was significantly higher for the OF than for the conventional cultivation system. Limiting soil cultivation procedures on the OF improved the balance of soil organic matter (SOM) and pH value, and significantly increased the content of EEGRSP as compared to the cultivation system used on the CF. Full article
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Article
Aerial Application Methods for Control of Weed Species in Fallow Farmlands in Texas
Agronomy 2020, 10(11), 1764; https://doi.org/10.3390/agronomy10111764 - 12 Nov 2020
Cited by 1
Abstract
Prolific growth of weeds, especially when followed by abundant rainfall, is common in Texas farmlands during early winter and progresses into spring when farmers begin chiseling and disking operations for spring-seeded cropping. This research sought to develop aerial application technologies designed to control [...] Read more.
Prolific growth of weeds, especially when followed by abundant rainfall, is common in Texas farmlands during early winter and progresses into spring when farmers begin chiseling and disking operations for spring-seeded cropping. This research sought to develop aerial application technologies designed to control unwanted vegetation in croplands left fallow until spring. The aerial nozzles used in the study were conventional hydraulic (CP), rotary atomizer, and electrostatically (ES) charged nozzles. Glyphosate at 0.4145 kg ae·ha−1 was applied on weeds using a fixed-wing aircraft equipped with various aerial nozzles used as treatments. The spray application rate for the conventional and rotary atomizer nozzles was 28.1 L·ha−1, while that for the ES charged nozzle was 9.4 L·ha−1. Aerial and ground-based remote sensing and visual estimates quantified weed vigor and canopy health. Both the CP and rotary atomizer nozzles were efficacious in suppressing weeds. ES charged on nozzles at one-third of the spray application rate of the CP and the rotary atomizer nozzles were equally effective in reducing weed vigor. More aerially applied replicated field research trials conducted over time and space are needed to unravel the differences between aerial spray nozzle technologies for controlling weed populations in Texas farmlands. Full article
(This article belongs to the Section Weed Science and Weed Management)
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Article
Evaluation of Soil Water Content Measurements with Capacitance Probes to Support Irrigation Scheduling in a “Red Beaut” Japanese Plum Orchard
Agronomy 2020, 10(11), 1757; https://doi.org/10.3390/agronomy10111757 - 12 Nov 2020
Abstract
Advances in electromagnetic sensor technologies in recent years have made automated irrigation scheduling a reality through the use of state-of-the-art soil moisture sensing devices. However, correct sensor positioning and interpretation of the measurements are key to the successful implementation of these management systems. [...] Read more.
Advances in electromagnetic sensor technologies in recent years have made automated irrigation scheduling a reality through the use of state-of-the-art soil moisture sensing devices. However, correct sensor positioning and interpretation of the measurements are key to the successful implementation of these management systems. The aim of this study is to establish guidelines for soil moisture sensor placement to support irrigation scheduling, taking into account the physiological response of the plant. The experimental work was carried out in Vegas Bajas del Guadiana (Extremadura, Spain) on a drip-irrigated experimental orchard of the early-maturing Japanese plum cultivar “Red Beaut”. Two irrigation treatments were established: control and drying. The control treatment was scheduled to cover crop water needs. In the drying treatment, the fruit trees were irrigated as in control, except in certain periods (preharvest and postharvest) in which irrigation was suspended (drying cycles). Over 3 years (2015–2017), a series of plant parameters were analyzed in relation to the measurements provided by a battery of frequency domain reflectometry probes installed in different positions with respect to tree and dripper: midday stem water potential (Ψstem), sap flow, leaf stomatal conductance, net leaf photosynthesis and daily fraction of intercepted photosynthetically active radiation. After making a comparison of these measurements as indicators of plant water status, Ψstem was found to be the physiological parameter that detected water stress earliest. The drying cycles were very useful to select the probe positions that provided the best information for irrigation management and to establish a threshold in the different phases of the crop below which detrimental effects could be caused to the crop. With respect to the probes located closest to the drippers, a drop in the relative soil water content (RSWC) below 0.2 would not be advisable for “non-stress” scheduling in the preharvest period. When no deficit irrigation strategies are applied in the postharvest period, the criteria are similar to those of preharvest. However, the probes located between the dripper at 0.15 and 0.30 m depth provide information on moderate water stress if the RSWC values falls below 0.2. The severe tree water stress was detected below 0.1 RSWC in probes located at 60 cm depth from this same position. Full article
(This article belongs to the Special Issue Optimizing Plant Water Use Efficiency for a Sustainable Environment)
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Article
A Remote Sensing-Based Approach to Management Zone Delineation in Small Scale Farming Systems
Agronomy 2020, 10(11), 1767; https://doi.org/10.3390/agronomy10111767 - 12 Nov 2020
Cited by 1
Abstract
Small-scale farms represent about 80% of the farming area of China, in a context where they need to produce economic and environmentally sustainable food. The objective of this work was to define management zone (MZs) for a village by comparing the use of [...] Read more.
Small-scale farms represent about 80% of the farming area of China, in a context where they need to produce economic and environmentally sustainable food. The objective of this work was to define management zone (MZs) for a village by comparing the use of crop yield proxies derived from historical satellite images with soil information derived from remote sensing, and the integration of these two data sources. The village chosen for the study was Wangzhuang village in Quzhou County in the North China Plain (NCP) (30°51′55″ N; 115°02′06″ E). The village was comprised of 540 fields covering approximately 177 ha. The subdivision of the village into three or four zones was considered to be the most practical for the NCP villages because it is easier to manage many fields within a few zones rather than individually in situations where low mechanization is the norm. Management zones defined using Landsat satellite data for estimation of the Green Normalized Vegetation Index (GNDVI) was a reasonable predictor (up to 45%) of measured variation in soil nitrogen (N) and organic carbon (OC). The approach used in this study works reasonably well with minimum data but, in order to improve crop management (e.g., sowing dates, fertilization), a simple decision support system (DSS) should be developed in order to integrate MZs and agronomic prescriptions. Full article
(This article belongs to the Special Issue Site-Specific Nutrient Management)
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Article
Productive and Environmental Consequences of Sixteen Years of Unbalanced Fertilization with Nitrogen and Phosphorus—Trials in Poland with Oilseed Rape, Wheat, Maize and Barley
Agronomy 2020, 10(11), 1747; https://doi.org/10.3390/agronomy10111747 - 10 Nov 2020
Abstract
Two factorial field experiments were carried out between 2003 and 2018 in the Experimental Stations in Eastern and Western Poland using four crop rotations with winter oilseed rape, winter wheat, maize and spring barley. The initial value of phosphorus (P) in Grabów soil [...] Read more.
Two factorial field experiments were carried out between 2003 and 2018 in the Experimental Stations in Eastern and Western Poland using four crop rotations with winter oilseed rape, winter wheat, maize and spring barley. The initial value of phosphorus (P) in Grabów soil was 69.8 mg P·kg−1 soil and in Baborówko soil it was 111.3 mg P·kg−1 soil (Egner-Riehm Double-Lactate DL). P fertilizer was added annually at 39 kg P·ha−1 under winter oilseed rape, 35 kg P·ha−1 under maize and 31 kg P·ha−1 under wheat and barley using superphosphate and nitrogen (N), which was added at five levels (30–250 kg N·ha−1) per year as ammonium nitrate in addition to controls with no added fertilizer. Through the several years of the experiment, P fertilizer had no effect on crop N use efficiency (NUE) nor crop productivity. There was significant soil P mining particularly in the high-N fertilizer trials causing a reduction in the content of available soil P by up to 35%. This work recommends that, based on soil P analysis, P fertilizer should not be added to high-P soils. This practice may continue uninterrupted for several years (16 in this case) until the excess soil P has been reduced. This mechanism of removal of “legacy” P from soil has major implications in reducing runoff P into the Baltic Sea drainage area and other water bodies. Full article
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Article
Gene Expression in 1-Methylcyclopropene (1-MCP) Treated Tomatoes during Pre-Climacteric Ripening Suggests Shared Regulation of Methionine Biosynthesis, Ethylene Production and Respiration
Agronomy 2020, 10(11), 1669; https://doi.org/10.3390/agronomy10111669 - 29 Oct 2020
Cited by 1
Abstract
The physiology of fruit ripening is defined as either ‘climacteric’ or ‘non-climacteric’. In climacteric fruit respiration during ripening increases until it reaches a peak, which is accompanied by an increase in autocatalytic ethylene production, whereas the respiration of non-climacteric fruit does not increase [...] Read more.
The physiology of fruit ripening is defined as either ‘climacteric’ or ‘non-climacteric’. In climacteric fruit respiration during ripening increases until it reaches a peak, which is accompanied by an increase in autocatalytic ethylene production, whereas the respiration of non-climacteric fruit does not increase and they have no requirement for ethylene to complete their ripening. In an attempt to gain further insight into the involvement of autocatalytic ethylene production with the climacteric rise in respiration, tomato fruit were harvested at three defined stages of maturity prior to the climacteric peak (mature green, breaker, and early orange) and immediately exposed to the gaseous molecule 1-methylcyclopropene (1-MCP). The gene expression profile at each of these stages was monitored after 24 h, using an Affymetrix tomato microarray chip. This approach enabled us to identify ethylene responsive genes that are commonly regulated at early stages of ripening, as well as new candidate genes. In addition, 1-MCP treatment affected the levels of metabolites related to methionine biosynthesis. Methionine feeds climacteric ethylene production and we found that promotors of the genes of enzymes that catalyze the production of homoserine and homocysteine (aspartokinase/homoserine dehydrogenases and cystathionine beta lyase, respectively), precursors in the methionine pathway, contain the AtSR1 binding motif. This binding motif is recognized by ethylene activated transcription factors, hence indicating a role for ethylene in methionine synthesis during early ripening, explaining the autocatalytic ethylene production during subsequent ripening stages. Full article
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Article
Evaluating the Impact of Alternative Cropping Systems on Groundwater Consumption and Nitrate Leaching in the Piedmont Area of the North China Plain
Agronomy 2020, 10(11), 1635; https://doi.org/10.3390/agronomy10111635 - 23 Oct 2020
Abstract
The overexploitation of groundwater and the excessive application of nitrogen (N) fertilizer under the intensive double cropping system are responsible for the groundwater level decline and potential contamination in the North China Plain (NCP). Alternative cropping systems have the potential to alleviate current [...] Read more.
The overexploitation of groundwater and the excessive application of nitrogen (N) fertilizer under the intensive double cropping system are responsible for the groundwater level decline and potential contamination in the North China Plain (NCP). Alternative cropping systems have the potential to alleviate current groundwater and N problems in the region, while there are limited studies simultaneously focusing on the impact of a change of cropping systems on crop yields, groundwater consumption, and N leaching. In this study, Field observed experiments of double-cropping system (i.e., winter wheat–summer maize) and mono-cropping system (early sowing maize) were used to calibrate and validate the Root Zone Water Quality Model (RZWQM2). Then, the validated RZWQM2 model was used to evaluate the long-term crop growth and environmental impact under the local winter wheat–summer maize rotation system with practical irrigation (WW-SM_pi) and auto-irrigation (WW-SM_ai), and three alternative cropping systems (single early maize, SEM; winter wheat–summer maize and single early maize, WW-SM-SEM; winter wheat-summer maize and double single early maize, WW-SM-2SEM). The net consumption of groundwater and N leaching under WW-SM_pi were 226.9 mm yr−1 and 79.7 kg ha−1 yr−1, respectively. Under the local rotation system, auto-irrigation could increase crop yields and N leaching. Compared with the WW-SM_ai, the alternative cropping systems, WW-SM-SEM, WW-SM-2SEM, and SEM, significantly decreased the net consumption of groundwater by 49.3%, 63.0%, and 97.8%, respectively (147.5–292.9 mm), and N leaching by 53.5%, 67.5%, and 89.6%, respectively (50.0–83.7 kg ha−1). However, the yields of the three alternative cropping systems were reduced by less than 30% (12.2%, 20.1%, and 29.7%, respectively). The simulated results indicated that appropriately decreasing the planting frequency of winter wheat is an effective approach to reduce groundwater overexploitation and N contamination with a relatively limited reduction in grain yields. The results could provide a scientific basis for cropping system adjustment in guaranteeing sustainable regional water and grain policy. Full article
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Article
Assessing Effect of Marker-Based Improvement of Maize Synthetics on Agronomic Performance, Carotenoid Content, Combining Ability and Heterosis
Agronomy 2020, 10(11), 1625; https://doi.org/10.3390/agronomy10111625 - 22 Oct 2020
Abstract
Vitamin A deficiency (VAD) is a serious problem in sub-Saharan Africa (SSA) and other parts of the world. Understanding the effect of marker-based improvement (MARS) of two maize synthetics (HGA and HGB) representing different heterotic groups on their agronomic performance, carotenoid content, and [...] Read more.
Vitamin A deficiency (VAD) is a serious problem in sub-Saharan Africa (SSA) and other parts of the world. Understanding the effect of marker-based improvement (MARS) of two maize synthetics (HGA and HGB) representing different heterotic groups on their agronomic performance, carotenoid content, and combining abilities could help identify suitable sources to develop divergent inbred lines for optimizing heterosis. This study involved three selection cycles each of the two synthetics and their nine varietal-cross hybrids together with a released check variety was conducted across four diverse locations in Nigeria in 2018 and 2019. Environment and hybrid effects were significant on grain yield and other agronomic traits as well as provitamin A content and other carotenoids. Genetic improvement per cycle of MARS in the parental synthetics was 15% for provitamin A, 25% for β-carotene and 26% for lutein in HGA and 4% for grain yield, 3% for zeaxanthin and 5% for α-carotene in HGB. Grain yield and agronomic traits of the two maize synthetics were controlled by additive and non-additive gene effects, while provitamin A content and other carotenoids were mainly controlled by additive gene effects. Some selection cycles which were high in grain yield and provitamin A content were identified as potential sources of new and divergent maize inbred lines in maize breeding programs. Some varietal-cross hybrids expressed significant mid-parent heterosis for grain yield and moderate mid-parent heterosis for provitamin A, β-carotene and xanthophylls. These hybrids could be commercialized at reasonable prices to small-scale farmers in rural areas that are most affected by vitamin A deficiency. Full article
(This article belongs to the Special Issue Cereal Biofortification: Strategies, Challenges and Benefits)
Article
Modelling and Prediction of Organic Carbon Dynamics in Arable Soils Based on a 62-Year Field Experiment in the Voronezh Region, European Russia
Agronomy 2020, 10(10), 1607; https://doi.org/10.3390/agronomy10101607 - 20 Oct 2020
Cited by 3
Abstract
Organic carbon (OC) accumulation in soil mitigates greenhouse gases emission and improves soil health. We aimed to quantify the dynamics of OC stock in soils and to justify technologies that allow annual increasing OC stock in the arable soil layer by 4‰. We [...] Read more.
Organic carbon (OC) accumulation in soil mitigates greenhouse gases emission and improves soil health. We aimed to quantify the dynamics of OC stock in soils and to justify technologies that allow annual increasing OC stock in the arable soil layer by 4‰. We based the study on a field experiment established in 1936 in the 9-field crop rotation with a fallow on Chernozem in European Russia. The RothC version 26.3 was used for the reproducing and forecasting OC dynamics. In all fertilizer applications at FYM background, there was a decrease in the OC stock with preferable loss of active OC, except the period 1964–1971 with 2–5‰ annual OC increase. The model estimated the annual C input necessary to maintain OC stock as 1900 kg·ha−1. For increasing OC stocks by 4‰ per year, one should raise input to 2400 kg·ha−1. The simulation was made for 2016–2090 using climate scenarios RCP4.5 and RCP8.5. Crop rotation without fallowing provided an initial increase of 3‰ and 6‰ of stocks in the RCP8.5 and RCP4.5 scenarios accordingly, followed by a loss in accumulated OC. Simulation demonstrates difficulties to increase OC concentration in Chernozems under intensive farming and potential capacity to rise OC stock through yield management. Full article
(This article belongs to the Special Issue Effects of Agricultural Management on Soil Properties and Health)
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Article
Can Control of Glyphosate Susceptible and Resistant Conyza sumatrensis Populations Be Dependent on the Herbicide Formulation or Adjuvants?
Agronomy 2020, 10(10), 1599; https://doi.org/10.3390/agronomy10101599 - 19 Oct 2020
Cited by 1
Abstract
In this work, we studied the effect of three glyphosate formulations (isopropylamine, ammonium and potassium salts) and two non-ionic adjuvants on the resistance response of two resistant (R1, R2) and one susceptible population of the highly invasive Asteraceae, Conyza sumatrensis, from Southern [...] Read more.
In this work, we studied the effect of three glyphosate formulations (isopropylamine, ammonium and potassium salts) and two non-ionic adjuvants on the resistance response of two resistant (R1, R2) and one susceptible population of the highly invasive Asteraceae, Conyza sumatrensis, from Southern France vineyards. Only in R1, an amino acid substitution (Pro106Thr) was found in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). The two adjuvants, in a similar fashion, significantly reduced GR50 values for every population and glyphosate formulation. Without adjuvants, glyphosate as potassium salt was the only formulation able to significantly reduce the GR50 values of every population. For every population, the two adjuvants improved, indistinguishably, leaf retention of the herbicidal solution and the potassium salt formulation led to the highest retention, both with and without the adjuvant added. Uptake responses paralleled those of retention and adjuvant addition was more effective in increasing foliar uptake of the lower performing formulations (isopropylamine and ammonium salts). The allocation pattern of glyphosate among plant compartments was only dependent on population, with R2 retaining most glyphosate in the treated leaf, clearly suggesting the occurrence of a Non-Target Site Resistance (NTSR) mechanism. Results indicate that control of weed populations possessing NTSR mechanisms of resistance to glyphosate may be improved through adequate selection of formulation and adjuvant use. Full article
(This article belongs to the Special Issue Weed Management & Sustainable Agriculture)
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Article
Long-Term Effects of the Application of Urban Waste Compost and Other Organic Amendments on Solanum tuberosum L.
Agronomy 2020, 10(10), 1575; https://doi.org/10.3390/agronomy10101575 - 15 Oct 2020
Cited by 4
Abstract
Background: In a Mediterranean agrosystem of low productivity, a study was carried out on the effects of municipal solid waste compost (MSWC) compared to other organic and inorganic amendments on the production, quality and yield of three potato varieties (Solanum tuberosum L.) [...] Read more.
Background: In a Mediterranean agrosystem of low productivity, a study was carried out on the effects of municipal solid waste compost (MSWC) compared to other organic and inorganic amendments on the production, quality and yield of three potato varieties (Solanum tuberosum L.) and an advanced clone. Method: Simultaneously, the agronomic and nutritional parameters of the potato crop, the degree of bioavailability and the possible risks of heavy metal contamination were studied. Results: Two stages are observed in the yield and content of macro, micronutrients and heavy metals. The addition of all amendments and especially that of urban waste compost increased potato production and the content of macronutrients, micronutrients and heavy metals in the soils of all varieties, showing a progressive accumulation in tubers. Nevertheless, the performance is not maintained over time with a notable decrease during the second stage of its application. Conclusion: Highlighting the potato clone A7677 not only in its performance but also in the concentration of iron, zinc, copper, essential micronutrients for human consumption and especially for populations deficient in these trace elements. Full article
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Article
Development of Pretreatment Strategies for the Fractionation of Hazelnut Shells in the Scope of Biorefinery
Agronomy 2020, 10(10), 1568; https://doi.org/10.3390/agronomy10101568 - 14 Oct 2020
Cited by 2
Abstract
Hazelnut shells are an important waste from the hazelnut processing industry that could be valorized in a multi-product biorefinery. Individual or combined pretreatments may be integrated in processes enabling the integral fractionation of biomass. In this study, fractionation methods based on alkaline, alkaline-organosolv, [...] Read more.
Hazelnut shells are an important waste from the hazelnut processing industry that could be valorized in a multi-product biorefinery. Individual or combined pretreatments may be integrated in processes enabling the integral fractionation of biomass. In this study, fractionation methods based on alkaline, alkaline-organosolv, organosolv, or acid-catalyzed organosolv treatments were applied to raw or autohydrolyzed hazelnut shells. A comparative analysis of results confirmed that the highest lignin removal was achieved with the acid-catalyzed organosolv delignification, which also allowed limited cellulose losses. When this treatment was applied to raw hazelnut shells, 65.3% of the lignin was removed, valuable hemicellulose-derived products were obtained, and the cellulose content of the processed solids increased up to 54%. Autohydrolysis of hazelnut shells resulted in the partial solubilization of hemicelluloses (mainly in the form of soluble oligosaccharides). Consecutive stages of autohydrolysis and acid-catalyzed organosolv delignification resulted in 47.9% lignin removal, yielding solids of increased cellulose content (55.4%) and very low content of residual hemicelluloses. The suitability of selected delignified and autohydrolyzed-delignified hazelnut shells as substrates for enzymatic hydrolysis was assessed in additional experiments. The most susceptible substrates (from acid-catalyzed organosolv treatments) reached 74.2% cellulose conversion into glucose, with a concentration of 28.52 g glucose/L. Full article
(This article belongs to the Special Issue Pretreatment and Bioconversion of Crop Residues)
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Article
Osmo-Priming with Seaweed Extracts Enhances Yield of Salt-Stressed Tomato Plants
Agronomy 2020, 10(10), 1559; https://doi.org/10.3390/agronomy10101559 - 13 Oct 2020
Cited by 4
Abstract
Salinization of agricultural land is an expanding phenomenon, which requires a multi-level strategy to counteract its deleterious effects on crop yield and quality. Plant biostimulants are increasingly used in agriculture with multiple purposes, including protection against abiotic stresses such as drought and salinity. [...] Read more.
Salinization of agricultural land is an expanding phenomenon, which requires a multi-level strategy to counteract its deleterious effects on crop yield and quality. Plant biostimulants are increasingly used in agriculture with multiple purposes, including protection against abiotic stresses such as drought and salinity. The complex nature of plant biostimulants, however, makes it difficult to establish a cause–effect relationship between the composition of the commercial product and its expected effects. Here, we demonstrate that field applications of two algal derivatives (Rygex, R and Super Fifty, SU) cause a 26% reduction in shoot biomass and a remodulation of the root-to-shoot ratio under moderately saline irrigation (6.3 dS m−1). Moreover, plants treated with the two algal derivatives showed lower leaf water potential and improved water use efficiency under control conditions, suggesting an osmo-priming effect by these two products. These pre-adaptation responses increased tomato yield by 49% (R) and 70% (SU) regardless of the salinity level, with a remarkable reallocation of the biomass toward the fruits. Overall, our results suggest that the application of these two biostimulants can be useful in the open field to protect tomato plants from osmotic stress due to seasonal salinization, a phenomenon that typically occurs in arid and semi-arid environments. Full article
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Article
Phosphorus Uptake and Growth of Wild-Type Barley and Its Root-Hairless Mutant Cultured in Buffered-and Non-Buffered-P Solutions
Agronomy 2020, 10(10), 1556; https://doi.org/10.3390/agronomy10101556 - 13 Oct 2020
Cited by 1
Abstract
Root hairs play an important role in phosphorus (P) nutrition of plants. To better understand the relationship between root hairs and P acquisition efficiency (PAE) in barley, experiments were conducted with the wild-type barley (cv. ’Pallas’) and its root-hairless mutant (brb). [...] Read more.
Root hairs play an important role in phosphorus (P) nutrition of plants. To better understand the relationship between root hairs and P acquisition efficiency (PAE) in barley, experiments were conducted with the wild-type barley (cv. ’Pallas’) and its root-hairless mutant (brb). A hydroponic split-root system was used to supply P as Ca3(PO4)2 (tri-calcium phosphate, TCP) to one-half and other nutrients to the other half of the root system. Using TCP as a sole P source can simulate a soil solution with buffered low P concentration in hydroponics to induce prolific root hair growth. Root morphology, plant growth, and P uptake efficiency were measured with 50 mg L−1 TCP supplied to the roots in the split-root system and 0, 35, or 1000 μM NaH2PO4 in a non-split-root hydroponic system. The wild-type plants developed root hairs, but they did not contribute to the significant genotypic differences in the P uptake rate when a soluble P source was supplied in the non-split root system, indicating that root hair formation does not contribute to P uptake in a non-split root solution. On the other hand, when grown in a split-root system with one-half of the roots supplied with TCP, the wild-type showed 1.25-fold greater P uptake than the root hairless mutant. This study provides evidence that root hairs play an essential role in plant P uptake when P bioavailability is limited in the root zone. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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Article
Introgression of the Afila Gene into Climbing Garden Pea (Pisum sativum L.)
Agronomy 2020, 10(10), 1537; https://doi.org/10.3390/agronomy10101537 - 10 Oct 2020
Cited by 1
Abstract
The pea (Pisum sativum L.) is one of the most important crops in temperate agriculture around the world. In the tropics, highland production is also common with multiple harvests of nearly mature seeds from climbing plant types on trellises. While the leafless [...] Read more.
The pea (Pisum sativum L.) is one of the most important crops in temperate agriculture around the world. In the tropics, highland production is also common with multiple harvests of nearly mature seeds from climbing plant types on trellises. While the leafless variant caused by the afila gene is widely used in developing row-cropped field peas in Europe, its use for trellised garden peas has not been reported. In this study we describe a pea breeding program for a high-elevation tropical environment in the Department of Nariño in Colombia, where over 16,000 hectares of the crop are produced. The most widespread climbing varieties in the region are ‘Andina’ and ‘Sindamanoy’, both of which have high-biomass architecture with abundant foliage. They are prone to many diseases, but preferred by farmers given their long production season. This plant type is expensive to trellis, with wooden posts and plastic strings used for vine staking constituting 52% of production costs. The afila trait could reduce these costs by creating interlocking plants as they do in field peas. Therefore, our goal for this research was to develop a rapid breeding method to introduce the recessive afila gene, which replaces leaves with tendrils, into the two commercial varieties used as recurrent parents (RPs) with three donor parents (DPs)—‘Dove’, ‘ILS3575′ and ‘ILS3568′—and to measure the effect on plant height (PH) and yield potential. Our hypothesis was that the afila gene would not cause linkage drag while obtaining a leafless climbing pea variety. Backcrossing was conducted without selfing for two generations and plants were selected to recover recurrent parent characteristics. Chi-square tests showed a ratio of 15 normal leaved to one afila leaved in the BC2F2 plants, and 31:1 in the BC3F2 generation. Selecting in the last of these generations permitted a discovery of tall climbing plants that were similar to those preferred commercially, but with the stable leafless afila. The method saved two seasons compared to the traditional method of progeny testing before each backcross cycle; the peas reached the BC2F2 generation in five seasons and the BC3F2 in seven seasons. This is advantageous with trellised peas that normally require half a year to reach maturity. Leafless garden peas containing the afila gene were of the same height as recurrent parents and, by the third backcross, were equally productive, without the high biomass found in the traditional donor varieties. The value of the afila gene and the direct backcrossing scheme is discussed in terms of garden pea improvement and crop breeding. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Estimating Organ Contribution to Grain Filling and Potential for Source Upregulation in Wheat Cultivars with a Contrasting Source–Sink Balance
Agronomy 2020, 10(10), 1527; https://doi.org/10.3390/agronomy10101527 - 08 Oct 2020
Cited by 2
Abstract
Grain filling may be limited by the joint source and sink capacity in modern wheat cultivars, indicating a need to research the co-limitation of yield by both photosynthesis and the number and potential size of grains. The extent to which the post-anthesis source [...] Read more.
Grain filling may be limited by the joint source and sink capacity in modern wheat cultivars, indicating a need to research the co-limitation of yield by both photosynthesis and the number and potential size of grains. The extent to which the post-anthesis source may be limiting final grain size can be estimated by partial degraining of spikes, while defoliation and shading treatments can be useful to estimate if any excess photosynthetic capacity exists. In the current study, degraining was applied to a set of 26 elite spring wheat cultivars from the International Maize and Wheat Improvement Center (CIMMYT)’s core germplasm (CIMCOG) panel, while lamina defoliation and shading through stem-and-leaf-sheath covering treatments were applied to a subset of the same cultivars. Responses to source treatments in grain weight, pre-anthesis reserve contribution to grain weight, dry-matter translocation efficiency, and flag-leaf and spike photosynthetic rate were measured and compared to an unmanipulated control treatment. Grain weight responses to degraining among cultivars ranged from no response to increases of 28%, suggesting a range of responses from sink limitation, to probable source and sink co-limitation of grain growth. Grain weight’s response to degraining increased linearly with the years of cultivar release from 1966 to 2009, indicating that the current highest yield potential CIMMYT spring wheats have a co-limitation of grain growth by source and sink. This may have been due to an increase in grain sink strength with years of cultivar release with no commensurate increase in post-anthesis source capacity. The relatively low decreases in grain weight with defoliation compared to decreases in light interception by defoliation indicated that sink limitation was still likely predominating in the cultivars with co-limitation. The stem-and-leaf-sheath covering treatment decreased grain weight by nearly 10%, indicating that stem-and-leafsheath photosynthesis plays a key role in grain growth during grain filling. In addition, pre-anthesis reserve contribution to grain weight was increased by ca. 50% in response to lamina defoliation. Our results showed that increasing the post-anthesis source capacity, through increases in stem-and-leaf-sheath photosynthetic rate during grain filling and pre-anthesis reserve contribution to grain weight, is an important objective in enhancing yield potential in wheat through maintaining a source–sink balance. Full article
(This article belongs to the Special Issue Photosynthetic Performance and Water-Use-Efficiency in Grasses)
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Article
Screening of Popcorn Genotypes for Drought Tolerance Using Canonical Correlations
Agronomy 2020, 10(10), 1519; https://doi.org/10.3390/agronomy10101519 - 06 Oct 2020
Abstract
Getting around the damage caused by drought is a worldwide challenge, particularly in Brazil, given that economy is based on agricultural activities, including popcorn growing. The purpose of this study was to evaluate popcorn inbred lines under water stressed (WS) and well-watered (WW) [...] Read more.
Getting around the damage caused by drought is a worldwide challenge, particularly in Brazil, given that economy is based on agricultural activities, including popcorn growing. The purpose of this study was to evaluate popcorn inbred lines under water stressed (WS) and well-watered (WW) conditions regarding agronomic attributes, root morphology, and leaf “greenness” index (SPAD index), besides investigating the viability of indirect selection by canonical correlations (CC) of grain yield (GY) and popping expansion (PE). Seven agronomic, six morphological root traits were evaluated and SPAD index at five different dates during grain filling. The WS (−29% less water than WW) affected significantly the GY (−55%), PE (−28%), increased the brace and crown root density, and more vertically oriented the brace and crown angles. Higher SPAD index is associated with a higher yield, and these measures were the only ones with no significant genotype × water condition interaction, which may render concomitant selection for WS and WW easier. For associating the corrections of the different traits, CC proved to have better potential than simple correlations. Thus, the evaluation of SPAD index at 29 days after the anthesis showed the best CC, and based on the previous results of SPAD index, may be used regardless of the water condition. Full article
(This article belongs to the Special Issue Optimizing Plant Water Use Efficiency for a Sustainable Environment)
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Article
Chlorophyll-a Fluorescence Analysis Reveals Differential Response of Photosynthetic Machinery in Melatonin-Treated Oat Plants Exposed to Osmotic Stress
Agronomy 2020, 10(10), 1520; https://doi.org/10.3390/agronomy10101520 - 06 Oct 2020
Abstract
In this study, the effects of melatonin-induced enhancement on the principal photosynthetic parameters and antioxidant machinery were investigated in Avena sativa (oat) plants exposed to polyethylene glycol (PEG)-induced osmotic stress. The parameters of growth, chlorophyll content, stomatal conductance, proline accumulation, lipid peroxidation, and [...] Read more.
In this study, the effects of melatonin-induced enhancement on the principal photosynthetic parameters and antioxidant machinery were investigated in Avena sativa (oat) plants exposed to polyethylene glycol (PEG)-induced osmotic stress. The parameters of growth, chlorophyll content, stomatal conductance, proline accumulation, lipid peroxidation, and electrolyte leakage showed noteworthy improvements between the groups. Melatonin treatment caused upregulation of the genes that encode the three major antioxidant enzymes: ascorbate peroxidase (APX), superoxide dismutase (SOD) and catalase (CAT). Chlorophyll-a fluorescence kinetic analyses revealed that melatonin treatment improved performance indices (PIABS and PItotal), quantum yields, and efficiencies of photosystem II (PSII) in oat plants subjected to PEG-induced osmotic stress. Furthermore, upregulation of five genes (PsbA, PsbB, PsbC, PsbD, and PsbO) that encode the core proteins of PSII implied melatonin exerted a positive influence on photosynthesis under conditions of osmotic stress. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Identification of Opportunities for Applying the Circular Economy to Intensive Agriculture in Almería (South-East Spain)
Agronomy 2020, 10(10), 1499; https://doi.org/10.3390/agronomy10101499 - 01 Oct 2020
Cited by 5
Abstract
The use of intensive high-yield agricultural systems has proved to be a feasible alternative to traditional systems as they able to meet the objective of guaranteeing long-term sustainability in the supply of food. In order to implement these systems, it is necessary to [...] Read more.
The use of intensive high-yield agricultural systems has proved to be a feasible alternative to traditional systems as they able to meet the objective of guaranteeing long-term sustainability in the supply of food. In order to implement these systems, it is necessary to replace the traditional model of “extract-use-consume-dispose” with a model based on the principles of the Circular Economy (CE), optimizing the use of resources and minimizing the generation of waste. Almería has become a paradigm of this type of high-yield agricultural system, with the largest concentration of greenhouses in the world. This study analyses the opportunities that the CE can offer the intensive agriculture sector in Almería in order to obtain long-term sustainability. The results show a wide variety of alternatives, both on an agricultural exploitation level and in the case of the product packaging and wholesale centers. The priority areas of action are waste management, the prevention of product waste and the improvement in the efficiency of the use of water and energy. The principal limitations for adopting circular practices are the large investment required, the limited transfer of knowledge between the different users and the lack of sufficient support from the government and the sector. Full article
(This article belongs to the Special Issue Greenhouse Technology)
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Article
Confirmation and Characterization of the First Case of Acetolactate Synthase (ALS)-Inhibitor—Resistant Wild Buckwheat (Polygonum convolvulus L.) in the United States
Agronomy 2020, 10(10), 1496; https://doi.org/10.3390/agronomy10101496 - 01 Oct 2020
Cited by 1
Abstract
Wild buckwheat (Polygonum convolvulus L.) is a problem weed and ALS-inhibitors (e.g., chlorsulfuron) are commonly used for its management. Recently, a population of wild buckwheat (KSW-R) uncontrolled with ALS-inhibitors was found in a wheat field in Kansas, USA. The objectives of this [...] Read more.
Wild buckwheat (Polygonum convolvulus L.) is a problem weed and ALS-inhibitors (e.g., chlorsulfuron) are commonly used for its management. Recently, a population of wild buckwheat (KSW-R) uncontrolled with ALS-inhibitors was found in a wheat field in Kansas, USA. The objectives of this research were to determine the level and mechanism of resistance to chlorsulfuron and cross resistance to other ALS-inhibitors in the KSW-R population. In response to chlorsulfuron rates ranging from 0 to 16x (x = 18 g ai/ha), the KSW-R wild buckwheat was found >100-fold more resistant compared to a known ALS-inhibitor susceptible (KSW-S) wild buckwheat. Also, >90% of KSW-R plants survived field recommended rates of sulfonylurea but not imidazolinone family of ALS-inhibitors. A portion of the ALS gene covering all previously reported mutations known to bestow resistance to ALS-inhibitors was sequenced from both KSW-R and KSW-S plants. The Pro-197-Ser substitution that confers resistance to the sulfonylurea herbicides was found in KSW-R plants. Our results support the evolution of high level of chlorsulfuron resistance as a result of a mutation in the ALS-gene in KSW-R buckwheat. This is the first case of resistance to any herbicides in wild buckwheat in the US. Full article
(This article belongs to the Special Issue Herbicide Resistance in Weed Management)
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Article
Effects of Root Temperature on the Plant Growth and Food Quality of Chinese Broccoli (Brassica oleracea var. alboglabra Bailey)
Agronomy 2020, 10(5), 702; https://doi.org/10.3390/agronomy10050702 - 14 May 2020
Cited by 4
Abstract
Root temperature has long been considered an essential environmental factor influencing the plant’s physiology. However, little is known about the effect of root temperature on the quality of the food produced by the plant, especially that of horticultural crops. To fill this gap, [...] Read more.
Root temperature has long been considered an essential environmental factor influencing the plant’s physiology. However, little is known about the effect of root temperature on the quality of the food produced by the plant, especially that of horticultural crops. To fill this gap, two independent root cooling experiments (15 °C vs. 20 °C and 10 °C vs. 20 °C) were conducted in autumn 2017 and spring 2018 in hydroponics with Chinese broccoli (Brassica oleracea var. alboglabra Bailey) under greenhouse conditions. The aim was to investigate the effect of root temperature on plant growth (biomass, height, yield) and food quality (soluble sugars, total chlorophyll, starch, minerals, glucosinolates). A negative impact on shoot growth parameters (yield, shoot biomass) was detected by lowering the root temperature to 10 °C. Chinese broccoli showed no response to 15 °C root temperature, except for an increase in root biomass. Low root temperature was in general associated with a higher concentration of soluble sugars and total chlorophyll, but lower mineral levels in stems and leaves. Ten individual glucosinolates were identified in the stems and leaves, including six aliphatic and four indolic glucosinolates. Increased levels of neoglucobrassicin in leaves tracked root cooling more closely in both experiments. Reduction of root temperature by cooling could be a potential method to improve certain quality characters of Chinese broccoli, including sugar and glucosinolate levels, although at the expense of shoot biomass. Full article
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Article
The Impact of Herbicide Application and Defoliation on Barley Grass (Hordeum murinum subsp. glaucum) Management in Mixed Pasture Legumes
Agronomy 2020, 10(5), 671; https://doi.org/10.3390/agronomy10050671 - 11 May 2020
Cited by 1
Abstract
Barley grass (Hordeum murinum subsp. glaucum.) is an annual weed associated with grain revenue loss and sheep carcass damage in southern Australia. Increasing herbicide resistance led to a recent investigation into effective integrated weed management strategies for barley grass in southern [...] Read more.
Barley grass (Hordeum murinum subsp. glaucum.) is an annual weed associated with grain revenue loss and sheep carcass damage in southern Australia. Increasing herbicide resistance led to a recent investigation into effective integrated weed management strategies for barley grass in southern Australia. Field studies in Wagga Wagga, New South Wales (NSW) during 2016 and 2017 examined the effect of post-emergent herbicide applications and strategic defoliation by mowing on barley grass survival and seed production in a mixed legume pasture. Statistically significant differences between herbicide-only treatments in both years showed propaquizafop to be more than 98% effective in reducing barley grass survival and seed production. Paraquat was not effective in controlling barley grass (58% efficacy), but led to a 36% and 63.5% decrease in clover and other weed biomass, respectively, after 12 months and increased lucerne biomass by over three-fold after 24 months. A single repeated mowing treatment resulted in a 46% decline in barley grass seedling emergence after 12 months and, when integrated with herbicide applications, reduced other weed biomass after 24 months by 95%. Resistance to acetyl-CoA carboxylase (ACCase)-inhibiting herbicides observed in local barley grass populations led to additional and more focused investigation comparing the efficacy of other pre- and post-emergent herbicides for barley grass management in legume pastures. Haloxyfop-R + simazine or paraquat, applied at early tillering stage, were most efficacious in reducing barley grass survival and fecundity. Impact of defoliation timing and frequency on barley grass seedlings was also evaluated at various population densities, highlighting the efficacy of repeated post-inflorescence defoliations in reducing plant survival and seed production. Results highlight the importance of optimal environmental conditions and application timing in achieving efficacious control of barley grass and improving pasture growth and biomass accumulation. Full article
(This article belongs to the Special Issue Herbicide Resistance in Weed Management)
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Article
Effect of Row Spacing, Sowing Density, and Harvest Time on Floret Yield and Yield Components of Two Safflower Cultivars Grown in Southwestern Germany
Agronomy 2020, 10(5), 664; https://doi.org/10.3390/agronomy10050664 - 08 May 2020
Cited by 3
Abstract
The current demand for safflower florets (Carthamus tinctorius L.) in the food-coloring industry, especially in Europe, is rising. The present production, mainly located in China, is not sufficient. Unlike for the production of seeds, there are currently no recommendations for the cultivation [...] Read more.
The current demand for safflower florets (Carthamus tinctorius L.) in the food-coloring industry, especially in Europe, is rising. The present production, mainly located in China, is not sufficient. Unlike for the production of seeds, there are currently no recommendations for the cultivation of safflower for floret production in Germany. Therefore, field experiments were conducted at the experimental station Ihinger Hof, Southwestern Germany, in 2017 and 2018. The aim was to evaluate yield and yield parameters, such as number of capitula, floret yield, and carthamidin content for (i) two cultivars grown with (ii) two row spacing (12 and 33 cm) using (iii) two sowing densities (40 and 75 plants m−2), and (iv) five harvest dates. Results showed that lower sowing densities resulted in a significantly larger number of branches and capitula per plant and higher yields of florets and carthamidin. Harvesting two to three weeks after flowering resulted in the significantly highest floret and carthamidin yields. More capitula per plant, higher carthamidin contents, and higher floret and carthamidin yields were obtained with the Chinese cultivar. In general, yields of flowering florets (2.30–468.96 kg ha−1), carthamidin contents (2.53–8.29%), and carthamidin yields (0.04–37.86 kg ha−1) were comparable to or higher than in other studies. In conclusion, this study showed that safflower has great potential for the production of florets in Southwest Germany, for the food-color industry. Full article
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Article
Exploring the Genetic Architecture of Root-Related Traits in Mediterranean Bread Wheat Landraces by Genome-Wide Association Analysis
Agronomy 2020, 10(5), 613; https://doi.org/10.3390/agronomy10050613 - 25 Apr 2020
Cited by 4
Abstract
Background: Roots are essential for drought adaptation because of their involvement in water and nutrient uptake. As the study of the root system architecture (RSA) is costly and time-consuming, it is not generally considered in breeding programs. Thus, the identification of molecular markers [...] Read more.
Background: Roots are essential for drought adaptation because of their involvement in water and nutrient uptake. As the study of the root system architecture (RSA) is costly and time-consuming, it is not generally considered in breeding programs. Thus, the identification of molecular markers linked to RSA traits is of special interest to the breeding community. The reported correlation between the RSA of seedlings and adult plants simplifies its assessment. Methods: In this study, a panel of 170 bread wheat landraces from 24 Mediterranean countries was used to identify molecular markers associated with the seminal RSA and related traits: seminal root angle, total root number, root dry weight, seed weight and shoot length, and grain yield (GY). Results: A genome-wide association study identified 135 marker-trait associations explaining 6% to 15% of the phenotypic variances for root related traits and 112 for GY. Fifteen QTL hotspots were identified as the most important for controlling root trait variation and were shown to include 31 candidate genes related to RSA traits, seed size, root development, and abiotic stress tolerance (mainly drought). Co-location for root related traits and GY was found in 17 genome regions. In addition, only four out of the fifteen QTL hotspots were reported previously. Conclusions: The variability found in the Mediterranean wheat landraces is a valuable source of root traits to introgress into adapted phenotypes through marker-assisted breeding. The study reveals new loci affecting root development in wheat. Full article
(This article belongs to the Special Issue Molecular Marker Technology for Crop Improvement)
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