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 readers, or important in the respective research area. 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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17 pages, 1360 KiB  
Article
Effect of Biochar Application and Re-Application on Soil Bulk Density, Porosity, Saturated Hydraulic Conductivity, Water Content and Soil Water Availability in a Silty Loam Haplic Luvisol
by Lucia Toková, Dušan Igaz, Ján Horák and Elena Aydin
Agronomy 2020, 10(7), 1005; https://doi.org/10.3390/agronomy10071005 - 13 Jul 2020
Cited by 67 | Viewed by 5919
Abstract
Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk [...] Read more.
Due to climate change the productive agricultural sectors have started to face various challenges, such as soil drought. Biochar is studied as a promising soil amendment. We studied the effect of a former biochar application (in 2014) and re-application (in 2018) on bulk density, porosity, saturated hydraulic conductivity, soil water content and selected soil water constants at the experimental site in Dolná Malanta (Slovakia) in 2019. Biochar was applied and re-applied at the rates of 0, 10 and 20 t ha−1. Nitrogen fertilizer was applied annually at application levels N0, N1 and N2. In 2019, these levels were represented by the doses of 0, 108 and 162 kg N ha−1, respectively. We found that biochar applied at 20 t ha−1 without fertilizer significantly reduced bulk density by 12% and increased porosity by 12%. During the dry period, a relative increase in soil water content was observed at all biochar treatments—the largest after re-application of biochar at a dose of 20 t ha−1 at all fertilization levels. The biochar application also significantly increased plant available water. We suppose that change in the soil structure following a biochar amendment was one of the main reasons of our observations. Full article
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14 pages, 2847 KiB  
Article
Supplementary LED Interlighting Improves Yield and Precocity of Greenhouse Tomatoes in the Mediterranean
by Ivan Paucek, Giuseppina Pennisi, Alessandro Pistillo, Elisa Appolloni, Andrea Crepaldi, Barbara Calegari, Francesco Spinelli, Antonio Cellini, Xavier Gabarrell, Francesco Orsini and Giorgio Gianquinto
Agronomy 2020, 10(7), 1002; https://doi.org/10.3390/agronomy10071002 - 12 Jul 2020
Cited by 55 | Viewed by 9153
Abstract
In Northern Europe, the use of light–emitting diodes (LEDs) is widely adopted in protected horticulture, enabling to enhance plant growth by ensuring needed radiative fluxes throughout seasons. Contrarily, the use of artificial lighting in Mediterranean greenhouse still finds limited applications. In this study, [...] Read more.
In Northern Europe, the use of light–emitting diodes (LEDs) is widely adopted in protected horticulture, enabling to enhance plant growth by ensuring needed radiative fluxes throughout seasons. Contrarily, the use of artificial lighting in Mediterranean greenhouse still finds limited applications. In this study, the effects of supplemental LED interlighting on vegetative development, fruit growth, yield, and fruit quality of high-wire tomato plants (Solanum lycopersicum L. cv. ‘Siranzo’) during spring and summer season were addressed in a hydroponic greenhouse in Italy. Plants were either grown under natural solar radiation (control), or by adding supplemental LED interlighting. LED treatment featured red (R) and blue (B) light (RB ratio of 3) and a photosynthetic photon flux density of 170 µmol m−2 s−1 for 16 h d−1. Supplemental LED interlighting enhanced yield as a result of increased fruit weight and dimension. While no effects on soluble solids content and fruit color at harvesting were observed, supplemental LED interlighting accelerated ripening by one week in spring and two weeks in summer and this also resulted in increased cumulated productivity (+16%) as compared to control treatment. Overall, supplemental LED interlighting can represent a feasible technology for tomato greenhouse production also in the Mediterranean region. Full article
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20 pages, 1379 KiB  
Article
Rhizobacteria Isolated from Saline Soil Induce Systemic Tolerance in Wheat (Triticum aestivum L.) against Salinity Stress
by Noshin Ilyas, Roomina Mazhar, Humaira Yasmin, Wajiha Khan, Sumera Iqbal, Hesham El Enshasy and Daniel Joe Dailin
Agronomy 2020, 10(7), 989; https://doi.org/10.3390/agronomy10070989 - 10 Jul 2020
Cited by 48 | Viewed by 4758
Abstract
Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric [...] Read more.
Halo-tolerant plant growth-promoting rhizobacteria (PGPR) have the inherent potential to cope up with salinity. Thus, they can be used as an effective strategy in enhancing the productivity of saline agro-systems. In this study, a total of 50 isolates were screened from the rhizospheric soil of plants growing in the salt range of Pakistan. Out of these, four isolates were selected based on their salinity tolerance and plant growth promotion characters. These isolates (SR1. SR2, SR3, and SR4) were identified as Bacillus sp. (KF719179), Azospirillum brasilense (KJ194586), Azospirillum lipoferum (KJ434039), and Pseudomonas stutzeri (KJ685889) by 16S rDNA gene sequence analysis. In vitro, these strains, in alone and in a consortium, showed better production of compatible solute and phytohormones, including indole acetic acid (IAA), gibberellic acid (GA), cytokinin (CK), and abscisic acid (ABA), in culture conditions under salt stress. When tested for inoculation, the consortium of all four strains showed the best results in terms of improved plant biomass and relative water content. Consortium-inoculated wheat plants showed tolerance by reduced electrolyte leakage and increased production of chlorophyll a, b, and total chlorophyll, and osmolytes, including soluble sugar, proline, amino acids, and antioxidant enzymes (superoxide dismutase, catalase, peroxidase), upon exposure to salinity stress (150 mM NaCl). In conclusion, plant growth-promoting bacteria, isolated from salt-affected regions, have strong potential to mitigate the deleterious effects of salt stress in wheat crop, when inoculated. Therefore, this consortium can be used as potent inoculants for wheat crop under prevailing stress conditions. Full article
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16 pages, 1797 KiB  
Review
Organic Plant Biostimulants and Fruit Quality—A Review
by Mayara Rodrigues, João Leonardo Corte Baptistella, Daniele Caroline Horz, Laura Minatel Bortolato and Paulo Mazzafera
Agronomy 2020, 10(7), 988; https://doi.org/10.3390/agronomy10070988 - 10 Jul 2020
Cited by 40 | Viewed by 9288
Abstract
Plant biostimulants have been increasingly used in agriculture. Plant biostimulants have been mostly investigated regarding their stress attenuation and only a few reports have brought information on their effects on fruit quality, which is related to appearance, chemical and physical attributes. Due to [...] Read more.
Plant biostimulants have been increasingly used in agriculture. Plant biostimulants have been mostly investigated regarding their stress attenuation and only a few reports have brought information on their effects on fruit quality, which is related to appearance, chemical and physical attributes. Due to their organic nature, they have a sustainable appeal, attending the demand of consumers worried about the beneficial effects of healthier foods. This review turns evident the little information available on this matter. As fruits have differentiated metabolism, from pollination to harvest and after-harvesting, it is suggested that further research should focus separately on each stage. Thus, research should aim at quality formation, when the fruits are still attached to the plant, and shelf life extension, after harvesting. Full article
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14 pages, 743 KiB  
Article
The Contribution of Soil Tillage and Nitrogen Rate to the Quality of Maize Grain
by Milena Simić, Vesna Dragičević, Snežana Mladenović Drinić, Jelena Vukadinović, Branka Kresović, Marijenka Tabaković and Milan Brankov
Agronomy 2020, 10(7), 976; https://doi.org/10.3390/agronomy10070976 - 8 Jul 2020
Cited by 23 | Viewed by 2979
Abstract
A soil tillage system adjusted to the soil type and agro-ecological conditions, together with the optimal nutrient supply, is a prerequisite for high maize (Zea mays L.) yield. However, there is little knowledge about the influence of soil tillage and nitrogen (N) [...] Read more.
A soil tillage system adjusted to the soil type and agro-ecological conditions, together with the optimal nutrient supply, is a prerequisite for high maize (Zea mays L.) yield. However, there is little knowledge about the influence of soil tillage and nitrogen (N) rates on maize grain quality. A study was initiated in 1978 in Zemun Polje, Belgrade, Serbia, on the chernozem soil type. The effects of three N rates—0, 180 and 240 kg N ha−1—within three tillage practices—no-tillage, reduced and conventional tillage—and their influence on grain yield (GY) and the content of proteins, starch, oil, total tocopherols and carotenoids, phytic phosphorus (Phy), glutathione (GSH), phenols and inorganic P (Pi) in maize grain were analysed in the period 2016–2018. Differences in maize GY were 2.57 and 3.01 t ha−1 for reduced- or no-tillage, respectively, in comparison to conventional tillage. Conventional tillage and higher N rates contributed to the increase in maize yield and the grain nutritional quality with regard to the increased level of proteins, GSH and Phy. On the other hand reduced inputs were beneficial only for grain quality, in relation to the increase in tocopherols and phenols. Full article
(This article belongs to the Section Innovative Cropping Systems)
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21 pages, 1804 KiB  
Review
Root Involvement in Plant Responses to Adverse Environmental Conditions
by Vicente Vives-Peris, María F. López-Climent, Rosa M. Pérez-Clemente and Aurelio Gómez-Cadenas
Agronomy 2020, 10(7), 942; https://doi.org/10.3390/agronomy10070942 - 1 Jul 2020
Cited by 29 | Viewed by 5416
Abstract
Climate change is altering the environment in which plants grow and survive. An increase in worldwide Earth surface temperatures has been already observed, together with an increase in the intensity of other abiotic stress conditions such as water deficit, high salinity, heavy metal [...] Read more.
Climate change is altering the environment in which plants grow and survive. An increase in worldwide Earth surface temperatures has been already observed, together with an increase in the intensity of other abiotic stress conditions such as water deficit, high salinity, heavy metal intoxication, etc., generating harmful conditions that destabilize agricultural systems. Stress conditions deeply affect physiological, metabolic and morphological traits of plant roots, essential organs for plant survival as they provide physical anchorage to the soil, water and nutrient uptake, mechanisms for stress avoidance, specific signals to the aerial part and to the biome in the soil, etc. However, most of the work performed until now has been mainly focused on aerial organs and tissues. In this review, we summarize the current knowledge about the effects of different abiotic stress conditions on root molecular and physiological responses. First, we revise the methods used to study these responses (omics and phenotyping techniques). Then, we will outline how environmental stress conditions trigger various signals in roots for allowing plant cells to sense and activate the adaptative responses. Later, we discuss on some of the main regulatory mechanisms controlling root adaptation to stress conditions, the interplay between hormonal regulatory pathways and the global changes on gene expression and protein homeostasis. We will present recent advances on how the root system integrates all these signals to generate different physiological responses, including changes in morphology, long distance signaling and root exudation. Finally, we will discuss the new prospects and challenges in this field. Full article
(This article belongs to the Special Issue Sustainable Agriculture Based on Crop Ecophysiological Functioning)
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33 pages, 7194 KiB  
Review
Insights into the Physiological and Biochemical Impacts of Salt Stress on Plant Growth and Development
by Muhammad Adnan Shahid, Ali Sarkhosh, Naeem Khan, Rashad Mukhtar Balal, Shahid Ali, Lorenzo Rossi, Celina Gómez, Neil Mattson, Wajid Nasim and Francisco Garcia-Sanchez
Agronomy 2020, 10(7), 938; https://doi.org/10.3390/agronomy10070938 - 30 Jun 2020
Cited by 191 | Viewed by 23098
Abstract
Climate change is causing soil salinization, resulting in crop losses throughout the world. The ability of plants to tolerate salt stress is determined by multiple biochemical and molecular pathways. Here we discuss physiological, biochemical, and cellular modulations in plants in response to salt [...] Read more.
Climate change is causing soil salinization, resulting in crop losses throughout the world. The ability of plants to tolerate salt stress is determined by multiple biochemical and molecular pathways. Here we discuss physiological, biochemical, and cellular modulations in plants in response to salt stress. Knowledge of these modulations can assist in assessing salt tolerance potential and the mechanisms underlying salinity tolerance in plants. Salinity-induced cellular damage is highly correlated with generation of reactive oxygen species, ionic imbalance, osmotic damage, and reduced relative water content. Accelerated antioxidant activities and osmotic adjustment by the formation of organic and inorganic osmolytes are significant and effective salinity tolerance mechanisms for crop plants. In addition, polyamines improve salt tolerance by regulating various physiological mechanisms, including rhizogenesis, somatic embryogenesis, maintenance of cell pH, and ionic homeostasis. This research project focuses on three strategies to augment salinity tolerance capacity in agricultural crops: salinity-induced alterations in signaling pathways; signaling of phytohormones, ion channels, and biosensors; and expression of ion transporter genes in crop plants (especially in comparison to halophytes). Full article
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66 pages, 1080 KiB  
Review
Two Novel Energy Crops: Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L.—State of Knowledge
by Laura Cumplido-Marin, Anil R. Graves, Paul J. Burgess, Christopher Morhart, Pierluigi Paris, Nicolai D. Jablonowski, Gianni Facciotto, Marek Bury, Reent Martens and Michael Nahm
Agronomy 2020, 10(7), 928; https://doi.org/10.3390/agronomy10070928 - 28 Jun 2020
Cited by 43 | Viewed by 6508
Abstract
Current global temperature increases resulting from human activity threaten many ecosystems and societies, and have led to international and national policy commitments that aim to reduce greenhouse gas emissions. Bioenergy crops provide one means of reducing greenhouse gas emissions from energy production and [...] Read more.
Current global temperature increases resulting from human activity threaten many ecosystems and societies, and have led to international and national policy commitments that aim to reduce greenhouse gas emissions. Bioenergy crops provide one means of reducing greenhouse gas emissions from energy production and two novel crops that could be used for this purpose are Sida hermaphrodita (L.) Rusby and Silphium perfoliatum L. This research examined the existing scientific literature available on both crops through a systematic review. The data were collated according to the agronomy, uses, and environmental benefits of each crop. Possible challenges were associated with high initial planting costs, low yields in low rainfall areas, and for Sida hermaphrodita, vulnerability to Sclerotinia sclerotiorum. However, under appropriate environmental conditions, both crops were found to provide large yields over sustained periods of time with relatively low levels of management and could be used to produce large energy surpluses, either through direct combustion or biogas production. Other potential uses included fodder, fibre, and pharmaceutical uses. Environmental benefits included the potential for phytoremediation, and improvements to soil health, biodiversity, and pollination. The review also demonstrated that environmental benefits, such as pollination, soil health, and water quality benefits could be obtained from the use of Sida hermaphrodita and Silphium perfoliatum relative to existing bioenergy crops such as maize, whilst at the same time reducing the greenhouse gas emissions associated with energy production. Future research should examine the long-term implications of using Sida hermaphrodita and Silphium perfoliatum as well as improve knowledge on how to integrate them successfully within existing farming systems and supply chains. Full article
(This article belongs to the Special Issue Bioenergy Crops: Current Status and Future Prospects)
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15 pages, 3730 KiB  
Article
Positioning Accuracy Comparison of GNSS Receivers Used for Mapping and Guidance of Agricultural Machines
by Pietro Catania, Antonio Comparetti, Pierluigi Febo, Giuseppe Morello, Santo Orlando, Eliseo Roma and Mariangela Vallone
Agronomy 2020, 10(7), 924; https://doi.org/10.3390/agronomy10070924 - 27 Jun 2020
Cited by 49 | Viewed by 5759
Abstract
Global Navigation Satellite Systems (GNSS) allow the determination of the 3D position of a point on the Earth’s surface by measuring the distance from the receiver antenna to the orbital position of at least four satellites. Selecting and buying a GNSS receiver, depending [...] Read more.
Global Navigation Satellite Systems (GNSS) allow the determination of the 3D position of a point on the Earth’s surface by measuring the distance from the receiver antenna to the orbital position of at least four satellites. Selecting and buying a GNSS receiver, depending on farm needs, is the first step for implementing precision agriculture. The aim of this work is to compare the positioning accuracy of four GNSS receivers, different for technical features and working modes: L1/L2 frequency survey-grade Real-Time Kinematic (RTK)-capable Stonex S7-G (S7); L1 frequency RTK-capable Stonex S5 (S5); L1 frequency Thales MobileMapper Pro (TMMP); low-cost L1 frequency Quanum GPS Logger V2 (QLV2). In order to evaluate the positioning accuracy of these receivers, i.e., the distance of the determined points from a reference trajectory, different tests, distinguished by the use or not of Real-Time Kinematic (RTK) differential correction data and/or an external antenna, were carried out. The results show that all satellite receivers tested carried out with the external antenna had an improvement in positioning accuracy. The Thales MobileMapper Pro satellite receiver showed the worst positioning accuracy. The low-cost Quanum GPS Logger V2 receiver surprisingly showed an average positioning error of only 0.550 m. The positioning accuracy of the above-mentioned receiver was slightly worse than that obtained using Stonex S7-G without the external antenna and differential correction (maximum positioning error 0.749 m). However, this accuracy was even better than that recorded using Stonex S5 without differential correction, both with and without the external antenna (average positioning error of 0.962 m and 1.368 m). Full article
(This article belongs to the Special Issue Precision Agriculture for Sustainability)
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15 pages, 1762 KiB  
Article
Biochar Mitigates Combined Effects of Drought and Salinity Stress in Quinoa
by Aizheng Yang, Saqib Saleem Akhtar, Lin Li, Qiang Fu, Quanfeng Li, Muhammad Asif Naeem, Xinyao He, Ze Zhang and Sven-Erik Jacobsen
Agronomy 2020, 10(6), 912; https://doi.org/10.3390/agronomy10060912 - 25 Jun 2020
Cited by 66 | Viewed by 5855
Abstract
Abiotic stresses such as drought and salinity constantly threaten food security. Biochar as a soil amendment has the potential to ameliorate soil and alleviate drought and salinity stress. Multiple studies have been conducted to evaluate the effect of biochar in alleviating independent drought [...] Read more.
Abiotic stresses such as drought and salinity constantly threaten food security. Biochar as a soil amendment has the potential to ameliorate soil and alleviate drought and salinity stress. Multiple studies have been conducted to evaluate the effect of biochar in alleviating independent drought or salinity stress. However, the potential of biochar in mitigating the combined drought and salinity stress on plants has not been studied so far. Therefore, a pot experiment was conducted in the climate-controlled chamber with the objective to investigate the effect of biochar on growth, physiology, and yield of quinoa under independent and combined drought and salinity stress. Quinoa plants were subjected to three irrigation treatments i.e., full irrigation (FI), deficit irrigation (DI), and alternate root-zone drying irrigation (ARD), two saline water treatments (0 and 400 mM) and two levels of biochar (0% and 5% by weight). In the FI treatment, plants were irrigated daily to maintain pot water-holding capacity. In limited irrigation treatments, 70% water of FI was applied either to the whole pot in DI or to one side of the pot alternating in ARD, respectively. The results showed that combined drought and salinity stress drastically affected growth and performance of quinoa compared to the independent drought or salinity stress. However, soil amendment with biochar had positive effect in mitigating both independent and combined effect of drought and salinity on quinoa plants. Furthermore, biochar amendment in ARD under salinity significantly enhanced plant height, shoot biomass, and grain by 11.7%, 18.8%, and 10.2% as compared with DI under salinity, respectively. In addition, leaf photosynthetic rate (An) and stomatal conductance (gs) decreased under limited saline irrigation. Moreover, the interactive effect of biochar and ARD efficiently adjusted the balance between chemical signal (leaf ABA) and hydraulic signal (leaf water potential). Thus, intrinsic water use efficiency (WUEi) and yield in ARD were significantly enhanced compared to DI, especially under salinity stress. Overall, biochar in combination with ARD might be a wise approach for sustaining crop productivity in salt affected and drought stressed areas of the world to ensure food security. Full article
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15 pages, 622 KiB  
Article
Effect of Salinity on Seed Germination and Seedling Development of Sorghum (Sorghum bicolor (L.) Moench) Genotypes
by Ahmad Rajabi Dehnavi, Morteza Zahedi, Agnieszka Ludwiczak, Stefany Cardenas Perez and Agnieszka Piernik
Agronomy 2020, 10(6), 859; https://doi.org/10.3390/agronomy10060859 - 17 Jun 2020
Cited by 147 | Viewed by 14410
Abstract
Salinity is one of the most important abiotic stresses that negatively affects plant growth and development around the world. It has been reported that approximately 19.5% of all irrigated land and 2.1% of dry land is affected by salt stress, and these percentages [...] Read more.
Salinity is one of the most important abiotic stresses that negatively affects plant growth and development around the world. It has been reported that approximately 19.5% of all irrigated land and 2.1% of dry land is affected by salt stress, and these percentages continue to increase. Sorghum, a C4 plant, is the fifth most important cereal in the world. Numerous studies reported that there are high genetic variations in sorghum. These genetic variations can be monitored to search for the most salt-tolerant genotypes. Therefore, the aim of our study was to investigate the responses of ten sorghum genotypes to different levels of salinity. We focused on germination and seedling growth as the most critical stages of plant development. In our research we included germination percentage, germination index, mean germination time, seedling vigor index, seedlings’ shoot and root lengths, fresh and dry seedling weight, and salinity tolerance indices. For data assessment we applied two-way ANOVA, non-metric multidimensional scaling, and hierarchical agglomerative classification. Our results demonstrate that salinity was responsible for 98% of the variation in assessed parameters, whereas genotype effect accounted for only 2% of the documented variation. It can be concluded that seedling traits can be used as a valid criterion for the selection of genotypes with a better tolerance to salinity stress. Full article
(This article belongs to the Special Issue Molecular Responses to Salt Stress in Crop Plants)
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44 pages, 13485 KiB  
Review
Smartphone Applications Targeting Precision Agriculture Practices—A Systematic Review
by Jorge Mendes, Tatiana M. Pinho, Filipe Neves dos Santos, Joaquim J. Sousa, Emanuel Peres, José Boaventura-Cunha, Mário Cunha and Raul Morais
Agronomy 2020, 10(6), 855; https://doi.org/10.3390/agronomy10060855 - 16 Jun 2020
Cited by 68 | Viewed by 20638
Abstract
Traditionally farmers have used their perceptual sensorial systems to diagnose and monitor their crops health and needs. However, humans possess five basic perceptual systems with accuracy levels that can change from human to human which are largely dependent on the stress, experience, health [...] Read more.
Traditionally farmers have used their perceptual sensorial systems to diagnose and monitor their crops health and needs. However, humans possess five basic perceptual systems with accuracy levels that can change from human to human which are largely dependent on the stress, experience, health and age. To overcome this problem, in the last decade, with the help of the emergence of smartphone technology, new agronomic applications were developed to reach better, cost-effective, more accurate and portable diagnosis systems. Conventional smartphones are equipped with several sensors that could be useful to support near real-time usual and advanced farming activities at a very low cost. Therefore, the development of agricultural applications based on smartphone devices has increased exponentially in the last years. However, the great potential offered by smartphone applications is still yet to be fully realized. Thus, this paper presents a literature review and an analysis of the characteristics of several mobile applications for use in smart/precision agriculture available on the market or developed at research level. This will contribute to provide to farmers an overview of the applications type that exist, what features they provide and a comparison between them. Also, this paper is an important resource to help researchers and applications developers to understand the limitations of existing tools and where new contributions can be performed. Full article
(This article belongs to the Section Precision and Digital Agriculture)
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28 pages, 2597 KiB  
Review
Metabolomics: A Tool for Cultivar Phenotyping and Investigation of Grain Crops
by Claude Y. Hamany Djande, Chanel Pretorius, Fidele Tugizimana, Lizelle A. Piater and Ian A. Dubery
Agronomy 2020, 10(6), 831; https://doi.org/10.3390/agronomy10060831 - 11 Jun 2020
Cited by 41 | Viewed by 8190
Abstract
The quality of plants is often enhanced for diverse purposes such as improved resistance to environmental pressures, better taste, and higher yields. Considering the world’s dependence on plants (nutrition, medicine, or biofuel), developing new cultivars with superior characteristics is of great importance. As [...] Read more.
The quality of plants is often enhanced for diverse purposes such as improved resistance to environmental pressures, better taste, and higher yields. Considering the world’s dependence on plants (nutrition, medicine, or biofuel), developing new cultivars with superior characteristics is of great importance. As part of the ‘omics’ approaches, metabolomics has been employed to investigate the large number of metabolites present in plant systems under well-defined environmental conditions. Recent advances in the metabolomics field have greatly expanded our understanding of plant metabolism, largely driven by potential application to agricultural systems. The current review presents the workflow for plant metabolome analyses, current knowledge, and future directions of such research as determinants of cultivar phenotypes. Furthermore, the value of metabolome analyses in contemporary crop science is illustrated. Here, metabolomics has provided valuable information in research on grain crops and identified significant biomarkers under different conditions and/or stressors. Moreover, the value of metabolomics has been redefined from simple biomarker identification to a tool for discovering active drivers involved in biological processes. We illustrate and conclude that the rapid advances in metabolomics are driving an explosion of information that will advance modern breeding approaches for grain crops and address problems associated with crop productivity and sustainable agriculture. Full article
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17 pages, 2664 KiB  
Article
Enhancing Cation Exchange Capacity of Weathered Soils Using Biochar: Feedstock, Pyrolysis Conditions and Addition Rate
by Rimena R. Domingues, Miguel A. Sánchez-Monedero, Kurt A. Spokas, Leônidas C. A. Melo, Paulo F. Trugilho, Murilo Nunes Valenciano and Carlos A. Silva
Agronomy 2020, 10(6), 824; https://doi.org/10.3390/agronomy10060824 - 11 Jun 2020
Cited by 77 | Viewed by 7722
Abstract
The addition of alkaline and high-cation exchange capacity (CEC) biochars is a suitable strategy to increase the CEC of weathered soils. The aim of this study was to evaluate the effect of biochar from different feedstocks and pyrolysis temperatures on the CEC of [...] Read more.
The addition of alkaline and high-cation exchange capacity (CEC) biochars is a suitable strategy to increase the CEC of weathered soils. The aim of this study was to evaluate the effect of biochar from different feedstocks and pyrolysis temperatures on the CEC of two contrasting Oxisols. Biochars produced from chicken manure (CM), eucalyptus sawdust (ES), coffee husk (CH) and sugarcane bagasse (SB),plus a control (without biochar), at 350, 450, and 750 °C were mixed with the soils at 2; 5; 10 and 20% (w/w) and incubated for 9 months. Feedstock, pyrolysis temperature and addition rate of biochar were key factors controlling the alteration of soil CEC. The CH biochar pyrolyzed at 350 °C was the most effective matrix at increasing soil CEC. In a rate-dependent way, ES and SB biochars increased C contents of both soils without improving soil CEC. The efficiency of high-ash biochars in enhancing soil CEC in both Oxisols was limited by the alkalization caused by high rates of CH and CM biochars. The increase in CEC is soil-dependent and modulated by high-ash biochar CEC and application rate, as well as by the original soil CEC. Full article
(This article belongs to the Special Issue Interaction of Biochar on Organic Waste Composting)
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22 pages, 1896 KiB  
Review
Arbuscular Mycorrhizal Fungi as Potential Agents in Ameliorating Heavy Metal Stress in Plants
by Rajni Dhalaria, Dinesh Kumar, Harsh Kumar, Eugenie Nepovimova, Kamil Kuča, Muhammad Torequl Islam and Rachna Verma
Agronomy 2020, 10(6), 815; https://doi.org/10.3390/agronomy10060815 - 9 Jun 2020
Cited by 112 | Viewed by 9713
Abstract
Heavy metal accumulation in plants is a severe environmental problem, rising at an expeditious rate. Heavy metals such as cadmium, arsenic, mercury and lead are known environmental pollutants that exert noxious effects on the morpho-physiological and biological attributes of a plant. Due to [...] Read more.
Heavy metal accumulation in plants is a severe environmental problem, rising at an expeditious rate. Heavy metals such as cadmium, arsenic, mercury and lead are known environmental pollutants that exert noxious effects on the morpho-physiological and biological attributes of a plant. Due to their mobile nature, they have become an extended part of the food chain and affect human health. Arbuscular mycorrhizal fungi ameliorate metal toxicity as they intensify the plant’s ability to tolerate metal stress. Mycorrhizal fungi have vesicles, which are analogous to fungal vacuoles and accumulate massive amount of heavy metals in them. With the help of a pervasive hyphal network, arbuscular mycorrhizal fungi help in the uptake of water and nutrients, thereby abating the use of chemical fertilizers on the plants. They also promote resistance parameters in the plants, secrete a glycoprotein named glomalin that reduces the metal uptake in plants by forming glycoprotein–metal complexes, and improve the quality of the soil. They also assist plants in phytoremediation by increasing the absorptive area, increase the antioxidant response, chelate heavy metals and stimulate genes for protein synthesis that reduce the damage caused by free radicals. The current manuscript focuses on the uptake of heavy metals, accumulation, and arbuscular mycorrhizal impact in ameliorating heavy metal stress in plants. Full article
(This article belongs to the Special Issue Remediation of Contaminated Soil for Food Security)
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16 pages, 1013 KiB  
Article
The Use of Proline in Screening for Tolerance to Drought and Salinity in Common Bean (Phaseolus vulgaris L.) Genotypes
by Sugenith Arteaga, Lourdes Yabor, María José Díez, Jaime Prohens, Monica Boscaiu and Oscar Vicente
Agronomy 2020, 10(6), 817; https://doi.org/10.3390/agronomy10060817 - 9 Jun 2020
Cited by 66 | Viewed by 4507
Abstract
The selection of stress-resistant cultivars, to be used in breeding programmes aimed at enhancing the drought and salt tolerance of our major crops, is an urgent need for agriculture in a climate change scenario. In the present study, the responses to water deficit [...] Read more.
The selection of stress-resistant cultivars, to be used in breeding programmes aimed at enhancing the drought and salt tolerance of our major crops, is an urgent need for agriculture in a climate change scenario. In the present study, the responses to water deficit and salt stress treatments, regarding growth inhibition and leaf proline (Pro) contents, were analysed in 47 Phaseolus vulgaris genotypes of different origins. A two-way analysis of variance (ANOVA), Pearson moment correlations and principal component analyses (PCAs) were performed on all measured traits, to assess the general responses to stress of the investigated genotypes. For most analysed growth variables and Pro, the effects of cultivar, treatment and their interactions were highly significant (p < 0.001); the root morphological traits, stem diameter and the number of leaves were mostly due to uncontrolled variation, whereas the variation of fresh weight and water content of stems and leaves was clearly induced by stress. Under our experimental conditions, the average effects of salt stress on plant growth were relatively weaker than those of water deficit. In both cases, however, growth inhibition was mostly reflected in the stress-induced reduction of fresh weight and water contents of stems and leaves. Pro, on the other hand, was the only variable showing a negative correlation with all growth parameters, but particularly with those of stems and leaves mentioned above, as indicated by the Pearson correlation coefficients and the loading plots of the PCAs. Therefore, in common beans, higher stress-induced accumulation of Pro is unequivocally associated with a stronger inhibition of growth; that is, with a higher sensitivity to stress of the corresponding cultivar. We propose the use of Pro as a suitable biochemical marker for simple, rapid, large-scale screenings of bean genotypes, to exclude the most sensitive, those accumulating higher Pro concentrations in response to water or salt stress treatments. Full article
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25 pages, 1790 KiB  
Review
Facing Climate Change: Application of Microbial Biostimulants to Mitigate Stress in Horticultural Crops
by Daniela Sangiorgio, Antonio Cellini, Irene Donati, Chiara Pastore, Claudia Onofrietti and Francesco Spinelli
Agronomy 2020, 10(6), 794; https://doi.org/10.3390/agronomy10060794 - 3 Jun 2020
Cited by 77 | Viewed by 9481
Abstract
In the current scenario of rapidly evolving climate change, crop plants are more frequently subjected to stresses of both abiotic and biotic origin, including exposure to unpredictable and extreme climatic events, changes in plant physiology, growing season and phytosanitary hazard, and increased losses [...] Read more.
In the current scenario of rapidly evolving climate change, crop plants are more frequently subjected to stresses of both abiotic and biotic origin, including exposure to unpredictable and extreme climatic events, changes in plant physiology, growing season and phytosanitary hazard, and increased losses up to 30% and 50% in global agricultural productions. Plants coevolved with microbial symbionts, which are involved in major functions both at the ecosystem and plant level. The use of microbial biostimulants, by exploiting this symbiotic interaction, represents a sustainable strategy to increase plant performances and productivity, even under stresses due to climate changes. Microbial biostimulants include beneficial fungi, yeasts and eubacteria sharing the ability to improve plant nutrition, growth, productivity and stress tolerance. This work reports the current knowledge on microbial biostimulants and provides a critical review on their possible use to mitigate the biotic and abiotic stresses caused by climate changes. Currently, available products often provide a general amelioration of cultural conditions, but their action mechanisms are largely undetermined and their effects often unreliable. Future research may lead to more specifically targeted products, based on the characterization of plant-microbe and microbial community interactions. Full article
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21 pages, 8779 KiB  
Article
Phytotoxic Effects of Three Natural Compounds: Pelargonic Acid, Carvacrol, and Cinnamic Aldehyde, against Problematic Weeds in Mediterranean Crops
by Marta Muñoz, Natalia Torres-Pagán, Rosa Peiró, Rubén Guijarro, Adela M. Sánchez-Moreiras and Mercedes Verdeguer
Agronomy 2020, 10(6), 791; https://doi.org/10.3390/agronomy10060791 - 2 Jun 2020
Cited by 33 | Viewed by 5802
Abstract
Weeds and herbicides are important stress factors for crops. Weeds are responsible for great losses in crop yields, more than 50% in some crops if left uncontrolled. Herbicides have been used as the main method for weed control since their development after the [...] Read more.
Weeds and herbicides are important stress factors for crops. Weeds are responsible for great losses in crop yields, more than 50% in some crops if left uncontrolled. Herbicides have been used as the main method for weed control since their development after the Second World War. It is necessary to find alternatives to synthetic herbicides that can be incorporated in an Integrated Weed Management Program, to produce crops subjected to less stress in a more sustainable way. In this work, three natural products: pelargonic acid (PA), carvacrol (CV), and cinnamic aldehyde (CA) were evaluated, under greenhouse conditions in postemergence assays, against problematic weeds in Mediterranean crops Amaranthus retroflexus, Avena fatua, Portulaca oleracea, and Erigeron bonariensis, to determine their phytotoxic potential. The three products showed a potent herbicidal activity, reaching high efficacy (plant death) and damage level in all species, being PA the most effective at all doses applied, followed by CA and CV. These products could be good candidates for bioherbicides formulations. Full article
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21 pages, 1846 KiB  
Article
Effects of ZnO Nanoparticles and Biochar of Rice Straw and Cow Manure on Characteristics of Contaminated Soil and Sunflower Productivity, Oil Quality, and Heavy Metals Uptake
by Mahmoud F. Seleiman, Majed A. Alotaibi, Bushra Ahmed Alhammad, Basmah M. Alharbi, Yahya Refay and Shimaa A. Badawy
Agronomy 2020, 10(6), 790; https://doi.org/10.3390/agronomy10060790 - 2 Jun 2020
Cited by 78 | Viewed by 5629
Abstract
Contaminated soils can cause a potential risk into the health of the environment and soil as well as the quality and productivity of plants. The objectives of our study were to investigate the integrative advantageous effects of foliar ZnO nanoparticles (NPs) (60 mg [...] Read more.
Contaminated soils can cause a potential risk into the health of the environment and soil as well as the quality and productivity of plants. The objectives of our study were to investigate the integrative advantageous effects of foliar ZnO nanoparticles (NPs) (60 mg Zn NPs L−1), rice straw biochar (RSB; 8.0 t ha−1), cow-manure biochar (CMB, 8.0 t ha−1), and a combination thereof (50% of each) on sunflowers grown in agricultural land irrigated with polluted wastewater for the long term (≈50 years). The availability of heavy metals (HMs) in soil, HMs accumulation in whole biomass aboveground, growth, productivity, and quality characteristics of the sunflower were investigated. The combination treatment significantly minimized the availability of HMs in soil, and, consequently, substantially lessened the uptake of HMs by the sunflower, compared to treatments of ZnO NPs and control (i.e., untreated soil). The application of the combination treatment reduced the availability of Pb, Cr, Cu, and Cd in the soil by 78.6%, 115.3%, 153.3%, and 178.5% in comparison to untreated plots post-harvest, respectively. Compared to untreated plots, it also reduced the Pb, Cr, Cu, and Cd in plant biomass by 1.13, 5.19, 3.88, and 0.26 mg kg−1 DM, respectively. Furthermore, combination treatment followed by biochar as an individual application caused a significant improvement in sunflower productivity and quality in comparison to untreated soil. For instance, seed yield ha−1, 100-seed weight, and number of seeds per head obtained from the combination treatment was greater than the results obtained from the untreated plots by 42.6%, 47.0%, and 50.4%, respectively. In summary, the combined treatment of NPs and both RSB and CMB is recommended as a result of their positive influence on sunflower oil quality and yield as well as on minimizing the negative influences of HMs. Full article
(This article belongs to the Special Issue Impact of Biochar and Compost on Soil Quality and Crop Yield)
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23 pages, 824 KiB  
Review
The Role of Stress-Responsive Transcription Factors in Modulating Abiotic Stress Tolerance in Plants
by Youngdae Yoon, Deok Hyun Seo, Hoyoon Shin, Hui Jin Kim, Chul Min Kim and Geupil Jang
Agronomy 2020, 10(6), 788; https://doi.org/10.3390/agronomy10060788 - 1 Jun 2020
Cited by 117 | Viewed by 8501
Abstract
Abiotic stresses, such as drought, high temperature, and salinity, affect plant growth and productivity. Furthermore, global climate change may increase the frequency and severity of abiotic stresses, suggesting that development of varieties with improved stress tolerance is critical for future sustainable crop production. [...] Read more.
Abiotic stresses, such as drought, high temperature, and salinity, affect plant growth and productivity. Furthermore, global climate change may increase the frequency and severity of abiotic stresses, suggesting that development of varieties with improved stress tolerance is critical for future sustainable crop production. Improving stress tolerance requires a detailed understanding of the hormone signaling and transcriptional pathways involved in stress responses. Abscisic acid (ABA) and jasmonic acid (JA) are key stress-response hormones in plants, and some stress-responsive transcription factors such as ABFs and MYCs function as direct components of ABA and JA signaling, playing a pivotal role in plant tolerance to abiotic stress. In addition, extensive studies have identified other stress-responsive transcription factors belonging to the NAC, AP2/ERF, MYB, and WRKY families that mediate plant response and tolerance to abiotic stress. These suggest that transcriptional regulation of stress-responsive genes is an essential step to determine the mechanisms underlying plant stress responses and tolerance to abiotic stress, and that these transcription factors may be important targets for development of crops with enhanced abiotic stress tolerance. In this review, we briefly describe the mechanisms underlying plant abiotic stress responses, focusing on ABA and JA metabolism and signaling pathways. We then summarize the diverse array of transcription factors involved in plant responses to abiotic stress, while noting their potential applications for improvement of stress tolerance. Full article
(This article belongs to the Special Issue The Role of Growth Regulators in Crop under Abiotic Stress)
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18 pages, 2246 KiB  
Article
Morphometric Characteristics, Polyphenols and Ascorbic Acid Variation in Brassica oleracea L. Novel Foods: Sprouts, Microgreens and Baby Leaves
by Maria Concetta Di Bella, Agnieszka Niklas, Stefania Toscano, Valentina Picchi, Daniela Romano, Roberto Lo Scalzo and Ferdinando Branca
Agronomy 2020, 10(6), 782; https://doi.org/10.3390/agronomy10060782 - 31 May 2020
Cited by 38 | Viewed by 4835
Abstract
In the present study, we investigated the content and profile of polyphenols (PPH), ascorbic acid (AA), the Folin–Ciocalteu index (FCI), and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radical (ROO)) variation during three different plant growth stages (sprouts, microgreens and baby leaves) of two [...] Read more.
In the present study, we investigated the content and profile of polyphenols (PPH), ascorbic acid (AA), the Folin–Ciocalteu index (FCI), and antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) and peroxyl radical (ROO)) variation during three different plant growth stages (sprouts, microgreens and baby leaves) of two broccoli types, the traditional Sicilian sprouting broccoli landrace (‘Broccolo Nero’) and the broccoli standard (‘Cavolo broccolo Ramoso Calabrese’), and the standard commercial cultivar of kale (‘Cavolo Lacinato Nero di Toscana’). All biomasses collected were freeze-dried for PPH, AA, FCI, DPPH and ROO analysis. The highest polyphenol content was observed for ‘Broccolo Nero’ (BN) and ‘Cavolo Broccolo Ramoso Calabrese’ (CR), and generally sprouts showed significantly higher values compared to the microgreens and the baby leaves. The AA, FCI, DDPH and ROO significantly vary with regards to the cultivar and the plant growth stage, showing interaction between the two experimental factors analyzed. The interaction detected showed higher values for the antioxidant traits of the proposed novel food, especially for the two broccoli cultivars in the sprout growth stage in comparison to the microgreens and baby leaves. Our results suggest that the antioxidant activity is partially dependent on kaempferol and apigenin. The PPH compounds showed the highest values of kaempferol and apigenin for ‘Broccolo nero’, whereas for the other two cultivars studied, only kaempferol was the main compound represented. The data acquired are of interest for increasing the healthy traits of the novel food proposed showing the contribution offered by the neglected LRs until now underutilized and at risk of extinction. The germplasm conserved in several world genebanks could support and diversify the organic vegetable items, providing us with added-value products for organic food supply chains. Full article
(This article belongs to the Special Issue Sprouts, Microgreens and Edible Flowers as Novel Functional Foods)
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22 pages, 2544 KiB  
Article
PGPR Modulation of Secondary Metabolites in Tomato Infested with Spodoptera litura
by Bani Kousar, Asghari Bano and Naeem Khan
Agronomy 2020, 10(6), 778; https://doi.org/10.3390/agronomy10060778 - 30 May 2020
Cited by 42 | Viewed by 5632
Abstract
The preceding climate change demonstrates overwintering of pathogens that lead to increased incidence of insects and pest attack. Integration of ecological and physiological/molecular approaches are imperative to encounter pathogen attack in order to enhance crop yield. The present study aimed to evaluate the [...] Read more.
The preceding climate change demonstrates overwintering of pathogens that lead to increased incidence of insects and pest attack. Integration of ecological and physiological/molecular approaches are imperative to encounter pathogen attack in order to enhance crop yield. The present study aimed to evaluate the effects of two plant growth promoting rhizobacteria (Bacillus endophyticus and Pseudomonas aeruginosa) on the plant physiology and production of the secondary metabolites in tomato plants infested with Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae). The surface sterilized seeds of tomato were inoculated with plant growth promoting rhizobacteria (PGPR) for 3–4 h prior to sowing. Tomato leaves at 6 to 7 branching stage were infested with S. litura at the larval stage of 2nd instar. Identification of secondary metabolites and phytohormones were made from tomato leaves using thin-layer chromatography (TLC) and high performance liquid chromatography (HPLC) and fourier-transform infrared spectroscopy (FTIR). Infestation with S. litura significantly decreased plant growth and yield. The PGPR inoculations alleviated the adverse effects of insect infestation on plant growth and fruit yield. An increased level of protein, proline and sugar contents and enhanced activity of superoxide dismutase (SOD) was noticed in infected tomato plants associated with PGPR. Moreover, p-kaempferol, rutin, caffeic acid, p-coumaric acid and flavonoid glycoside were also detected in PGPR inoculated infested plants. The FTIR spectra of the infected leaf samples pre-treated with PGPR revealed the presence of aldehyde. Additionally, significant amounts of indole-3-acetic acid (IAA), salicylic acid (SA) and abscisic acid (ABA) were detected in the leaf samples. From the present results, we conclude that PGPR can promote growth and yield of tomatoes under attack and help the host plant to combat infestation via modulation in IAA, SA, ABA and other secondary metabolites. Full article
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19 pages, 1634 KiB  
Article
Soil Loss Estimation for Conservation Planning in the Welmel Watershed of the Genale Dawa Basin, Ethiopia
by Yared Mesfin Tessema, Justyna Jasińska, Lemma Tiki Yadeta, Marcin Świtoniak, Radosław Puchałka and Eyob Gebrehiwot Gebregeorgis
Agronomy 2020, 10(6), 777; https://doi.org/10.3390/agronomy10060777 - 30 May 2020
Cited by 46 | Viewed by 4601
Abstract
As a form of environmental degradation, soil degradation directly or indirectly affects many lives through decreased agricultural yields, increased flooding and habitat loss. Soil loss has been increasing in most parts of the world and is most pronounced in tropical developing countries where [...] Read more.
As a form of environmental degradation, soil degradation directly or indirectly affects many lives through decreased agricultural yields, increased flooding and habitat loss. Soil loss has been increasing in most parts of the world and is most pronounced in tropical developing countries where there is poor or zero soil and water conservation (SWC) planning and management activities. Identifying areas prone to soil erosion has also been inadequate, having not been informed by dedicated scientific studies. This is true of the poorly understood watershed of Welmel in the Oromia region of Ethiopia, where most livelihoods heavily rely upon agriculture. To plan effective SWC management techniques, a solid knowledge of spatial variations across different climate, land use and soil erosion is essential. This study has aimed at identifying potential areas needing SWC practices through conducting a spatial modeling of soil erosion within the Welmel watershed’s Genale Dawa basin using a geographic information system (GIS), remote sensing (RS), multiple factors as land uses and climate. The Welmel catchment is located in southeastern Ethiopia and extends between 5°0′0″ N–7°45′00″ N and 39°0′0″ E–41°15′0″ E. The revised universal soil loss equation (RUSLE), which was previously adapted to Ethiopian conditions, was used to estimate potential soil loss. It used information on interpolated rainfall erosivity (R), soil erodibility (K), vegetation cover (C) and topography (LS) from a digital elevation model (DEM) and that of conservation practices (P) from satellite images. The study demonstrates that the RUSLE using GIS and RS considering different climates and land management practices provides a great advantage in that it allows one to spatially analyze multilayer data in order to identify soil erosion-prone areas and thereby develop the most appropriate watershed management strategy. The mean soil loss was determined to be 31 tons ha−1 year−1 and it varied between 0 and 169 tons ha−1 year−1. About 79% of the watershed lies within the tolerable level of 11 tons ha−1 year−1. However, the remaining 21% has a high soil truncation trait, mainly due to its steeper slope and use as cultivated land. Our study identifies cultivated and deforested areas of the watershed as the potential SWC practice demanding areas. Thus, the application of RUSEL using GIS across different land management practices and climate zones is a potential tool for identifying SWC demanding sites. This remains helpful in efforts towards sustainable land management practices for the sustainable livelihood of the local human population. Full article
(This article belongs to the Section Soil and Plant Nutrition)
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13 pages, 255 KiB  
Article
Tillage, Crop Rotation and Crop Residue Management Effects on Nutrient Availability in a Sweet Sorghum-Based Cropping System in Marginal Soils of South Africa
by Mashapa E. Malobane, Adornis D. Nciizah, Fhatuwani N. Mudau and Isaiah I.C Wakindiki
Agronomy 2020, 10(6), 776; https://doi.org/10.3390/agronomy10060776 - 30 May 2020
Cited by 36 | Viewed by 4722
Abstract
The low soil fertility status of South African marginal soils threatens sustainable production of biofuel feedstock in smallholder farmers. It is therefore imperative to development sustainable and optimal management practices that improve soil fertility. The objective of this study was to determine the [...] Read more.
The low soil fertility status of South African marginal soils threatens sustainable production of biofuel feedstock in smallholder farmers. It is therefore imperative to development sustainable and optimal management practices that improve soil fertility. The objective of this study was to determine the effect of tillage, rotation and crop residue management on nutrient availability in a bioenergy sweet sorghum-based cropping system in marginal soils. Two tillage levels, no-till (NT) and conventional tillage (CT); two crop rotations, sweet sorghum–grazing vetch–sweet sorghum (SVS) and sweet sorghum–fallow–sweet sorghum (SFS); and three crop residue retention levels, 0%, 15% and 30%, were tested. No-till enhanced total nitrogen, total organic nitrogen (TON), magnesium (Mg) and sodium (Na) by 3.19% to 45% compared to CT. SVS rotation increased ammonium (NH4+-N) and nitrate (NO3-N) by 3.42% to 5.98% compared to SFS. A 30% crop residue retention increased NH4+-N, NO3-N, available phosphorus (Available P), cation exchange capacity (CEC), calcium (Ca), Mg and potassium (K) by 3.58% to 31.94% compared to crop residue removal. In the short term, a 30% crop residue retention was the main treatment that enhanced soil fertility. The application of NT−30% was a better practice to enhance soil fertility. However, research on inclusion of crop diversity/intercropping can add more value to the NT–30% practice in enhancing soil fertility. Full article
(This article belongs to the Special Issue Effects of Agricultural Management on Soil Properties and Health)
17 pages, 456 KiB  
Article
Effects of Genotype, Growing Season and Nitrogen Level on Gluten Protein Assembly of Durum Wheat Grown under Mediterranean Conditions
by Anna Gagliardi, Federica Carucci, Stefania Masci, Zina Flagella, Giuseppe Gatta and Marcella Michela Giuliani
Agronomy 2020, 10(5), 755; https://doi.org/10.3390/agronomy10050755 - 25 May 2020
Cited by 31 | Viewed by 3259
Abstract
Water deficit and high temperatures are the main environmental factors which affect both wheat yield and technological quality in the Mediterranean climate. The aim of the study was to evaluate the variation in the gluten protein assembly of four durum wheat genotypes in [...] Read more.
Water deficit and high temperatures are the main environmental factors which affect both wheat yield and technological quality in the Mediterranean climate. The aim of the study was to evaluate the variation in the gluten protein assembly of four durum wheat genotypes in relation to growing seasons and different nitrogen levels. The genotypes, Marco Aurelio, Quadrato, Pietrafitta and Redidenari, were grown under three nitrogen levels (36, 90 and 120 kg ha−1) during two growing seasons in Southern Italy. Significant lower yield and a higher protein concentration were observed in the year characterized by a higher temperature at the end of the crop cycle. The effect of the high temperatures on protein assembly was different for the genotypes in relation to their earliness. Based on PCA, in the warmer year, only the medium-early genotype Quadrato showed positive values along the “protein polymerization degree” factor, while the medium and medium-late genotypes, Marco Aurelio and Pietrafitta showed negative values along the “proteins assembly” factor. No clear separation along the two factors was observed for the early genotype Redidenari. The variation in gluten protein assembly observed in the four genotypes in relation to the growing season might help breeding programs to select genotypes suitable for facing the ongoing climate changes in Mediterranean area. Full article
(This article belongs to the Special Issue Durum Wheat Breeding and Genetics)
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26 pages, 4953 KiB  
Article
Smart Farming Technology Trends: Economic and Environmental Effects, Labor Impact, and Adoption Readiness
by Athanasios T. Balafoutis, Frits K. Van Evert and Spyros Fountas
Agronomy 2020, 10(5), 743; https://doi.org/10.3390/agronomy10050743 - 21 May 2020
Cited by 66 | Viewed by 15070
Abstract
Farming faces challenges that increase the adverse effects on farms’ economics, labor, and the environment. Smart farming technologies (SFTs) are expected to assist in reverting this situation. In this work, 1064 SFTs were derived from scientific papers, research projects, and industrial products. They [...] Read more.
Farming faces challenges that increase the adverse effects on farms’ economics, labor, and the environment. Smart farming technologies (SFTs) are expected to assist in reverting this situation. In this work, 1064 SFTs were derived from scientific papers, research projects, and industrial products. They were classified by technology readiness level (TRL), typology, and field operation, and they were assessed for their economic, environmental, and labor impact, as well as their adoption readiness from end-users. It was shown that scientific articles dealt with SFTs of lower TRL than research projects. In scientific articles, researchers investigated mostly recording technologies, while, in research projects, they focused primarily on farm management information systems and robotic/automation systems. Scouting technologies were the main SFT type in scientific papers and research projects, but variable rate application technologies were mostly located in commercial products. In scientific papers, there was limited analysis of economic, environmental, and labor impact of the SFTs under investigation, while, in research projects, these impacts were studied thoroughly. Further, in commercial SFTs, the focus was on economic impact and less on labor and environmental issues. With respect to adoption readiness, it was found that all of the factors to facilitate SFT adoption became more positive moving from SFTs in scientific papers to fully functional commercial SFTs, indicating that SFTs reach the market when most of these factors are addressed for the benefit of the farmers. This SFT analysis is expected to inform researchers on adapting their research, as well as help policy-makers adjust their strategy toward digitized agriculture adoption and farmers with the current situation and future trends of SFTs. Full article
(This article belongs to the Special Issue Precision Agriculture)
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28 pages, 355 KiB  
Article
Profiling of Essential Oils Components and Polyphenols for Their Antioxidant Activity of Medicinal and Aromatic Plants Grown in Different Environmental Conditions
by Antonios Chrysargyris, Maria Mikallou, Spyridon Petropoulos and Nikolaos Tzortzakis
Agronomy 2020, 10(5), 727; https://doi.org/10.3390/agronomy10050727 - 19 May 2020
Cited by 52 | Viewed by 5578
Abstract
In the present study, the yield, the chemical composition, and the antioxidant activities of the essential oils (EOs) of eight medicinal and aromatic plants (MAPs) cultivated under two environmental conditions characterized by a different altitude (namely mountainous and plain) were evaluated. Cultivation at [...] Read more.
In the present study, the yield, the chemical composition, and the antioxidant activities of the essential oils (EOs) of eight medicinal and aromatic plants (MAPs) cultivated under two environmental conditions characterized by a different altitude (namely mountainous and plain) were evaluated. Cultivation at different environmental conditions resulted in significant differences in the chemical composition and antioxidant activity for most of the studied species. In particular, high altitudes resulted in increased phenolic compounds’ content and antioxidant activity for artemisia plants, while specific parameters increased in the case of spearmint (total phenols) and rosemary (flavonoids). In contrast, in pelargonium, all the tested parameters were positively affected in the plain area, whereas, for laurel and sage, only flavanols remained unaffected. EO yield in mountainous pelargonium and spearmint decreased while, in mountainous laurel, pelargonium and spearmint increased when compared to plain areas. In addition, the major EO constituents’ content for most of the species were affected by environmental conditions. The 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and ferric reducing antioxidant power (FRAP) were variably correlated with total phenols, flavonoids, and flavanols, depending on the species and the altitude. Lastly, in limited cases, antioxidant activity (DPPH or FRAP values) was positively correlated with some EO components (e.g., borneol and β-pinene in artemisia and laurel plants grown in the plain, respectively, or 1,8-cineole in mountainous grown verbena plants). In conclusion, environmental conditions (altitude) affected antioxidants’ content and EO yield and composition of the studied MAPs. These findings can be used to introduce cultivation of MAPs in specific ecosystems for the production of high added value products. Full article
19 pages, 2517 KiB  
Article
Minimizing Adverse Effects of Pb on Maize Plants by Combined Treatment with Jasmonic, Salicylic Acids and Proline
by Mahmoud R. Sofy, Mahmoud F. Seleiman, Bushra A. Alhammad, Basmah M. Alharbi and Heba I. Mohamed
Agronomy 2020, 10(5), 699; https://doi.org/10.3390/agronomy10050699 - 14 May 2020
Cited by 112 | Viewed by 5013
Abstract
Lead (Pb) is a toxic heavy metal (HM) that harms plant growth and productivity. Phytohormones, such as jasmonic acid (JA) and salicylic acid (SA), and osmoprotectants, such as proline (Pro), play an important role in the physiological and biochemical processes of plants. We [...] Read more.
Lead (Pb) is a toxic heavy metal (HM) that harms plant growth and productivity. Phytohormones, such as jasmonic acid (JA) and salicylic acid (SA), and osmoprotectants, such as proline (Pro), play an important role in the physiological and biochemical processes of plants. We investigated the effect of exogenous applications of JA, SA, Pro, and their combination on Pb-stress tolerance in maize as well as their effect on physiological, biochemical, and yield traits. Pb exposure severely affected maize plants, reducing growth, yield, photosynthetic pigments, and mineral (nitrogen, phosphorus, and potassium) nutrients, as well as enhancing electrolyte leakage (EL), malondialdehyde (MDA) accumulation, osmolytes, and non-enzymatic and enzymatic antioxidants. The application of JA, SA, Pro, and their combination enhanced plant growth and induced pigment biosynthesis, and decreased EL, MDA accumulation, and Pb concentration. All treatments enhanced Pro and total soluble sugar production, glutathione activity, ascorbic acid, phenol, superoxide dismutase, catalase, peroxidase, and mineral nutrients. JA, SA, and Pro application improved physiological processes directly or indirectly, thereby enhancing the ability of maize plants to overcome oxidative damage caused by Pb toxicity. The combination of JA, SA, and Pro was the most efficient treatment for maize plant growth and development, eliminating the negative consequences of Pb stress. Full article
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18 pages, 841 KiB  
Article
Effects of Root Temperature on the Plant Growth and Food Quality of Chinese Broccoli (Brassica oleracea var. alboglabra Bailey)
by Fang He, Björn Thiele, Sharin Santhiraraja-Abresch, Michelle Watt, Thorsten Kraska, Andreas Ulbrich and Arnd J. Kuhn
Agronomy 2020, 10(5), 702; https://doi.org/10.3390/agronomy10050702 - 14 May 2020
Cited by 18 | Viewed by 4969
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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15 pages, 727 KiB  
Article
Rootstock and Arbuscular Mycorrhiza Combinatorial Effects on Eggplant Crop Performance and Fruit Quality under Greenhouse Conditions
by Leo Sabatino, Giovanni Iapichino, Beppe Benedetto Consentino, Fabio D’Anna and Youssef Rouphael
Agronomy 2020, 10(5), 693; https://doi.org/10.3390/agronomy10050693 - 13 May 2020
Cited by 34 | Viewed by 3501
Abstract
The herbaceous grafting of fruiting vegetables is considered a toolbox for safeguarding yield stability under various distresses and for improving fruit quality. Inoculation with arbuscular mycorrhiza (AM) fungi seems also to be an efficient tool for increasing the assimilation, uptake and translocation of [...] Read more.
The herbaceous grafting of fruiting vegetables is considered a toolbox for safeguarding yield stability under various distresses and for improving fruit quality. Inoculation with arbuscular mycorrhiza (AM) fungi seems also to be an efficient tool for increasing the assimilation, uptake and translocation of macroelements and microelements, for modulating plant secondary metabolism and for overcoming several forms of plant distress. The present work evaluated the combined effect of grafting the “Birgah” (B) eggplant onto its wild/allied relatives’ rootstocks (Solanum torvum (T), S. macrocarpon (M) and S. paniculatum (P)) and AM fungi (R. irregularis) on the yield, fruit quality, nitrogen use efficiency, mineral profile, and nutritional and functional quality. The B/T, B/M and B/P grafting combinations significantly increased the marketable fruit and fruit number compared with those in the ungrafted control. Furthermore, irrespective of the grafting combinations, AM fungi significantly enhanced the marketable fruit, fruit number and nitrogen use efficiency (NUE) by 13.3%, 12.7% and 13.3%, respectively compared to those in the untreated control. Exposing the B/T and B/P grafted plants to the +AM treatment significantly increased the ascorbic acid contents by 17.2% and 10.4%, respectively, compared with those in the ungrafted control. Fruits from the combination B/P × +AM had a higher chlorogenic acid content than fruits from the ungrafted control plots. Finally, the B/T × +AM and B/P × +AM combinations decreased glycoalkaloids by 58.7% and 63.7%, respectively, compared with those in the ungrafted control, which represents a highly important target for eggplant fruit healthiness. Full article
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14 pages, 1977 KiB  
Article
Production of Cellulose Nanofibers from Olive Tree Harvest—A Residue with Wide Applications
by Mónica Sánchez-Gutiérrez, Eduardo Espinosa, Isabel Bascón-Villegas, Fernando Pérez-Rodríguez, Elena Carrasco and Alejandro Rodríguez
Agronomy 2020, 10(5), 696; https://doi.org/10.3390/agronomy10050696 - 13 May 2020
Cited by 51 | Viewed by 5836
Abstract
With the aim of identifying new sources to produce cellulose nanofibers, olive tree pruning biomass (OTPB) was proposed for valorization as a sustainable source of cellulose. OTPB was subjected to a soda pulping process for cellulose purification and to facilitate the delamination of [...] Read more.
With the aim of identifying new sources to produce cellulose nanofibers, olive tree pruning biomass (OTPB) was proposed for valorization as a sustainable source of cellulose. OTPB was subjected to a soda pulping process for cellulose purification and to facilitate the delamination of the fiber in the nanofibrillation process. Unbleached and bleached pulp were used to study the effect of lignin in the production of cellulose nanofibers through different pretreatments (mechanical and TEMPO-mediated oxidation). High-pressure homogenization was used as the nanofibrillation treatment. It was observed that for mechanical pretreatment, the presence of lignin in the fiber produces a greater fibrillation, resulting in a smaller width than that achieved with bleached fiber. In the case of TEMPO-mediated oxidation, the cellulose nanofiber characteristics show that the presence of lignin has an adverse effect on fiber oxidation, resulting in lower nanofibrillation. It was observed that the crystallinity of the nanofibers is lower than that of the original fiber, especially for unbleached nanofibers. The residual lignin content resulted in a greater thermal stability of the cellulose nanofibers, especially for those obtained by TEMPO-mediated oxidation. The characteristics of the cellulose nanofibers obtained in this work identify a gateway to many possibilities for reinforcement agents in paper suspension and polymeric matrices. Full article
(This article belongs to the Special Issue Pretreatment and Bioconversion of Crop Residues)
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15 pages, 1823 KiB  
Article
Recovery of High Purity Lignin and Digestible Cellulose from Oil Palm Empty Fruit Bunch Using Low Acid-Catalyzed Organosolv Pretreatment
by Kinanthi Mondylaksita, Jorge A. Ferreira, Ria Millati, Wiratni Budhijanto, Claes Niklasson and Mohammad J. Taherzadeh
Agronomy 2020, 10(5), 674; https://doi.org/10.3390/agronomy10050674 - 11 May 2020
Cited by 31 | Viewed by 4578
Abstract
The lignocellulosic residue from the palm oil industry, oil palm empty fruit bunch (OPEFB), represents a challenge to both producing industries and environment due to its disposal difficulties. Alternatively, OPEFB can be used for the production of valuable products if pretreatment methods, which [...] Read more.
The lignocellulosic residue from the palm oil industry, oil palm empty fruit bunch (OPEFB), represents a challenge to both producing industries and environment due to its disposal difficulties. Alternatively, OPEFB can be used for the production of valuable products if pretreatment methods, which overcome OPEFB recalcitrance and allow tailored valorization of all its carbohydrates and lignin, are developed. Specifically, high-value applications for lignin, to increase its contribution to the feasibility of lignocellulosic biorefineries, demand high-purity fractions. In this study, acid-catalyzed organosolv using ethanol as a solvent was used for the recovery of high-purity lignin and digestible cellulose. Factors including catalyst type and its concentration, temperature, retention time, and solid-to-liquid (S/L) ratio were found to influence lignin purity and recovery. At the best conditions (0.07% H2SO4, 210 °C, 90 min, and S/L ratio of 1:10), a lignin purity and recovery of 70.6 ± 4.9% and 64.94 ± 1.09%, respectively, were obtained in addition to the glucan-rich fraction. The glucan-rich fraction showed 94.06 ± 4.71% digestibility within 18 h at an enzyme loading of 30 filter paper units (FPU) /g glucan. Therefore, ethanol organosolv can be used for fractionating OPEFB into three high-quality fractions (glucan, lignin, and hemicellulosic compounds) for further tailored biorefining using low acid concentrations. Especially, the use of ethanol opens the possibility for integration of 1st and 2nd generation ethanol benefiting from the separation of high-purity lignin. Full article
(This article belongs to the Special Issue Pretreatment and Bioconversion of Crop Residues)
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23 pages, 3168 KiB  
Article
The Impact of Herbicide Application and Defoliation on Barley Grass (Hordeum murinum subsp. glaucum) Management in Mixed Pasture Legumes
by Jane E. Kelly, Allison J. Chambers, Paul A. Weston, William B. Brown, Wayne A. Robinson, John C. Broster and Leslie A. Weston
Agronomy 2020, 10(5), 671; https://doi.org/10.3390/agronomy10050671 - 11 May 2020
Cited by 2 | Viewed by 3397
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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15 pages, 6319 KiB  
Article
Exogenous Melatonin Improves Salt Tolerance by Mitigating Osmotic, Ion, and Oxidative Stresses in Maize Seedlings
by Jianhong Ren, Jun Ye, Lina Yin, Gouxia Li, Xiping Deng and Shiwen Wang
Agronomy 2020, 10(5), 663; https://doi.org/10.3390/agronomy10050663 - 8 May 2020
Cited by 49 | Viewed by 4056
Abstract
Melatonin has been confirmed extensively for the positive effects on increasing plant tolerance to various abiotic stresses. However, the roles of melatonin in mediating different stresses still need to be explored in different plants species and growth periods. To investigate the role of [...] Read more.
Melatonin has been confirmed extensively for the positive effects on increasing plant tolerance to various abiotic stresses. However, the roles of melatonin in mediating different stresses still need to be explored in different plants species and growth periods. To investigate the role of melatonin in mitigating salt stress, maize (Zea mays L.) seedlings growing in hydroponic solution were treated with 100 mM NaCl combined with or without 1 μM melatonin. Melatonin application had no effects on maize growth under normal condition, while it moderately alleviated the NaCl-induced inhibition of plant growth. The leaf area, biomass, and photosynthesis of melatonin-treated plants were higher than that of without melatonin under NaCl treatment. The osmotic potential was lower, and the osmolyte contents (including sucrose and fructose) were higher in melatonin-treated plants. Meanwhile, the decreases in Na+ content and increases in K+/Na+ ratio were found in shoots of melatonin-applied plant under salt stress. Moreover, both enzymatic and nonenzymatic antioxidant activities were significantly increased in leaves with melatonin application under salt treatment. These results clearly indicate that the exogenous melatonin-enhanced salt tolerance under short-term treatment could be ascribed to three aspects, including osmotic adjustment, ion balance, and alleviation of salt-induced oxidative stress. Full article
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18 pages, 1858 KiB  
Article
Effect of Row Spacing, Sowing Density, and Harvest Time on Floret Yield and Yield Components of Two Safflower Cultivars Grown in Southwestern Germany
by Kathrin Steberl, Jens Hartung, Sebastian Munz and Simone Graeff-Hönninger
Agronomy 2020, 10(5), 664; https://doi.org/10.3390/agronomy10050664 - 8 May 2020
Cited by 13 | Viewed by 4502
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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18 pages, 809 KiB  
Review
Interaction between Humic Substances and Plant Hormones for Phosphorous Acquisition
by Keiji Jindo, Luciano Pasqualoto Canellas, Alfonso Albacete, Lidiane Figueiredo dos Santos, Rafael Luiz Frinhani Rocha, Daiane Carvalho Baia, Natália Oliveira Aguiar Canellas, Travis Luc Goron and Fábio Lopes Olivares
Agronomy 2020, 10(5), 640; https://doi.org/10.3390/agronomy10050640 - 1 May 2020
Cited by 44 | Viewed by 8358
Abstract
Phosphorus (P) deficiency is a major constraint in highly weathered tropical soils. Although phosphorous rock reserves may last for several hundred years, there exists an urgent need to research efficient P management for sustainable agriculture. Plant hormones play an important role in regulating [...] Read more.
Phosphorus (P) deficiency is a major constraint in highly weathered tropical soils. Although phosphorous rock reserves may last for several hundred years, there exists an urgent need to research efficient P management for sustainable agriculture. Plant hormones play an important role in regulating plant growth, development, and reproduction. Humic substances (HS) are not only considered an essential component of soil organic carbon (SOC), but also well known as a biostimulant which can perform phytohormone-like activities to induce nutrient uptake. This review paper presents an overview of the scientific outputs in the relationship between HS and plant hormones. Special attention will be paid to the interaction between HS and plant hormones for nutrient uptake under P-deficient conditions. Full article
(This article belongs to the Special Issue Hormone Signaling and Regulation in Cultivated Plants)
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18 pages, 1867 KiB  
Review
Remote Sensing for Precision Agriculture: Sentinel-2 Improved Features and Applications
by Joel Segarra, Maria Luisa Buchaillot, Jose Luis Araus and Shawn C. Kefauver
Agronomy 2020, 10(5), 641; https://doi.org/10.3390/agronomy10050641 - 1 May 2020
Cited by 222 | Viewed by 50726
Abstract
The use of satellites to monitor crops and support their management is gathering increasing attention. The improved temporal, spatial, and spectral resolution of the European Space Agency (ESA) launched Sentinel-2 A + B twin platform is paving the way to their popularization in [...] Read more.
The use of satellites to monitor crops and support their management is gathering increasing attention. The improved temporal, spatial, and spectral resolution of the European Space Agency (ESA) launched Sentinel-2 A + B twin platform is paving the way to their popularization in precision agriculture. Besides the Sentinel-2 A + B constellation technical features the open-access nature of the information they generate, and the available support software are a significant improvement for agricultural monitoring. This paper was motivated by the challenges faced by researchers and agrarian institutions entering this field; it aims to frame remote sensing principles and Sentinel-2 applications in agriculture. Thus, we reviewed the features and uses of Sentinel-2 in precision agriculture, including abiotic and biotic stress detection, and agricultural management. We also compared the panoply of satellites currently in use for land remote sensing that are relevant for agriculture to the Sentinel-2 A + B constellation features. Contrasted with previous satellite image systems, the Sentinel-2 A + B twin platform has dramatically increased the capabilities for agricultural monitoring and crop management worldwide. Regarding crop stress monitoring, Sentinel-2 capacities for abiotic and biotic stresses detection represent a great step forward in many ways though not without its limitations; therefore, combinations of field data and different remote sensing techniques may still be needed. We conclude that Sentinel-2 has a wide range of useful applications in agriculture, yet still with room for further improvements. Current and future ways that Sentinel-2 can be utilized are also discussed. Full article
(This article belongs to the Special Issue Precision Agriculture)
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18 pages, 5387 KiB  
Article
Beneficial Effects of Biochar and Chitosan on Antioxidative Capacity, Osmolytes Accumulation, and Anatomical Characters of Water-Stressed Barley Plants
by Yaser Hafez, Kotb Attia, Salman Alamery, Abdelhalim Ghazy, Abdullah Al-Doss, Eid Ibrahim, Emad Rashwan, Lamiaa El-Maghraby, Ahmed Awad and Khaled Abdelaal
Agronomy 2020, 10(5), 630; https://doi.org/10.3390/agronomy10050630 - 29 Apr 2020
Cited by 119 | Viewed by 5875
Abstract
The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll [...] Read more.
The impact of biochar and chitosan on barley plants under drought stress conditions was investigated during two field experiments. Our results confirmed that drought stress negatively affected morphological and physiological growth traits of barley plants such as plant height, number of leaves, chlorophyll concentrations, and relative water content. However, electrolyte leakage (EL%), lipid peroxidation (MDA), soluble sugars, sucrose and starch contents significantly increased as a response to drought stress. Additionally, 1000 grain weight, grains yield ha−1 and biological yield significantly decreased in stressed barley plants, also anatomical traits such as upper epidermis, lower epidermis, lamina, and mesophyll tissue thickness as well as vascular bundle diameter of flag leaves significantly decreased compared with control. The use of biochar and chitosan led to significant increases in plant height, number of leaves, and chlorophyll concentrations as well as relative water content; nevertheless these treatments led to significant decreases in electrolyte leakage (EL%) and lipid peroxidation (MDA) in the stressed plants. Moreover, anatomical and yield characters of stressed barley plants were improved with application of biochar and chitosan. The results proved the significance of biochar and chitosan in alleviating the damaging impacts of drought on barley plants. Full article
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14 pages, 2520 KiB  
Article
Relations between Circular Economic “Principles” and Organic Food Purchasing Behavior in Hungary
by Csaba Fogarassy, Kinga Nagy-Pércsi, Sinazo Ajibade, Csaba Gyuricza and Prespa Ymeri
Agronomy 2020, 10(5), 616; https://doi.org/10.3390/agronomy10050616 - 26 Apr 2020
Cited by 38 | Viewed by 4526
Abstract
Because of the climate change and emerging need for an environmentally sustainable production system, circular economic characteristics have come to the front in many studies. There are many challenges in this shift toward a circular value chain. Still, it is unquestionable that the [...] Read more.
Because of the climate change and emerging need for an environmentally sustainable production system, circular economic characteristics have come to the front in many studies. There are many challenges in this shift toward a circular value chain. Still, it is unquestionable that the analysis of consumers’ behaviour is crucial, because without their engagement, circular systems cannot work correctly. This article aimed to explore the circular characteristics of consumers’ attitude towards food purchasing in Hungary. Factor and cluster analyses were applied for market segmentation. The question to be answered was the following: “Are there any segments in the Hungarian food market that can be aimed at by different marketing tools to promote circular systems?” The hypothesis was that well-defined segments can be separated, garnering more engagement in the circular value chain in Hungary. We could separate two clusters, in which the members’ opinions were in line with the circular economic characteristics. Summing up the features of the different clusters, we can state that the members in cluster 1 (“Information-dependent”) and cluster 3 (“Direct purchasers”) were in the most local dimension; their attitude was the most adequate for the circular economic values. The “Information-dependent” consumer in particular was remarkable from the aspect of this investigation. This study showed that highly educated young people, who are very conscious consumers and live on good incomes, may be the target group for circular innovation. These young consumers usually buy organic food, are confident internet and software users, live in cities, and follow a healthy lifestyle. Finding the right marketing tools to integrate these consumers into more sustainable circular systems effectively and to be committed to the concepts of circular consumption is an essential mission in the future. Collecting from different databases and continuously analysing consumer feedback can be a huge step towards in achieving sustainable consumption and avoiding food waste. The significance of this analysis was that we found a defined segment that represents propensity towards accepting circular economy values and can be the target group of policies integrating circular systems. Full article
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19 pages, 3027 KiB  
Article
Exploring the Genetic Architecture of Root-Related Traits in Mediterranean Bread Wheat Landraces by Genome-Wide Association Analysis
by Rubén Rufo, Silvio Salvi, Conxita Royo and Jose Miguel Soriano
Agronomy 2020, 10(5), 613; https://doi.org/10.3390/agronomy10050613 - 25 Apr 2020
Cited by 21 | Viewed by 3949
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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19 pages, 7679 KiB  
Article
Deep Phenotyping of Yield-Related Traits in Wheat
by Lukas Prey and Urs Schmidhalter
Agronomy 2020, 10(4), 603; https://doi.org/10.3390/agronomy10040603 - 23 Apr 2020
Cited by 7 | Viewed by 4144
Abstract
The complex formation of grain yield (GY) is related to multiple dry matter (DM) traits; however, due to their time-consuming determination, they are not readily accessible. In winter wheat (Triticum aestivum L.), both agronomic treatments and genotypic variation influence GY in interaction [...] Read more.
The complex formation of grain yield (GY) is related to multiple dry matter (DM) traits; however, due to their time-consuming determination, they are not readily accessible. In winter wheat (Triticum aestivum L.), both agronomic treatments and genotypic variation influence GY in interaction with the environment. Spectral proximal sensing is promising for high-throughput non-destructive phenotyping but was rarely evaluated systematically for dissecting yield-related variation in DM traits. Aiming at a temporal, spectral and organ-level optimization, 48 vegetation indices were evaluated in a high-yielding environment in 10 growth stages for the estimation of 31 previously compared traits related to GY formation—influenced by sowing time, fungicide, N fertilization, and cultivar. A quantitative index ranking was evaluated to assess the stage-independent index suitability. GY showed close linear relationships with spectral vegetation indices across and within agronomic treatments (R2 = 0.47–0.67 ***). Water band indices, followed by red edge-based indices, best used at milk or early dough ripeness, were better suited than the widely used normalized difference vegetation index (NDVI). Index rankings for many organ-level DM traits were comparable, but the relationships were often less close. Among yield components, grain number per spike (R2 = 0.24–0.34 ***) and spike density (R2 = 0.23–0.46 ***) were moderately estimated. GY was mainly estimated by detecting total DM rather than the harvest index. Across agronomic treatments and cultivars, seasonal index rankings were the most stable for GY and total DM, whereas traits related to DM allocation and translocation demanded specific index selection. The results suggest using indices with water bands, near infrared/red edge and visible light bands to increase the accuracy of in-season spectral phenotyping for GY, contributing organ-level traits, and yield components, respectively. Full article
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17 pages, 2332 KiB  
Article
Phenolic Content, Color Development, and Pigment−Related Gene Expression: A Comparative Analysis in Different Cultivars of Strawberry during the Ripening Process
by Carolina Parra-Palma, Luis Morales-Quintana and Patricio Ramos
Agronomy 2020, 10(4), 588; https://doi.org/10.3390/agronomy10040588 - 20 Apr 2020
Cited by 33 | Viewed by 4383
Abstract
Globally, the strawberry is one of the most widely consumed fruits, but under certain environmental conditions, it exhibits inadequate red color development, causing economic losses due to lower product quality. In order to evaluate if changes in color are cultivar-specific and environmentally dependent, [...] Read more.
Globally, the strawberry is one of the most widely consumed fruits, but under certain environmental conditions, it exhibits inadequate red color development, causing economic losses due to lower product quality. In order to evaluate if changes in color are cultivar-specific and environmentally dependent, a comparative study of anthocyanin accumulation, total phenolic, total flavonoid content analysis and additionally a transcriptional profile of pigment-related genes in “Camarosa,” “Cristal,” “Monterey,” and “Portola” (four strawberry cultivars) was performed. These showed an increase in their red coloration during fruit development. The anthocyanin accumulation in the four cultivars was related to the particular progress of the transcriptional activity of genes involved in the biosynthesis of flavonoid pigments. The greatest increase was observed in “Monterey” and “Camarosa”; thus, we have found a correlation between fruit color redness and total anthocyanins only in these cultivars. However, a positive correlation between the mRNA abundance of FaF3′H and FaFLS and the total flavonoids content was found in all cultivars at early stages of ripening. Finally, we found correlations between color and other important physiological properties such as SSC/TA, weight, and aroma expressed as total esters. These results could be useful in making decisions in future breeding programs to improve the content of healthy compound content in strawberry fruit. Full article
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21 pages, 1942 KiB  
Review
Accelerating Genetic Gain in Sugarcane Breeding Using Genomic Selection
by Seema Yadav, Phillip Jackson, Xianming Wei, Elizabeth M. Ross, Karen Aitken, Emily Deomano, Felicity Atkin, Ben J. Hayes and Kai P. Voss-Fels
Agronomy 2020, 10(4), 585; https://doi.org/10.3390/agronomy10040585 - 19 Apr 2020
Cited by 57 | Viewed by 9861
Abstract
Sugarcane is a major industrial crop cultivated in tropical and subtropical regions of the world. It is the primary source of sugar worldwide, accounting for more than 70% of world sugar consumption. Additionally, sugarcane is emerging as a source of sustainable bioenergy. However, [...] Read more.
Sugarcane is a major industrial crop cultivated in tropical and subtropical regions of the world. It is the primary source of sugar worldwide, accounting for more than 70% of world sugar consumption. Additionally, sugarcane is emerging as a source of sustainable bioenergy. However, the increase in productivity from sugarcane has been small compared to other major crops, and the rate of genetic gains from current breeding programs tends to be plateauing. In this review, some of the main contributors for the relatively slow rates of genetic gain are discussed, including (i) breeding cycle length and (ii) low narrow-sense heritability for major commercial traits, possibly reflecting strong non-additive genetic effects involved in quantitative trait expression. A general overview of genomic selection (GS), a modern breeding tool that has been very successfully applied in animal and plant breeding, is given. This review discusses key elements of GS and its potential to significantly increase the rate of genetic gain in sugarcane, mainly by (i) reducing the breeding cycle length, (ii) increasing the prediction accuracy for clonal performance, and (iii) increasing the accuracy of breeding values for parent selection. GS approaches that can accurately capture non-additive genetic effects and potentially improve the accuracy of genomic estimated breeding values are particularly promising for the adoption of GS in sugarcane breeding. Finally, different strategies for the efficient incorporation of GS in a practical sugarcane breeding context are presented. These proposed strategies hold the potential to substantially increase the rate of genetic gain in future sugarcane breeding. Full article
(This article belongs to the Special Issue Herbaceous Field Crops Cultivation)
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20 pages, 4226 KiB  
Article
Land Suitability Assessment and Agricultural Production Sustainability Using Machine Learning Models
by Ruhollah Taghizadeh-Mehrjardi, Kamal Nabiollahi, Leila Rasoli, Ruth Kerry and Thomas Scholten
Agronomy 2020, 10(4), 573; https://doi.org/10.3390/agronomy10040573 - 17 Apr 2020
Cited by 112 | Viewed by 10374
Abstract
Land suitability assessment is essential for increasing production and planning a sustainable agricultural system, but such information is commonly scarce in the semi-arid regions of Iran. Therefore, our aim is to assess land suitability for two main crops (i.e., rain-fed wheat and barley) [...] Read more.
Land suitability assessment is essential for increasing production and planning a sustainable agricultural system, but such information is commonly scarce in the semi-arid regions of Iran. Therefore, our aim is to assess land suitability for two main crops (i.e., rain-fed wheat and barley) based on the Food and Agriculture Organization (FAO) “land suitability assessment framework” for 65 km2 of agricultural land in Kurdistan province, Iran. Soil samples were collected from genetic layers of 100 soil profiles and the physical-chemical properties of the soil samples were analyzed. Topography and climate data were also recorded. After calculating the land suitability classes for the two crops, they were mapped using machine learning (ML) and traditional approaches. The maps predicted by the two approaches revealed notable differences. For example, in the case of rain-fed wheat, results showed the higher accuracy of ML-based land suitability maps compared to the maps obtained by traditional approach. Furthermore, the findings indicated that the areas with classes of N2 (≈18%↑) and S3 (≈28%↑) were higher and area with the class N1 (≈24%↓) was less predicted in the traditional approach compared to the ML-based approach. The major limitations of the study area were rainfall at the flowering stage, severe slopes, shallow soil depth, high pH, and large gravel content. Therefore, to increase production and create a sustainable agricultural system, land improvement operations are suggested. Full article
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20 pages, 560 KiB  
Article
Zinc Oxide and Silicone Nanoparticles to Improve the Resistance Mechanism and Annual Productivity of Salt-Stressed Mango Trees
by Nabil I. Elsheery, Mohamed N. Helaly, Hanan M. El-Hoseiny and Shamel M. Alam-Eldein
Agronomy 2020, 10(4), 558; https://doi.org/10.3390/agronomy10040558 - 12 Apr 2020
Cited by 132 | Viewed by 8544
Abstract
Limited findings have been reported on using nanomaterials to improve tree fruit growth, development, and productivity under various stress conditions. To assess the effect of nanoparticles (NPs) like nano-zinc oxide (nZnO) and nano-silicon (nSi) on mango tree growth, yield, and fruit quality under [...] Read more.
Limited findings have been reported on using nanomaterials to improve tree fruit growth, development, and productivity under various stress conditions. To assess the effect of nanoparticles (NPs) like nano-zinc oxide (nZnO) and nano-silicon (nSi) on mango tree growth, yield, and fruit quality under salinity conditions, a factorial experiment was conducted using twelve treatments; three replicates each. Foliar spray of nZnO (50, 100, and 150 mg/L), nSi (150 and 300 mg/L), their combinations, and distilled water as a control was applied at full bloom and one month after of salt-stressed “Ewais” mango trees. Trees positively responded to different levels of nZnO and nSi. Plant growth, nutrients uptake, and carbon assimilation have improved with all treatments, except the higher concentration of nSi. Plant response to stress conditions was represented by a high level of proline content with all treatments, but changes in the activity of the antioxidant enzymes were positively related to the lower and medium concentrations of NPs. Flower malformation has significantly decreased, and the annual fruit yield and physiochemical characteristics have improved with all treatments. It could be recommended that a combination of 100 mg/L nZnO and 150 mg/L nSi improves mango tree resistance, annual crop load, and fruit quality under salinity conditions. Full article
(This article belongs to the Section Horticultural and Floricultural Crops)
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15 pages, 2001 KiB  
Article
Soybean Seed Vigor: Uniformity and Growth as Key Factors to Improve Yield
by Luciano Antônio Ebone, Andréia Caverzan, Alberto Tagliari, José Luís Trevizan Chiomento, Diógenes Cecchin Silveira and Geraldo Chavarria
Agronomy 2020, 10(4), 545; https://doi.org/10.3390/agronomy10040545 - 10 Apr 2020
Cited by 47 | Viewed by 7688
Abstract
Emergence uniformity and the time required for emergence are essential factors for obtaining highly productive potential in plants. Factors such as sowing depth and soil moisture affect uniformity and emergence, but little is known about the impacts of seed vigor. Thus, we determined [...] Read more.
Emergence uniformity and the time required for emergence are essential factors for obtaining highly productive potential in plants. Factors such as sowing depth and soil moisture affect uniformity and emergence, but little is known about the impacts of seed vigor. Thus, we determined the impacts of seed vigor on uniformity and growth as well as development and yield in soybean (Glycine max [L.] Merrill) plants. The treatments consisted of four vigor levels (89%, 57%, 47%, and 43%) obtained by accelerated aging, in a randomized block design, with five replicates at three sites. Seeds with the highest vigor level showed higher uniformity and faster emergence. Dominated plants through their phenotypic plasticity modify stem diameter and internode length. The plants that emerged earlier had a larger leaf area in the three stages (V1, V4, and R2), allowing them to accumulate more photoassimilates in the initial stages. Consequently, these plants exhibited an increase in yield components, especially in the number of fertile nodes and the number of pods per plant, making them more productive. Full article
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23 pages, 6720 KiB  
Article
Optimizing Training Population Size and Content to Improve Prediction Accuracy of FHB-Related Traits in Wheat
by Emmanuel Adeyemo, Prabin Bajgain, Emily Conley, Ahmad H. Sallam and James A. Anderson
Agronomy 2020, 10(4), 543; https://doi.org/10.3390/agronomy10040543 - 9 Apr 2020
Cited by 8 | Viewed by 3015
Abstract
Genomic selection combines phenotypic and molecular marker data from a training population to predict the genotypic values of untested lines. It can improve breeding efficiency as large pools of untested lines can be evaluated for selection. Training population (TP) composition is one of [...] Read more.
Genomic selection combines phenotypic and molecular marker data from a training population to predict the genotypic values of untested lines. It can improve breeding efficiency as large pools of untested lines can be evaluated for selection. Training population (TP) composition is one of the most important factors affecting the accuracy of genomic prediction. The University of Minnesota wheat breeding program implements genomic selection at the F5 stage for Fusarium head blight (FHB) resistance. This study used field data for FHB resistance in wheat (Triticum aestivum L.) to investigate the use of small-size TPs designed with and without stratified sampling for three FHB traits in three different F5 populations (TP17, TP18, and TP19). We also compared the accuracies of these two TP design methods with the accuracy obtained from a large size TP. Lastly, we evaluated the impact on trait predictions when the parents of F5 lines were included in the TP. We found that the small size TP selected randomly, without stratification, had the lowest predictive ability across the three F5 populations and across the three traits. This trend was statistically significant (p = 0.05) for all three traits in TP17 and two traits in TP18. Designing a small-size TP by stratified sampling led to a higher accuracy than a large-size TP in most traits across TP18 and TP19; this is because stratified sampling allowed the selection of a small set of closely related lines. We also observed that the addition of parental lines to the TP and evaluating the TP in two replications led to an increase in predictive abilities in most cases. Full article
(This article belongs to the Special Issue Breeding Healthy Cereals: Genetic Improvement of Fusarium Resistance)
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19 pages, 1892 KiB  
Article
Harvest Season and Genotype Affect Head Quality and Shelf-Life of Ready-to-Use Broccoli
by Giulia Conversa, Corrado Lazzizera, Anna Bonasia and Antonio Elia
Agronomy 2020, 10(4), 527; https://doi.org/10.3390/agronomy10040527 - 7 Apr 2020
Cited by 9 | Viewed by 2766
Abstract
Pre-harvest climatic conditions and genotype may have important effects on head quality and post-harvest performance of fresh-cut broccoli. The present work evaluates the effect of the growing cycle (summer–autumn (SA), winter (W), winter–spring (WS), and spring (S)) and genotype on qualitative (dry matter, [...] Read more.
Pre-harvest climatic conditions and genotype may have important effects on head quality and post-harvest performance of fresh-cut broccoli. The present work evaluates the effect of the growing cycle (summer–autumn (SA), winter (W), winter–spring (WS), and spring (S)) and genotype on qualitative (dry matter, concentration of chlorophylls, carotenoids, and color) and antioxidative (ascorbic acid, dehydroascorbic acid, total phenol concentrations, and antioxidant capacity) traits of broccoli heads and minimally processed florets. The WS raw product showed the best color indices (L* = 38.6, C* = 9.3 and h° = 123.8) as well as the highest chlorophyll (0.23 µg mg−1 fresh weight) but the lowest total phenol concentration (5.5 µg mg−1 dry weight - DW), whereas the ascorbic acid level (2.3 µg mg−1 DW) was comparable to or lower than that the other growing cycles. The WS florets confirmed their best visual quality, even showing an improved total phenol level after 14 days of cold storage. The climatic conditions experienced by broccoli plants grown in SA, W, and S periods were stressful as they resulted in a slight reduction in the visual quality of the heads, though only the SA florets showed a distinctive decay during storage. The lower post-harvest performance of SA grown broccoli was confirmed in all the tested cultivars, despite ‘Naxos’ seeming more tolerant. On the contrary, the greatest content of ascorbic acid (3.2 µg mg−1 DW) in the W heads and of phenols (11.1 µg mg−1 DW) in S heads was maintained during storage, thus preserving floret color. Full article
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8 pages, 498 KiB  
Article
Impact and Control of Powdery Mildew on Irrigated Soybean Varieties Grown in Southeast Australia
by Mathew W Dunn and Luke G Gaynor
Agronomy 2020, 10(4), 514; https://doi.org/10.3390/agronomy10040514 - 3 Apr 2020
Cited by 8 | Viewed by 3241
Abstract
Powdery mildew—caused by the fungus Erisyphe diffusa (syn. Microsphaera diffusa)—was first observed in commercial soybean crops in southern New South Wales (NSW), Australia, in 2011. Its detection raised concerns that soybean production might be constrained if the severity of the disease reached [...] Read more.
Powdery mildew—caused by the fungus Erisyphe diffusa (syn. Microsphaera diffusa)—was first observed in commercial soybean crops in southern New South Wales (NSW), Australia, in 2011. Its detection raised concerns that soybean production might be constrained if the severity of the disease reached the levels observed in northern Australia. Field experiments were conducted over four consecutive seasons to examine the response of three soybean cultivars—Djakal, SnowyA and the breeding line N005A-80—to two fungicides and two fungicide application regimes. The cultivar Djakal was identified as having a high level of resistance to powdery mildew. The severity of infection symptoms varied between seasons. The most severe symptoms were observed during the 2014–2015 season which resulted in the largest grain yield reduction of 20% for the cultivar SnowyA. All fungicide treatments provided a significant reduction in the severity of symptoms, with the split application of tebuconazole and both the single and split applications of tebuconazole + prothioconazole providing the most effective control of the disease. Few other grain yield effects were found, even when strong disease control was achieved. This was a suspected result of the consistent late-in-the-season onset of the disease. Few differences were observed among the treatments in terms of lodging severity, date of physiological maturity, or grain oil and protein concentrations. It was concluded that both fungicides provided effective control of powdery mildew. However, when disease pressure is low, application might not be warranted in southern NSW. Full article
(This article belongs to the Section Pest and Disease Management)
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18 pages, 1026 KiB  
Article
Use of Aloe Vera Gel-Based Edible Coating with Natural Anti-Browning and Anti-Oxidant Additives to Improve Post-Harvest Quality of Fresh-Cut ‘Fuji’ Apple
by Vittorio Farina, Roberta Passafiume, Ilenia Tinebra, Eristanna Palazzolo and Giuseppe Sortino
Agronomy 2020, 10(4), 515; https://doi.org/10.3390/agronomy10040515 - 3 Apr 2020
Cited by 45 | Viewed by 8863
Abstract
Recently, there is increasing use of edible and biodegradable films and packaging that are both environmentally friendly and functional for storage and market distribution. Fresh-cut ‘Fuji’ apples, harvested in an organic farm, were treated, using a spraying technique, with three new edible coatings [...] Read more.
Recently, there is increasing use of edible and biodegradable films and packaging that are both environmentally friendly and functional for storage and market distribution. Fresh-cut ‘Fuji’ apples, harvested in an organic farm, were treated, using a spraying technique, with three new edible coatings based on Aloe vera gel (AVG—40% v/w) and in combination with natural additives: lemon essential oil (LEO—1% v/w) and hydroxypropyl methylcellulose (HPMC—0.1% v/w) and compared with untreated sample (CTR), the physicochemical and sensory characteristics and the proximate compounds were evaluated. During cold storage, weight loss, soluble solids content, and color of uncoated slices were reduced, while softening, ripening, browning, and acidity were accelerated. In contrast, the AVG/HPMC treatment significantly delayed the above parameters related to post-harvest quality loss, while the AVG/LEO treatment delayed the browning processes, maintaining an excellent color during cold storage. Concerning proximate compounds, the treatments did not alter their concentration in the fruit tissues. Sensory analyses revealed no detrimental effect on taste, aroma, or flavor. Our data evidenced the positive effect of Aloe vera gel in combination with LEO and HPMC on fresh-cut apple quality as an innovative and sustainable technique to maintain fresh-cut apple quality. Full article
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