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Agronomy, Volume 11, Issue 12 (December 2021) – 228 articles

Cover Story (view full-size image): Tetraploid plants are very useful in breeding for improvements in fruit quality and enhancement of stress tolerances. Satsuma mandarin (Citrus unshiu Marcow.) is an economically important fruit crop in Japan; however, global warming is negatively affecting the fruit quality of this species in recent years, resulting in problems such as coloring disorder, rind puffing and bland taste. In this study, a morphological investigation and a reproductive assessment of autotetraploid Satsuma mandarin were carried out. Compared to the diploid, the tetraploid had significantly thick and round leaves, large flowers and pollen grains. The tetraploid had a higher content of carotenoids in the flavedo than diploid, and the rind color was much better. Pollen fertility of the tetraploid was high compared with the diploid, so the triploid progenies could be obtained in crossing with diploid cultivars. View this paper
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Article
Analysis of the Content Values of Sweet Maize (Zea mays L. Convar Saccharata Koern) in Precision Farming
Agronomy 2021, 11(12), 2596; https://doi.org/10.3390/agronomy11122596 - 20 Dec 2021
Viewed by 1039
Abstract
The global precision farming area is constantly increasing, and precision sweet maize production developed the most. Sweet maize yield is above average in precision farming. Additionally, its role in healthy nutrition is becoming increasingly important due to new hybrids with high carotenoid content. [...] Read more.
The global precision farming area is constantly increasing, and precision sweet maize production developed the most. Sweet maize yield is above average in precision farming. Additionally, its role in healthy nutrition is becoming increasingly important due to new hybrids with high carotenoid content. Precision farming techniques are needed to produce healthy food. In particular, nutrient supply and irrigation, sowing, crop management and harvesting need to be carried out with precision techniques. These factors are all prerequisites for effective and healthy growing and processing. The aim was to use the yields of the four sweet maize hybrids grown on the largest area to examine their nutritional values and concentrations (mg kg−1 dry matter) and to analyse their yield per hectare. Concentration is important for the consumer because K, P, Mg, Ca, Fe, Zn, and Na play an important role in metabolism, skin protection, and bone and tooth health. The new results obtained show that the amount of lutein and zeaxanthin per hectare is important for the processing industry, especially for use in food supplements. Their anti-inflammatory effects and their role in disease prevention (cardiovascular diseases, Age-Related Macular Degeneration (AMD)) have been demonstrated. Consumers choose sweet maize mainly on the basis of its palatability, which is why the sugar content of the hybrids was also studied. We assumed that the element concentration in the yield of new hybrids with higher yield per hectare does not decrease with increasing yield. The concentrations of zeaxanthin, β-cryptoxanthin and β-carotene appear in one principal component and they are in close positive correlation with each other. The lutein concentration was independent of the former three compounds. The independence of the lutein concentration means that it is not possible to estimate its amount based on the other three components. For yield per unit area, the correlation is one-dimensional. Yield determines the lutein, zeaxanthin, β-cryptoxanthin and β-carotene concentrations per hectare. Full article
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Article
Towards Sustainable Dairy Production in Argentina: Evaluating Nutrient and CO2 Release from Raw and Processed Farm Waste
Agronomy 2021, 11(12), 2595; https://doi.org/10.3390/agronomy11122595 - 20 Dec 2021
Cited by 1 | Viewed by 963
Abstract
Mineralization studies are the first step in determining the usefulness of an amendment such as fertilizer, and are essential to creating guidelines for dairy waste management to help producers make informed decisions. Our goal was to assess the effects of dairy raw, composted, [...] Read more.
Mineralization studies are the first step in determining the usefulness of an amendment such as fertilizer, and are essential to creating guidelines for dairy waste management to help producers make informed decisions. Our goal was to assess the effects of dairy raw, composted, and digested manure amendments on C, N, and P mineralization to evaluate the feasibility of their in-farm production and use as organic fertilizers. The liquid and solid fractions of dairy effluent (LDE, SDE), dairy effluent digestate (DED), onion–cattle manure digestate and compost (OCMD, OCMC) were characterized by chemical and spectroscopic methods. Soil microcosms with LDE, SDE, DED, OCMD and OCMC and the C, N and P mineralization were determined periodically. Elemental and structural differences among amendments led to contrasting profiles of C, N, and P mineralization, and thus to differences in nutrient availability, immobilization, and CO2 emission. All processed materials were more stable than untreated waste, reducing C emissions. Digestates showed net C immobilization, and supplied the highest levels of available N, creating a relative P deficit. Instead, the compost supplied N and P via mineralization, producing a relative P excess. Future studies should aim at evaluating fertilization strategies that combine both kinds of amendments, to exploit their complimentary agronomic characteristics. Full article
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Article
Influence of Geometry in the Behavior of Disc-Shaped Mechanical Energy Absorbers for Agricultural Tractors
Agronomy 2021, 11(12), 2594; https://doi.org/10.3390/agronomy11122594 - 20 Dec 2021
Viewed by 725
Abstract
Disc-shaped mechanical energy absorbers (MEAs), in combination with rollover protection structures (ROPSs), may contribute to the prevention of the infringement of the safety zone and the collapse of the ROPS in case of the overturn of an agricultural tractor. An MEA can absorb [...] Read more.
Disc-shaped mechanical energy absorbers (MEAs), in combination with rollover protection structures (ROPSs), may contribute to the prevention of the infringement of the safety zone and the collapse of the ROPS in case of the overturn of an agricultural tractor. An MEA can absorb a significant amount of potential energy of an overturning tractor and its deformation produces a rotation of the ROPS around the safety zone. In this research, MEAs with two different geometries have been developed. Both geometries present common features, such as disc dimensions, number of rings, and number of arms, but the distribution of the arms differs. Additionally, these MEA were manufactured in steel discs of four different thicknesses, ranging from 2 to 6 mm. The manufactured MEAs were tested in a universal testing machine, and their behavior characterized. From this data, linear models of the MEAs were developed. As a consequence, a number of characteristic parameters were selected and calculated, such as the activation load and the strain energy absorbed in a safe range of applied loads. Some patterns and trends were analyzed from the tested MEAs, which enables a better description of their behavior and the extrapolation of this behavior to other non-tested thicknesses and geometries. Full article
(This article belongs to the Section Agricultural Biosystem and Biological Engineering)
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Article
Agronomic Efficiency Losses by Ammonia Emission from Staple Crops in China as Response to Various Mitigation Strategies: A Meta-Analysis Study
Agronomy 2021, 11(12), 2593; https://doi.org/10.3390/agronomy11122593 - 20 Dec 2021
Viewed by 931
Abstract
Economic losses and environmental hazards are meaningful problems of emitted ammonia induced by extensive use of synthetic nitrogen fertilizers. The concept presented as yield scaled fertilizer productivity (YSFP) in our meta-analysis in addition to nitrogen use efficiency (NUE), nitrogen agronomic efficiency (NAE), and [...] Read more.
Economic losses and environmental hazards are meaningful problems of emitted ammonia induced by extensive use of synthetic nitrogen fertilizers. The concept presented as yield scaled fertilizer productivity (YSFP) in our meta-analysis in addition to nitrogen use efficiency (NUE), nitrogen agronomic efficiency (NAE), and productivity of applied nitrogen (PAN) were used to weight ammonia emission (AV)-induced reductions in wheat, maize, and rice production. The comprehensive meta-analysis was used to weight the reductions in these parameters by AV as the difference between observed means of the collected studies and their adjusted means using AV factor. There were higher reductions in agronomic production induced by AV in rice than maize and wheat. AV-induced reductions in PAN of rice, maize, and wheat were decreased by 4.99, 3.71, and 2.42 (kg grains kg−1 N), respectively. YSFP and PAN recorded the highest sensitivity to AV in wheat (R2 = 0.88 for both) and rice (R2 = 0.92 and 0.89, respectively), while NUE was the most efficient parameter in weighting AV induced agronomic effects in maize (R2 = 0.81). Slow-released N fertilizers resulted in the lowest reductions in AV induced agronomic losses followed by organic amendments and then urea while using other synthetic fertilizers recorded the highest reductions by 3.90, 6.40, 1.41, and 4.70 in YSFP, NUE, NAE, and PAN, respectively. Inhibitors had the highest effect on mitigating AV induced agronomic losses compared with biochar and mulching and affected the parameters following that order as percentages of no amendments, YSFP (52.63%) > PAN (47.18%) > NUE (40.83%) > NAE (38.75%). This study outlines the reductions in agronomic production induced by AV and weights the efficiency of various mitigation strategies under various agronomic conditions. The results proved the efficiency of YSFP with NUE parameters to weight the effect of AV on crop yield, while suggesting to find out more applicable parameters in further studies. Full article
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Article
Improving Nitrogen Status Estimation in Malting Barley Based on Hyperspectral Reflectance and Artificial Neural Networks
Agronomy 2021, 11(12), 2592; https://doi.org/10.3390/agronomy11122592 - 20 Dec 2021
Viewed by 924
Abstract
Malting barley requires sensitive methods for N status estimation during the vegetation period, as inadequate N nutrition can significantly limit yield formation, while overfertilization often leads to an increase in grain protein content above the limit for malting barley and also to excessive [...] Read more.
Malting barley requires sensitive methods for N status estimation during the vegetation period, as inadequate N nutrition can significantly limit yield formation, while overfertilization often leads to an increase in grain protein content above the limit for malting barley and also to excessive lodging. We hypothesized that the use of N nutrition index and N uptake combined with red-edge or green reflectance would provide extended linearity and higher accuracy in estimating N status across different years, genotypes, and densities, and the accuracy of N status estimation will be further improved by using artificial neural network based on multiple spectral reflectance wavelengths. Multifactorial field experiments on interactive effects of N nutrition, sowing density, and genotype were conducted in 2011–2013 to develop methods for estimation of N status and to reduce dependency on changing environmental conditions, genotype, or barley management. N nutrition index (NNI) and total N uptake were used to correct the effect of biomass accumulation and N dilution during plant development. We employed an artificial neural network to integrate data from multiple reflectance wavelengths and thereby eliminate the effects of such interfering factors as genotype, sowing density, and year. NNI and N uptake significantly reduced the interannual variation in relationships to vegetation indices documented for N content. The vegetation indices showing the best performance across years were mainly based on red-edge and carotenoid absorption bands. The use of an artificial neural network also significantly improved the estimation of all N status indicators, including N content. The critical reflectance wavelengths for neural network training were in spectral bands 400–490, 530–570, and 710–720 nm. In summary, combining NNI or N uptake and neural network increased the accuracy of N status estimation to up 94%, compared to less than 60% for N concentration. Full article
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Article
The Effect of Titanium Organic Complex on Pollination Process and Fruit Development of Apple cv. Topaz
Agronomy 2021, 11(12), 2591; https://doi.org/10.3390/agronomy11122591 - 20 Dec 2021
Viewed by 912
Abstract
Optimal weather conditions are necessary for the proper course of the flowering process and high activity of pollinators, which is the most important factor affecting pollination. Because weather conditions do not always favour effective pollination and because pollinators’ activities are decreasing, the application [...] Read more.
Optimal weather conditions are necessary for the proper course of the flowering process and high activity of pollinators, which is the most important factor affecting pollination. Because weather conditions do not always favour effective pollination and because pollinators’ activities are decreasing, the application of compound stimulating pollination and fertilization may be a good perspective for increasing yield. Titanium is considered a beneficial element for plants. Preliminary studies have indicated the positive effect of titanium organic complex on pollen adhesion to the stigma and pollen germination on the stigma of tomato and cucumber. Therefore, a 2-year experiment was designed to determine the effect of titanium organic complex application on the pollination process and fruit development of apple cv. Topaz (Malus domestica Borkh.) The experiment demonstrated the positive effect of titanium organic complex on fertilization of ovules because of effective pollination, seed setting, and fruit development of apple. Application of titanium organic complex improved pollen adhesion to the stigma and pollen germination on the stigma. In addition, titanium organic complex increased the number of pollen tubes growing through the pistil style, which resulted in fertilization that was more effective, as confirmed by the higher number of seeds set in fruits. Higher numbers of seeds set in fruits positively affected their weight and size. Therefore, fruit harvested from trees to which titanium organic complex was applied were characterized by greater weight, length, and diameter compared to fruits obtained from the trees to which titanium organic complex was not applied. Full article
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Review
Coffee Leaf Rust (Hemileia vastatrix) in Kenya—A Review
Agronomy 2021, 11(12), 2590; https://doi.org/10.3390/agronomy11122590 - 20 Dec 2021
Cited by 2 | Viewed by 1155
Abstract
Coffee is one of the most important cash crops and beverages in the world. Production of coffee is limited by many factors, which include insect pests and diseases, among others. One of the most devastating coffee diseases in many coffee-producing countries is Coffee [...] Read more.
Coffee is one of the most important cash crops and beverages in the world. Production of coffee is limited by many factors, which include insect pests and diseases, among others. One of the most devastating coffee diseases in many coffee-producing countries is Coffee Leaf Rust caused by the fungus Hemileia vastatrix. Kenya is a coffee-producing country and has conducted studies to understand and manage the disease. Management strategies for the disease include the development and use of fungicide spray programs, cultural control practices, breeding resistant coffee varieties, and biological control agents. This paper reviews the status of the disease and management options applied in Kenya. Full article
(This article belongs to the Special Issue Current Status and Management of Coffee Rust Disease)
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Article
Effect of Plant Spacings on Growth, Physiology, Yield and Fiber Quality Attributes of Cotton Genotypes under Nitrogen Fertilization
Agronomy 2021, 11(12), 2589; https://doi.org/10.3390/agronomy11122589 - 19 Dec 2021
Cited by 1 | Viewed by 1061
Abstract
Cotton is a major cash crop of Pakistan that provides high foreign exchange and plays an important role in agriculture, industry, and economic development. The plant population is important in achieving high cotton yield and fiber quality attributes in irrigated conditions. Most farmers [...] Read more.
Cotton is a major cash crop of Pakistan that provides high foreign exchange and plays an important role in agriculture, industry, and economic development. The plant population is important in achieving high cotton yield and fiber quality attributes in irrigated conditions. Most farmers maintain plant spacing according to their local tradition, and often ignore the varietal characteristics in Pakistan that cause low yield and poor quality of products. Therefore, standardization of plant spacings according to varietal characteristics is important to achieve higher yield and fiber quality. A field experiment was carried out at the Agronomic Research Area, Muhammad Nawaz Shareef University of Agriculture, Multan, Pakistan in 2017, in order to evaluate the performance of four cotton cultivars (MNH-1016, FH-Lalazar, NIAB-878, and Cyto-124) under five plant spacings (15.0, 22.5, 30.0, 37.5, and 45.0 cm), comparing them with and without nitrogen application. Nitrogen fertilization was applied at the rate of 197 kg ha−1. The experiment was replicated thrice, as per Randomized Complete Block Design with factorial arrangements. The results showed that nitrogen application of 197 kg ha−1 showed a positive impact on all crop parameters compared to plots where no nitrogen fertilizer was applied. The wider plant spacing (45 cm) increased the values of many cotton parameters compared with other plant spacings (22.5, 30.0, 37.5 and 45.0 cm), but the seed cotton yield was found to be higher in the narrow plant spacing (15 cm). However, fiber quality parameters such as GOT, staple strength, and micronaire showed higher values under wider plant spacing (45.0 cm). The varieties showed a mixed effect on cotton productivity and fiber quality. The MNH-1016 significantly impacted yield-contributing parameters such as bolls plant−1, boll weight and seed cotton yield. The NIAB-878 showed a higher photosynthetic rate and stomatal conductance compared to other varieties. Therefore, the wider plant spacing with nitrogen application could be a better strategy to increase cotton growth, yield, physiology, and fiber quality. However, long-term studies under different climatic conditions are suggested for wider plant spacing with nitrogen fertilizers. Full article
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Article
Germinated Chickpea and Lupin as Promising Ingredients for Breadmaking—Rheological Features
Agronomy 2021, 11(12), 2588; https://doi.org/10.3390/agronomy11122588 - 19 Dec 2021
Cited by 2 | Viewed by 885
Abstract
Improving the alpha-amylase activity of wheat flour represents an opportunity to valorize wheat grains of low baking quality. In this sense, germinated legumes can be used to increase enzymatic activity, giving superior final product characteristics at the same time. The aim of this [...] Read more.
Improving the alpha-amylase activity of wheat flour represents an opportunity to valorize wheat grains of low baking quality. In this sense, germinated legumes can be used to increase enzymatic activity, giving superior final product characteristics at the same time. The aim of this study was to underline the effects of chickpea (CGF) and lupin germinated flours (LGF) added simultaneously to white wheat flour on the rheological behavior of dough and to evaluate an optimal product microstructure. For this purpose, the falling number, dough rheological properties during mixing, 3D-deformation and fermentation, and the visco-elastic behavior were evaluated, the effects of factors (CGF and LGF levels) and their optimization have been studied by applying a full factorial design and response surface methodology (RSM). The LGF sample had a composition of 39.4% protein, 10.3% moisture, 6.9% fat, and 3.4% ash, whereas the CGF presented 21.1 % protein, 9.4% moisture, 5.2% fat, and 3.6% ash. The results showed that CGF and LGF determined the decrease of the falling number, dough water absorption, tolerance to kneading, dough consistency at 250 and 450 s, extensibility, the maximum height of the gas release curve, volume of gas retained by the dough at the end of the test, total volume of CO2 production, visco-elastic moduli, and gelatinization temperatures. On the other hand, dough elasticity and alveograph curve ratio increased proportionally to the increase of CGF and LGF addition levels. The optimal combination considering the rheological properties of dough was found to be 8.57% CGF, 5.31% LGF, and 86.12% wheat flour, with enhanced alpha-amylase activity being obtained compared to the control. These results provide valuable information on the possibility of using germinated legumes such as chickpeas and lupin in breadmaking to enhance wheat flour technological properties (besides traditionally used barley malt flour). Full article
(This article belongs to the Special Issue Agricultural Products: Nutritional Value and Functional Properties)
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Communication
Daisychain: Search and Interactive Visualisation of Homologs in Genome Assemblies
Agronomy 2021, 11(12), 2587; https://doi.org/10.3390/agronomy11122587 - 19 Dec 2021
Viewed by 745
Abstract
Daisychain is an interactive graph visualisation and search tool for custom-built gene homology databases. The main goal of Daisychain is to allow researchers working with specific genes to identify homologs in other annotation releases. The gene-centric representation includes local gene neighborhood to distinguish [...] Read more.
Daisychain is an interactive graph visualisation and search tool for custom-built gene homology databases. The main goal of Daisychain is to allow researchers working with specific genes to identify homologs in other annotation releases. The gene-centric representation includes local gene neighborhood to distinguish orthologs and paralogs by local synteny. The software supports genome sequences in FASTA format and GFF3 formatted annotation files, and the process of building the homology database requires a minimum amount of user interaction. Daisychain includes an integrated web viewer that can be used for both data analysis and data publishing. The web interface extends KnetMaps.js and is based on JavaScript. Full article
(This article belongs to the Special Issue Insights from Genetic Bioinformatics of Crops)
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Article
Quality and Yield of Lettuce in an Open-Air Rooftop Hydroponic System
Agronomy 2021, 11(12), 2586; https://doi.org/10.3390/agronomy11122586 - 19 Dec 2021
Cited by 2 | Viewed by 807
Abstract
In this study, the yield and growth performance of lettuce in an open-air rooftop hydroponic system were investigated. Lettuce was grown in a closed recirculating nutrient film technique (NFT) unit using a standard nutrient solution (NS). Yield, fresh weight, and nutrient content in [...] Read more.
In this study, the yield and growth performance of lettuce in an open-air rooftop hydroponic system were investigated. Lettuce was grown in a closed recirculating nutrient film technique (NFT) unit using a standard nutrient solution (NS). Yield, fresh weight, and nutrient content in the leaf tissue of the harvested lettuce were measured. The results were compared with the results obtained in indoor hydroponic lettuce growth with artificial lightning. Despite strong winds during the growth period, 25% of the total lettuce heads weighed twice the marketable weight; however, 25% of the total lettuce heads were below the marketable weight. A more efficient nutrient uptake was indicated by the lettuces in the rooftop system compared with the uptake in the indoor system. Foliar analysis revealed a higher content of all nutrients in the leaves of rooftop hydroponic lettuce compared with indoor hydroponic lettuce. This study suggests that hydroponic rooftop-grown lettuce can be competitive with their indoor counterparts if the rooftop hydroponic system is protected from extreme weather conditions. Full article
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Article
Identification of Candidate Genes and Genomic Regions Associated with Adult Plant Resistance to Stripe Rust in Spring Wheat
Agronomy 2021, 11(12), 2585; https://doi.org/10.3390/agronomy11122585 - 19 Dec 2021
Cited by 1 | Viewed by 741
Abstract
Wheat stripe rust (caused by Puccinia striiformis f. sp. tritici) is a major disease that damages wheat plants and affects wheat yield all over the world. In recent years, stripe rust became a major problem that affects wheat yield in Egypt. [...] Read more.
Wheat stripe rust (caused by Puccinia striiformis f. sp. tritici) is a major disease that damages wheat plants and affects wheat yield all over the world. In recent years, stripe rust became a major problem that affects wheat yield in Egypt. New races appeared and caused breakdowns in the resistant genotypes. To improve resistance in the Egyptian genotypes, new sources of resistance are urgently needed. In the recent research, a set of 95 wheat genotypes collected from 19 countries, including Egypt, were evaluated for their resistance against the Egyptian race(s) of stripe rust under field conditions in the two growing seasons 2018/2019 and 2019/2020. A high genetic variation was found among the tested genotypes. Single marker analysis was conducted using a subset of 71 genotypes and 424 diversity array technology (DArT) markers, well distributed across the genome. Out of the tested markers, 13 stable markers were identified that were significantly associated with resistance in both years (p-value ≤ 0.05). By using the sequence of the DArT markers, the chromosomal position of the significant DArT markers was detected, and nearby gene models were identified. Two markers on chromosomes 5A and 5B were found to be located within gene models functionally annotated with disease resistance in plants. These two markers could be used in marker-assisted selection for stripe rust resistance under Egyptian conditions. Two German genotypes were carrying the targeted allele of all the significant DArT markers associated with stripe rust resistance and could be used to improve resistance under Egyptian conditions. Full article
(This article belongs to the Special Issue Cereal Disease Resistance Genes and Fungal Effectors)
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Article
Chromosome Doubling in Genetically Diverse Bilberry (Vaccinium myrtillus L.) Accessions and Evaluation of Tetraploids in Terms of Phenotype and Ability to Cross with Highbush Blueberry (V. corymbosum L.)
Agronomy 2021, 11(12), 2584; https://doi.org/10.3390/agronomy11122584 - 19 Dec 2021
Cited by 1 | Viewed by 832
Abstract
To expand the gene pool and introduce new traits to the tetraploid cultivars of Vaccinium corymbosum from wild diploid species V. myrtillus, it is necessary to double the chromosome number in diploid species in order to overcome a post zygotic crossing barrier [...] Read more.
To expand the gene pool and introduce new traits to the tetraploid cultivars of Vaccinium corymbosum from wild diploid species V. myrtillus, it is necessary to double the chromosome number in diploid species in order to overcome a post zygotic crossing barrier and a strong triploid block, existing within the genus Vaccinium. Five genetically diverse bilberry genotypes were selected from 21 accessions taken from the breeding collection of the National Institute of Horticultural Research (Skierniewice, Poland) for this study. The bilberry genotypes were derived from the Polish locations of Bolimów Landscape Park, Budy Grabskie and forest complex Zwierzyniec (Łódź Province), and habitats in Norway. The selection of genotypes was made based on the analysis of amplified fragment length polymorphism (AFLP-PCR). Analysis of the Jaccard similarity indexes and the UPGMA method revealed that the examined accessions formed two main groups on the dendrogram. The first group consisted of accessions from Norway, while the second group agglomerated Polish accessions. A further two classes were distinguished in the Polish group: the first included accessions from Budy Grabskie and the second from Zwierzyniec, located ca. 9 km from Budy Grabskie. In order to obtain plant material for in vitro polyploidisation, in vitro shoot cultures of the selected accessions were initiated and multiplied. Both antimitotics used, colchicine and APM, induced tetraploids for all of the accessions. The obtained tetraploids were multiplied, rooted ex vitro and grown in a greenhouse and then in a field. The first flowering was observed in 1.5-year-old plants, either diploid or tetraploid. Diploids bloomed slightly earlier and more profusely than tetraploid plants. Compared to diploids, autotetraploids had significantly larger flowers by ca. 64% and larger pollen tetrads by ca. 35%. The germination capacity of pollen tetrads was high in tetraploids (87.8%), although slightly lower than in diploids (94.3%). After pollinating the flowers of three highbush blueberry cultivars with pollen from the bilberry tetraploid accession, J-4-4x, the plants formed fruits, some of which contained properly formed seeds. The effectiveness of interspecific crossing between V. corymbosum and tetraploid V. myrtillus, defined as the percentage of obtained seedlings in relation to the number of pollinated flowers, was highest (53.3%) in the blueberry ‘Liberty’, and lower in ‘Bluecrop’ and ‘Northland’, 14.8% and 10.0%, respectively. Before using the seedlings for further breeding, their hybridity will be confirmed by molecular markers and the phenotype will be evaluated. Full article
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Article
Evaluation of Crossability between Nicotiana benthamiana and Nicotiana excelsior
Agronomy 2021, 11(12), 2583; https://doi.org/10.3390/agronomy11122583 - 19 Dec 2021
Viewed by 746
Abstract
Wild tobacco species in the Nicotiana section Suaveolentes are promising genetic resources to introduce their disease resistance to cultivated tobacco, Nicotiana tabacum. However, hybrid lethality is observed in hybrid seedlings from crosses between most Suaveolentes species and N. tabacum. In particular, [...] Read more.
Wild tobacco species in the Nicotiana section Suaveolentes are promising genetic resources to introduce their disease resistance to cultivated tobacco, Nicotiana tabacum. However, hybrid lethality is observed in hybrid seedlings from crosses between most Suaveolentes species and N. tabacum. In particular, N. benthamiana belonging to the section Suaveolentes produces only viable hybrids after crossing with N. tabacum. In the present study, crossability between N. benthamiana and N. excelsior (section Suaveolentes) was investigated to test the possible usefulness of N. benthamiana as the bridge parent to transfer desirable genes of N. excelsior to N. tabacum via bridge crossing. After reciprocal crosses using three accessions of N. benthamiana and N. excelsior each, several crossing barriers such as cross-incompatibility, seed abortion, and male and female hybrid sterility were observed. Although reciprocal hybrids between N. benthamiana and N. excelsior showed a high degree of chromosome pairing in meiosis, univalents and multivalents, as well as chromosome bridges and lagging chromosomes, were observed. These meiotic abnormalities were thought to cause hybrid sterility. The possible usefulness of reciprocal hybrids between N. benthamiana and N. excelsior is discussed. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Effect of Soil-Applied L-tryptophan on the Amount of Biomass and Nitrogen and Sulfur Utilization by Maize
Agronomy 2021, 11(12), 2582; https://doi.org/10.3390/agronomy11122582 - 19 Dec 2021
Cited by 2 | Viewed by 685
Abstract
As natural plant growth stimulators, amino acids are widely used to improve crop yield and quality. There are numerous studies documenting the influence of amino acids on plants, which is not always positive. This study was conducted to determine the effect of soil-applied [...] Read more.
As natural plant growth stimulators, amino acids are widely used to improve crop yield and quality. There are numerous studies documenting the influence of amino acids on plants, which is not always positive. This study was conducted to determine the effect of soil-applied L-tryptophan (L-TRP) on the accumulation and utilization of nitrogen and sulfur by maize. The study was carried out under the conditions of a pot experiment. The experimental design included three treatments: soil without fertilization (control), soil with mineral fertilization (NPKS), and soil with mineral fertilization and L-tryptophan addition (NPKS + L-TRP). The application of tryptophan to the soil, supported by mineral fertilization, caused a significant increase in maize biomass. Although no significant differences in nitrogen and sulfur contents in maize biomass were found between treatments without and with the addition of L-tryptophan, significantly higher intakes of both elements were observed in the NPKS + L-TRP treatment. The application of L-tryptophan increased the biosynthesis of Chlorophyll a. Utilization of nitrogen and sulfur by maize in the NPKS + L-TRP treatment was more than 27% and 17% higher, respectively, compared to the NPKS treatment. Maintaining the recommended contents of individual nutrients in the rhizosphere is not a guarantee of optimal quantitative and qualitative intake of nutrients. Problems with maintaining optimal relationships between individual nutrients may be compounded by soil properties. Full article
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Article
Selection of Elite dura-Type Parents to Produce Dwarf Progenies of Elaeis guineensis Using Genetic Parameters
Agronomy 2021, 11(12), 2581; https://doi.org/10.3390/agronomy11122581 - 18 Dec 2021
Cited by 1 | Viewed by 744
Abstract
The low annual growth rate of the stipe in oil palm progenies is desirable to increase these crops’ productive and economic life. Recurrent reciprocal selection (R.R.S.) has allowed the development of oil palm populations through several breeding cycles with an increased frequency of [...] Read more.
The low annual growth rate of the stipe in oil palm progenies is desirable to increase these crops’ productive and economic life. Recurrent reciprocal selection (R.R.S.) has allowed the development of oil palm populations through several breeding cycles with an increased frequency of favorable alleles associated with traits of interest. The present study evaluated families derived from Deli dura × African dura crosses. For 12 years, the yield, vegetative characteristics, and the amount of oil in seven dura progenies were assessed to estimate, from the information collected, the genetic parameters, heritability, and phenotypic correlations among quantitative genetic traits of high-yielding dwarf progenies. The analysis was carried out using analysis of variance, followed by a comparison of means for all estimated traits. The effect of the progenies was highly significant (p ≤ 0.01) for most traits. The yield values, expressed in fresh fruit bunches (FFB) for the progenies, ranged from 165 to 208 kg per palm per year. The oil-to-bunch ratio (O/B) ranged from 17% to 19%, with an overall average of 18%. One of the essential characteristics in this study was the vertical growth of the stipe. Progenies P6 and P7 were identified as those with the lowest annual increase in height, with values of 0.29 and 0.33 m year−1. The values indicate that these are slow-growing cultivars with a high FFB yield and O/B. The highest heritabilities were found for the vegetative trait height (71.62%) and the number of leaflets (46.64%). The development of dura parents with slow growth characteristics in combination with a high bunch and oil production allows extending the productive life of the crop to more than 35 years, providing added value to obtaining differentiated cultivars of oil palm. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Review
Ecological Intensification of Food Production by Integrating Forages
Agronomy 2021, 11(12), 2580; https://doi.org/10.3390/agronomy11122580 - 18 Dec 2021
Cited by 1 | Viewed by 1138
Abstract
Forage crops have the potential to serve multiple functions, providing an ecological framework to sustainably intensify food production, i.e., ecological intensification. We review three categories of forages (annual forages, perennial forages, and dual-use perennial crops/forages) we believe hold the greatest promise for ecologically [...] Read more.
Forage crops have the potential to serve multiple functions, providing an ecological framework to sustainably intensify food production, i.e., ecological intensification. We review three categories of forages (annual forages, perennial forages, and dual-use perennial crops/forages) we believe hold the greatest promise for ecologically intensifying food production. Annual cover crops can provide additional forage resources while mitigating nutrient losses from agricultural fields when they are intercropped with, interseeded into, or following an annual crop, for instance. The integration of perennial forages either temporally, such as annual crop rotations that include a perennial forage phase, or spatially, such as the intercropping of perennial forages with an annual cash crop, provide weed suppression, soil quality, and yield and crop quality benefits. Dual-use crops/forages can provide forage and a grain crop in a single year while providing multiple ecological and economic benefits. However, tradeoffs in balancing multiple functions and limitations in reducing the risks associated with these practices exist. Advancing our understanding of these systems so we can overcome some of the limitations will play a critical role in increasing food production while promoting positive environmental outcomes. Full article
(This article belongs to the Special Issue Multifunctional Forages)
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Article
Chili and Sweet Pepper Seed Oil Used as a Natural Antioxidant to Improve the Thermo-Oxidative Stability of Sunflower Oil
Agronomy 2021, 11(12), 2579; https://doi.org/10.3390/agronomy11122579 - 18 Dec 2021
Cited by 2 | Viewed by 724
Abstract
The main purpose of this work was to assess the potential of chili pepper seed oil (CPSO) and sweet pepper seed oil (SPSO) to inhibit or retard the thermo-oxidative processes undergoing in sunflower oil (SFO) when subjected to high-temperature heating for 4 and [...] Read more.
The main purpose of this work was to assess the potential of chili pepper seed oil (CPSO) and sweet pepper seed oil (SPSO) to inhibit or retard the thermo-oxidative processes undergoing in sunflower oil (SFO) when subjected to high-temperature heating for 4 and 8 h in simulated frying conditions. The effects of high-temperature treatment for 4 and 8 h on the fatty acid composition and the lipid oxidation degree of the investigated oil samples were evaluated using the peroxide value (PV), the p-anisidine value (p-AV) and the thiobarbituric acid test (TBA). All determinations were performed before and after sample heating in order to evaluate the changes in lipid oxidation as well as in the chemical composition. In all studied samples, both after 4 h and 8 h of high-temperature heating, there was an increase of the saturated fatty acid content. This increase is lower in the case of SFO samples supplemented with CPSO and SPSO when compared with SFO. A 41.67% increase was recorded for the SFO sample supplemented with 300 ppm CPSO, and a 36.76% increase was recorded for the SFO supplemented with 300 ppm SPSO, compared to the 44.97% increase recorded for the SFO. Heating the samples supplemented with CPSO and SPSO with a concentration of 300 ppm for 8 h led to the much lower values of the investigated parameters in relation to the control sample, as follows: PV (12.95 ± 0.17 meq/kg oil for SFO + 300 ppm CPSO and 13.45 ± 0.32 meq/kg oil for SFO + 300 ppm SPSO, compared with 16.4 + 0.17 meq/kg oil for SFO), p-AV (63.445 ± 1.259 ppm oil for SFO + 300 ppm CPSO and 64.122 ± 1.208 ppm oil for SFO + 300 ppm SPSO, compared with 72.493 + 1.340 ppm oil for SFO), CD (45%; 30%), TOTOX (88.374 for SFO + 300 ppm CPSO and 101.366 for SFO + 300 ppm SPSO compared with 105.347 ppm for SFO) and TBA (98.92 ± 2.49 µg MDA/g oil for SFO + 300 ppm CPSO and 114.24 ± 3.51 µg MDA/g oil for SFO + 300 ppm SPSO, compared with 180.08 + 5.82 µg MDA/g oil for SFO). Regarding the lipid oxidation process occurring during the heat treatment, we observed the reduction of lipid oxidation by the addition of CPSO and SPSO and recommend these seed oils as potential natural antioxidants in order to improve the oxidative stability of SFO during heat treatment. Full article
(This article belongs to the Special Issue Agricultural Products: Nutritional Value and Functional Properties)
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Article
Mapping Gaps in Sugarcane by UAV RGB Imagery: The Lower and Earlier the Flight, the More Accurate
Agronomy 2021, 11(12), 2578; https://doi.org/10.3390/agronomy11122578 - 18 Dec 2021
Cited by 3 | Viewed by 1282
Abstract
Imagery data prove useful for mapping gaps in sugarcane. However, if the quality of data is poor or the moment of flying an aerial platform is not compatible to phenology, prediction becomes rather inaccurate. Therefore, we analyzed how the combination of pixel size [...] Read more.
Imagery data prove useful for mapping gaps in sugarcane. However, if the quality of data is poor or the moment of flying an aerial platform is not compatible to phenology, prediction becomes rather inaccurate. Therefore, we analyzed how the combination of pixel size (3.5, 6.0 and 8.2 cm) and height of plant (0.5, 0.9, 1.0, 1.2 and 1.7 m) could impact the mapping of gaps on unmanned aerial vehicle (UAV) RGB imagery. Both factors significantly influenced mapping. The larger the pixel or plant, the less accurate the prediction. Error was more likely to occur for regions on the field where actively growing vegetation overlapped at gaps of 0.5 m. Hence, even 3.5 cm pixel did not capture them. Overall, pixels of 3.5 cm and plants of 0.5 m outstripped other combinations, making it the most accurate (absolute error ~0.015 m) solution for remote mapping on the field. Our insights are timely and provide forward knowledge that is particularly relevant to progress in the field’s prominence of flying a UAV to map gaps. They will enable producers to make decisions on replanting and fertilizing site-specific high-resolution imagery data. Full article
(This article belongs to the Special Issue Imaging Technology for Detecting Crops and Agricultural Products)
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Article
Multicolor Fluorescence Imaging for the Early Detection of Salt Stress in Arabidopsis
Agronomy 2021, 11(12), 2577; https://doi.org/10.3390/agronomy11122577 - 18 Dec 2021
Viewed by 616
Abstract
Salt stress is one of the abiotic factors that causes adverse effects in plants and there is an urgent need to detect salt stress in plants as early as possible. Multicolor fluorescence imaging, as a powerful tool in plant phenotyping, can provide information [...] Read more.
Salt stress is one of the abiotic factors that causes adverse effects in plants and there is an urgent need to detect salt stress in plants as early as possible. Multicolor fluorescence imaging, as a powerful tool in plant phenotyping, can provide information about primary and secondary metabolism in plants to detect the responses of the plants exposed to stress in the early stage. The purpose of this study was to evaluate the potential of multicolor fluorescence imaging’s application in the early detection of salt stress in plants. In this study, the measurements were conducted on Arabidopsis and the multicolor fluorescence images were acquired at 440, 520, 690, and 740 nm with a self-developed imaging system consisting of a UV light-emitting diode (LED) panel for an excitation at 365 nm, a charge coupled device (CCD) camera, interference filters, and a computer. We developed a classification method using the imaging analysis of multicolor fluorescence based on principal component analysis (PCA) and a support vector machine (SVM). The results showed that the four principal fluorescence feature combinations were the ideal indicators as the inputs of the SVM model, and the classification accuracies of the control and salt-stress treatment at 5 days and 9 days were 92.65% and 98.53%, respectively. The results indicated that multicolor fluorescence imaging combined with PCA and SVM could act as a tool for early detection in salt-stressed plants. Full article
(This article belongs to the Section Agricultural Biosystem and Biological Engineering)
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Article
Farm-Scale Crop Yield Prediction from Multi-Temporal Data Using Deep Hybrid Neural Networks
Agronomy 2021, 11(12), 2576; https://doi.org/10.3390/agronomy11122576 - 18 Dec 2021
Cited by 4 | Viewed by 1163
Abstract
Farm-scale crop yield prediction is a natural development of sustainable agriculture, producing a rich amount of food without depleting and polluting environmental resources. Recent studies on crop yield production are limited to regional-scale predictions. The regional-scale crop yield predictions usually face challenges in [...] Read more.
Farm-scale crop yield prediction is a natural development of sustainable agriculture, producing a rich amount of food without depleting and polluting environmental resources. Recent studies on crop yield production are limited to regional-scale predictions. The regional-scale crop yield predictions usually face challenges in capturing local yield variations based on farm management decisions and the condition of the field. For this research, we identified the need to create a large and reusable farm-scale crop yield production dataset, which could provide precise farm-scale ground-truth prediction targets. Therefore, we utilise multi-temporal data, such as Sentinel-2 satellite images, weather data, farm data, grain delivery data, and cadastre-specific data. We introduce a deep hybrid neural network model to train this multi-temporal data. This model combines the features of convolutional layers and recurrent neural networks to predict farm-scale crop yield production across Norway. The proposed model could efficiently make the target predictions with the mean absolute error of 76 kg per 1000 m2. In conclusion, the reusable farm-scale multi-temporal crop yield dataset and the proposed novel model could meet the actual requirements for the prediction targets in this paper, providing further valuable insights for the research community. Full article
(This article belongs to the Section Crop Breeding and Genetics)
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Article
Assessment of the Interactive Effect of the Use of 1-Methylcyclopropene and Cultivars on the Nutritional Value of Broccoli during Storage
Agronomy 2021, 11(12), 2575; https://doi.org/10.3390/agronomy11122575 - 17 Dec 2021
Viewed by 694
Abstract
Broccoli is a short-term fresh storage vegetable; it most often goes to the processing plant where it is frozen or cold-stored. 1-methylcyclopropene gas (1-MCP) can be used to extend broccoli’s shelf life. The aim of the study was to investigate the effect of [...] Read more.
Broccoli is a short-term fresh storage vegetable; it most often goes to the processing plant where it is frozen or cold-stored. 1-methylcyclopropene gas (1-MCP) can be used to extend broccoli’s shelf life. The aim of the study was to investigate the effect of the genetic cultivar determinants, the use of 1-MCP and the storage time on the weight loss as well as the content of nutrients and harmful compounds in cultivars: ‘Bay Meadows’, ‘Monaco’, ‘Naxos’ and ‘Vicario’. The cultivars selected for the study differed significantly in terms of the traits after harvest and storage, and the differences were also conditioned by the interaction of the genetic factor and 1-MCP used, especially within 30 days after harvest. Of the broccoli cultivars, ‘Monaco’ demonstrated the lowest weight loss during storage, the highest content of dry weight, total sugars, vitamin C, both after harvest and after storage, in the samples treated with 1-methylcycloprepene after harvest. In turn, ‘Vicario’ lost most weight after storage and broccoli florets treated with 1-MCP have lost less weight. The highest amounts of nitrates and nitrites, both after harvest and after storage, were found in ‘Monaco’; however, the differences, as compared with the other cultivars, were significant, yet relatively low. The lowest compactness of the florets was recorded, and hence the lowest commercial value (basically unmarketable), for ‘Naxos’, ‘Monaco’ and ‘Vicario’ cultivars after 30 days of storage without the use of 1-MCP. However, due to the use of 1-MCP and low temperature (4 °C), the commercial value of those broccoli cultivars was satisfactory. Full article
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Review
Polyploidy in Industrial Crops: Applications and Perspectives in Plant Breeding
Agronomy 2021, 11(12), 2574; https://doi.org/10.3390/agronomy11122574 - 17 Dec 2021
Cited by 4 | Viewed by 1152
Abstract
Polyploidisation is an important process in the evolution of many plant species. An additional set of chromosomes can be derived from intraspecific genome duplication (autopolyploidy) or hybridising divergent genomes and chromosome doubling (allopolyploidy). Special forms of polyploidy are autoallopolyploidy and segmental allopolyploidy. Polyploidy [...] Read more.
Polyploidisation is an important process in the evolution of many plant species. An additional set of chromosomes can be derived from intraspecific genome duplication (autopolyploidy) or hybridising divergent genomes and chromosome doubling (allopolyploidy). Special forms of polyploidy are autoallopolyploidy and segmental allopolyploidy. Polyploidy arises from two basic processes: spontaneously occurring disturbances of meiotic division and induced by antimitotic agents’ disruption of mitosis. The first involves the induction and fusion of unreduced gametes, resulting in the formation of triploids and tetraploids. The second process uses antimitotics that disrupt cellular microtubules and prevent chromosome’s sister chromatids motion during anaphase. Colchicine, oryzalin, and trifluralin are the most commonly used antimitotics for inducing polyploids in plants. The exposure time and concentration of the antimitotics and the species, cultivar, genotype, and tissue type affect the efficiency of genome duplication. Polyploids are distinguished from diploids by increased cell size and vegetative parts of plants and increased content of secondary metabolites. Genome duplication generates several changes at the epigenetic level resulting in altered gene expression. Polyploidisation is used in plant breeding to overcome the non-viability and infertility of interspecific hybrids, obtain seedless polyploid cultivars and increase resistance/tolerance to biotic and abiotic factors. Full article
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Article
Potassium-Induced Drought Tolerance of Potato by Improving Morpho-Physiological and Biochemical Attributes
Agronomy 2021, 11(12), 2573; https://doi.org/10.3390/agronomy11122573 - 17 Dec 2021
Cited by 5 | Viewed by 1008
Abstract
Potato (Solanum tuberosum) is the third and fourth most important tuberous crop in terms of human consumption and production, respectively. However, its growth and development are affected by drought, which is an emerging threat to agriculture especially in arid and semiarid [...] Read more.
Potato (Solanum tuberosum) is the third and fourth most important tuberous crop in terms of human consumption and production, respectively. However, its growth and development are affected by drought, which is an emerging threat to agriculture especially in arid and semiarid areas. Potassium (K) is a well-known macronutrient that improves the performance of crops under drought. Therefore, the present study was enacted with the aim of evaluating the impact of K fertilizer on potato crop growth, productivity, and drought tolerance under full root irrigation (FRI) and partial root irrigation (PRI) conditions. Two potato cultivars (Lady Rosetta and Hermes) were grown under normal field conditions followed by FRI and PRI applications. Potassium sulfate was applied in three doses (T0 = 50 kg·ha−1, T1 = 75 kg·ha−1, and T2 = 100 kg·ha−1). The experiment was laid out under randomized complete block design (RCBD) with split plot arrangement. The main plot was allocated to irrigation, along with a subplot to potassium and a sub-subplot to potato cultivars. The results indicated that K application significantly improved the plant growth and yield by exhibiting better performance in morpho-physiological and biochemical attributes under FRI and PRI conditions; however, a more remarkable change was noticed under PRI compared with FRI. K application alleviated drought stress regardless of cultivars. This study suggests that K application at the rate of 100 kg·ha−1 is an effective approach for inducing drought tolerance in potato crops. Full article
(This article belongs to the Special Issue Molecular Genetic Improvement of Crop Drought Tolerance)
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Article
Effects of Nitrogen Rates on the Productivity and Nutritive Value of Forage Grass Grown under Extreme Climatic Conditions
Agronomy 2021, 11(12), 2572; https://doi.org/10.3390/agronomy11122572 - 17 Dec 2021
Viewed by 659
Abstract
This vegetative experiment was carried out at the greenhouse of Vytautas Magnus University Agriculture Academy Open Access Joint Research Centre of Agriculture and Forestry (Lithuania) in 2020–2021. The aim of these studies was to determine the effect of different nitrogen rates on the [...] Read more.
This vegetative experiment was carried out at the greenhouse of Vytautas Magnus University Agriculture Academy Open Access Joint Research Centre of Agriculture and Forestry (Lithuania) in 2020–2021. The aim of these studies was to determine the effect of different nitrogen rates on the productivity and nutritional quality of forage grasses (a mixture of red clover and timothy) under the most common extremes of climate change, i.e., soil moisture deficiency and surplus. Under drought and waterlogging stresses, fertilization of the red clover and timothy mixture with high N rates was ineffective. The clover and timothy mixture recovery after drought took 21 days. The aboveground dry biomass of the clover and timothy mixture grown under drought conditions was significantly lower by 36.3 to 47.2% compared to that formed under optimum soil moisture and waterlogging conditions. The root biomass of forage grass mixtures was lowest under drought conditions when fertilized at the highest N rate (N25+120). The aboveground biomass of clover grown under different soil moisture conditions depended on the number of plants (r2 = 0.78, p < 0.01) and assimilating leaf area (r2 = 0.83, p < 0.01), and that of timothy on the number of vegetative tillers (r2 = 0.46, p < 0.05). Under drought simulation conditions, increasing the N rate increased the crude protein and crude fibre contents in the aboveground biomass of the clover and timothy mixture, while the crude ash content decreased. Full article
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Article
The Effect of Microwave Treatment on Germination and Health of Carrot (Daucus carota L.) Seeds
Agronomy 2021, 11(12), 2571; https://doi.org/10.3390/agronomy11122571 - 17 Dec 2021
Viewed by 637
Abstract
The aim of the study was to evaluate the effect of microwave treatment on seed germination and health of carrot seeds using two seed lots naturally infected with the pathogens Alternaria dauci and A. radicina. Seeds of cv. Amsterdam and cv. Berlikumer [...] Read more.
The aim of the study was to evaluate the effect of microwave treatment on seed germination and health of carrot seeds using two seed lots naturally infected with the pathogens Alternaria dauci and A. radicina. Seeds of cv. Amsterdam and cv. Berlikumer varied in seed germination at the final count (50% and 29%, respectively), and seed infestation with A. radicina (38% and 5%, respectively). For treatment, seeds were placed in a Petri dish (dry treatment) or in a beaker with distilled water (wet treatment) and irradiated at power output levels 500, 650 and 750 W for 15, 30, 45, 60, 75, and 90 s. Germination and health were determined in treated and untreated (control) seed samples. Wet treatment controlled seed-borne fungi more efficiently than dry treatment. However, the exposure duration longer than 60 s frequently resulted in deterioration of seed germination. The highest seed germination in cv. Amsterdam was observed after microwave wet treatment at power output levels of 500 W for 75 s (81%), 650 W for 45 s (85%), and 750 W for 60 s (77%), whereas in the case of cv. Berlikumer this occurred when wet seeds were treated at 500 and 650 W for 60 s (46% and 43% respectively). Treating seeds soaked in water with microwaves for a period longer than 30 s, regardless of the power output, significantly decreased seed infestation with Alternaria spp. in both samples. Full article
Article
Energy Efficient Lighting in Plant Factories: Addressing Utilance
Agronomy 2021, 11(12), 2570; https://doi.org/10.3390/agronomy11122570 - 17 Dec 2021
Viewed by 773
Abstract
Vertical farming is considered to play a crucial role in future food supply. Until today, the high amount of electrical energy required for artificial lighting has been problematic in this context. Various possibilities for increasing efficiency through adapted lighting conditions have been and [...] Read more.
Vertical farming is considered to play a crucial role in future food supply. Until today, the high amount of electrical energy required for artificial lighting has been problematic in this context. Various possibilities for increasing efficiency through adapted lighting conditions have been and are being investigated. However, comparably little attention is paid to increasing utilance, i.e., the amount of photons that can effectively be used by the plant. In this work, a novel targeted lighting strategy is therefore proposed that allows for a dynamic adaptation of the luminaires’ light distribution to match the effective crop size at each stage of plant growth in a fully-automated manner. It is shown that the resulting utilance can significantly be increased compared to standard full-coverage lighting. Moreover, it is found that the proposed strategy is likely to consume less than half of the electrical energy usually required for the latter. An additional increase in system efficiency can be prognosticated and the potential energy savings are estimated based on assumptions of future LED generations derived from literature. Full article
(This article belongs to the Special Issue New Technologies to Enable a Sustainable Vertical Farming Industry)
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Article
The Perfect Match: Adjusting High Tree Density to Rootstock Vigor for Improving Cropping and Land Use Efficiency of Sweet Orange
Agronomy 2021, 11(12), 2569; https://doi.org/10.3390/agronomy11122569 - 17 Dec 2021
Cited by 1 | Viewed by 709
Abstract
The rise in the productivity of sweet orange in Brazil has been related to the use of superior rootstocks and higher tree density, among other factors. In order to investigate whether the cropping system and the land use efficiency would benefit from more [...] Read more.
The rise in the productivity of sweet orange in Brazil has been related to the use of superior rootstocks and higher tree density, among other factors. In order to investigate whether the cropping system and the land use efficiency would benefit from more intensive cultivation, the performance of Valencia sweet orange was evaluated over nine years on four rootstocks, which induced contrasting vigor, at 513, 696 and 1000 trees·ha−1. Agronomic Institute of Campinas (IAC) 1697 and IAC 1710 citrandarins, and diploid and allotetraploid (4×) Swingle citrumelos were classified as semi-dwarfing, super-standard, standard, and dwarfing rootstocks, respectively. The fruit yield per tree was decreased at higher tree densities, notably for more vigorous rootstocks. Conversely, the cumulative productivity was increased over the evaluation period by 27% at 1000 trees·ha−1, irrespective of the rootstock, and the most vigorous rootstock resulted in 2.5 times higher production than the dwarfing one on average. Most fruit quality parameters were seldom influenced by the tree density, while the rootstock was a decisive factor in improving the quality and the soluble solids content. Dwarfing rootstocks allowed for harvesting 17% more fruit per minute by manual pickers. Because the tree row volume per area is lower with such rootstocks, even at higher tree density, spray volume can be reduced, although appropriate equipment should be developed for better spray coverage on smaller trees. Nine years after planting under strict vector control, the cumulative incidence of huanglongbing-symptomatic trees on IAC 1710 was double that on Swingle 4×. Taken together, the results suggested that the land use efficiency in the citrus industry can be further improved by planting vigorous rootstocks at moderate to high tree densities. Nevertheless, obtaining highly productive semi-dwarfing and dwarfing rootstocks is the sine qua non for making high-density pedestrian sweet orange orchards more profitable. Full article
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Editorial
Sprouts, Microgreens and Edible Flowers as Novel Functional Foods
Agronomy 2021, 11(12), 2568; https://doi.org/10.3390/agronomy11122568 - 17 Dec 2021
Cited by 3 | Viewed by 733
Abstract
Nowadays, interest in novel functional foods has been on the rise, compelled by the increased interest of the consumers, researchers, food nutritionists, producers, and extension specialists for diets able to maintain health and preventing chronic diseases by providing essential nutrients, phytochemicals, and calories [...] Read more.
Nowadays, interest in novel functional foods has been on the rise, compelled by the increased interest of the consumers, researchers, food nutritionists, producers, and extension specialists for diets able to maintain health and preventing chronic diseases by providing essential nutrients, phytochemicals, and calories for the body metabolism [...] Full article
(This article belongs to the Special Issue Sprouts, Microgreens and Edible Flowers as Novel Functional Foods)
Article
Robotic Mowing of Tall Fescue at 90 mm Cutting Height: Random Trajectories vs. Systematic Trajectories
Agronomy 2021, 11(12), 2567; https://doi.org/10.3390/agronomy11122567 - 17 Dec 2021
Cited by 2 | Viewed by 683
Abstract
Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is often managed with a cutting height ranging from 70 to 100 mm in ornamental lawns. Some autonomous mowers have been specifically designed to maintain mowing height in the same range. Generally, autonomous mowers operate by [...] Read more.
Tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) is often managed with a cutting height ranging from 70 to 100 mm in ornamental lawns. Some autonomous mowers have been specifically designed to maintain mowing height in the same range. Generally, autonomous mowers operate by following random trajectories, and substantial overlapping is needed to obtain full coverage of the working area. In the case of tall grass, this may cause lodging of grass plants, which in turn may reduce turf quality. The introduction of a navigation system based on systematic trajectories has the potential to improve the performances of autonomous mowers with respect to machine efficiency and turf quality. With the aim of determining the effects of reduced mowing frequency and systematic navigation systems on turf quality and mower performances in terms of working time, energy consumption and overlapping, the performances of two autonomous mowers working with random and systematic trajectories were tested on a mature tall fescue lawn at 90 mm cutting height. The working efficiency was approximately 80% for the systematic trajectories and approximately 35% for the random trajectories; this was mainly due to the lower overlapping associated with systematic trajectories. Turf quality was slightly higher for the mower working systematically (a score of 8 using a 1–9 score with 1 = poor, 6 = acceptable and 9 = best) compared to the one working randomly (quality of 7 and 6 on a 1–9 scale with 1 = poor and 9 = best). No appreciable lodging was observed in either case. For tall, managed lawns, systematic trajectories may improve autonomous mowers’ overall performances. Full article
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