Agronomy

14 pages, 3131 KiB

Open AccessArticle

Performance of Different Bunch Cover Materials to Improve Quality of Cavendish Banana Cultivated during Winter and Summer in Thailand

by Saowapa Chaiwong, Rattapon Saengrayap, Johnson Makinwa Ogunsua, Hiroaki Kitazawa and Chureerat Prahsarn

Agronomy 2021, 11(3), 610; https://doi.org/10.3390/agronomy11030610 - 23 Mar 2021

Cited by 5 | Viewed by 4267

Abstract

Performance of different cover materials on improving Cavendish banana quality was examined during winter and summer. The banana bunch was covered with a thin nonwoven innermost layer, followed by cover materials arranged from inner to outer as follows. (1) Control (commercial cover), paper/polystyrene [...] Read more.

Performance of different cover materials on improving Cavendish banana quality was examined during winter and summer. The banana bunch was covered with a thin nonwoven innermost layer, followed by cover materials arranged from inner to outer as follows. (1) Control (commercial cover), paper/polystyrene sheet (PS)/non-perforated blue polyethylene (NPPE), (2) nonwoven (NW)/NPPE, (3) waterproof nonwoven (WPNW), (4) aluminum foil (ALF), and (5) WPNW + ALF. For the summer trial, control without PS layer was applied. Material properties including thickness, light transmissivity and heat energy (Q_x) were evaluated. Results showed that Q_x values transferred through PS sheet, NW, WPNW and ALF were not significantly different. ALF exhibited the lowest light transmissivity, associated with the highest fruit lightness (L*) and lowest fruit weight. For the winter trial, all cover materials exhibited chilling injury on fruit caused by temperatures below 10 °C. For the summer trial, five treatments prevented sunburn defect. Under field air temperature of 47.5 °C, ALF exhibited the lowest temperature (31.6 °C). All cover materials reduced hand and fruit sizes, whereas WPNW resulted in an increase in total soluble solids and prevented fading of the green peel color. Results suggested that WPNW, with reduced layers as environmentally friendly and reusable materials, had potential as a cover material to improve the quality of Cavendish banana. Full article

(This article belongs to the Special Issue Innovative Technologies for Conservation, Protection, and Quality of Vegetables and Fruits in a Postharvest Period)

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14 pages, 692 KiB

Open AccessArticle

Comparative Evaluation of Tomato Hybrids and Inbred Lines for Fruit Quality Traits

by Ilias D. Avdikos, Rafail Tagiakas, Pavlos Tsouvaltzis, Ioannis Mylonas, Ioannis N. Xynias and Athanasios G. Mavromatis

Agronomy 2021, 11(3), 609; https://doi.org/10.3390/agronomy11030609 - 23 Mar 2021

Cited by 6 | Viewed by 4202

Abstract

Tomato is one of the most consumed fruit vegetables globally and is a high dietary source of minerals, fiber, carotenoids, and vitamin C. The tomato is also well known for its nutraceutical chemical content which strengthens human immune systems and is protective against [...] Read more.

Tomato is one of the most consumed fruit vegetables globally and is a high dietary source of minerals, fiber, carotenoids, and vitamin C. The tomato is also well known for its nutraceutical chemical content which strengthens human immune systems and is protective against infectious and degenerative diseases. For this reason, there has been recent emphasis on breeding new tomato cultivars with nutraceutical value. Most of the modern tomato cultivars are F₁ hybrids, and many of the characteristics associated with fruit quality have additive gene action; so, in theory, inbred vigor could reach hybrid vigor. A sum of 20 recombinant lines was released from the commercial single-cross hybrids Iron, Sahara, Formula, and Elpida, through a breeding process. Those recombinant lines were evaluated during spring–summer 2015 under organic farming conditions in a randomized complete block design (RCBD) experimental design with three replications. A sum of eleven qualitative characteristics of the fruit was recorded on an individual plant basis. Results from this study indicated that the simultaneous selection of individual tomato plants, both in terms of their high yield and desired fruit quality characteristics, can lead to highly productive recombinant lines with integrated quality characteristics. So, inbred vigor can reach and even surpass hybrid vigor. The response to selection for all characteristics evaluated shows additive gene action of all characteristics measured. These recombinant lines can fulfill this role as alternatives to hybrid cultivars and those that possess high nutritional values to function as functional-protective food. Full article

(This article belongs to the Special Issue Genetic Improvement of Vegetable Crops)

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11 pages, 1958 KiB

Open AccessArticle

Effect of a Biostimulant on Bermudagrass Fall Color Retention and Spring Green-Up

by Verónica De Luca and Diego Gómez de Barreda

Agronomy 2021, 11(3), 608; https://doi.org/10.3390/agronomy11030608 - 23 Mar 2021

Cited by 3 | Viewed by 2193

Abstract

Field research was conducted in 2017–2019 on “Princess 77” bermudagrass (Cynodon dactylon (L.) Pers.) to determine whether an amino acid based biostimulant program applied in the late season (October-November) and early season (March-April) could extend fall color retention (FCR) or hasten the [...] Read more.

Field research was conducted in 2017–2019 on “Princess 77” bermudagrass (Cynodon dactylon (L.) Pers.) to determine whether an amino acid based biostimulant program applied in the late season (October-November) and early season (March-April) could extend fall color retention (FCR) or hasten the spring green-up (SGU), respectively. Bermudagrass was treated with the biostimulant under five different managements: non-treated; 6 times at 5 L ha⁻¹ weekly; 3 times at 5 L ha⁻¹ in a 14-day interval; 6 times at 10 L ha⁻¹ weekly; and 3 times at 10 L ha⁻¹ in a 14-day interval. Normalized difference vegetation index (NDVI) and visual ratings (turf green color and percentage of green coverage in the subplot) were determined weekly, and turf clipping dry weight for the SGU studies. At the end of the FCR studies (2017 and 2018), there was no effect of the biostimulant; although, some isolated positive effects were detected during the experiment in 2017 on bermudagrass treated weekly at 10 L ha⁻¹ for NDVI. However, there was a slight positive effect on SGU when this physiological process occurred slowly (year 2018) and the biostimulant was applied weekly at 10 L ha⁻¹ (4.4 kg N ha⁻¹), compared to another performed management and warmer years (2017 and 2019). Full article

(This article belongs to the Special Issue Biostimulants and Micronutrients: Innovative Tools to Increase Crop Quality and Abiotic Stress Tolerance in Plants)

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28 pages, 2900 KiB

Open AccessArticle

Soil Water Retention and Soil Compaction Assessment in a Regional-Scale Strategy to Improve Climate Change Adaptation of Agriculture in Navarre, Spain

by Rodrigo Antón, Alberto Ruiz-Sagaseta, Luis Orcaray, Francisco Javier Arricibita, Alberto Enrique, Isabel de Soto and Iñigo Virto

Agronomy 2021, 11(3), 607; https://doi.org/10.3390/agronomy11030607 - 23 Mar 2021

Cited by 3 | Viewed by 3523

Abstract

The aim of this study was to evaluate the effectiveness of the different agricultural management adaptive strategies considered in the framework of a regional climate change adaptation roadmap in Navarre (Spain), from the point of view of soil physical indicators associated to soil [...] Read more.

The aim of this study was to evaluate the effectiveness of the different agricultural management adaptive strategies considered in the framework of a regional climate change adaptation roadmap in Navarre (Spain), from the point of view of soil physical indicators associated to soil compaction and water retention. These indicators were chosen as representative of the potential of these strategies to improve the soil physical condition. That for, the effectiveness of conservation agriculture (CA), crop rotations (ROT), additions of organic matter (ExO), irrigation (IRR) and innovative grassland management (GSS) was assessed by monitoring soil bulk density (BD) and soil available water holding capacity (AWHC) in a network of 159 agricultural fields across homogeneous agro-climatic zones in the region. A sampling protocol designed to compare groups of plots with or without adaptive practices, and with equal soil characteristics within each zone, allowed to determine the effect size of each strategy (measured as response ratios, RR, calculated as the relative value of BD and AWHC in fields with adaptive management vs. without). Both parameters responded to soil and crop management, although the observed effect was highly variable. Only the ExO strategy showed an overall positive effect on BD. ROT, IRR and GSS displayed no effect and, in the case of CA, the effect was negative. In terms of AWHC, although the results within the zones were heterogeneous, the overall effect associated to the strategies ROT, ExO, IRR and GSS was neutral, and only CA resulted in an overall negative effect. The observed variability in terms of the effectiveness of the five strategies tested in this region highlights the need to understand the complexity of interrelationships between management and dynamic soil properties at the regional scale. Full article

(This article belongs to the Special Issue Soil Degradation Prevention and Restoration at Farm and Field Scale)

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15 pages, 3230 KiB

Open AccessArticle

Strawberry Flavor Is Influenced by the Air Temperature Differential during Fruit Development but Not Management Practices

by Anya Osatuke and Marvin Pritts

Agronomy 2021, 11(3), 606; https://doi.org/10.3390/agronomy11030606 - 23 Mar 2021

Cited by 4 | Viewed by 4266

Abstract

The majority of cultivated strawberries (Fragaria × ananassa) in the northern United States (US) and Canadian provinces is grown in perennial matted rows across a range of soil types and microclimates. Management practices vary in fertilization rates, intensity of pesticide use, [...] Read more.

The majority of cultivated strawberries (Fragaria × ananassa) in the northern United States (US) and Canadian provinces is grown in perennial matted rows across a range of soil types and microclimates. Management practices vary in fertilization rates, intensity of pesticide use, and the source of inputs depending on grower preferences. The objective of this study was to identify environmental and management factors that influence strawberry flavor attributes across a range of production systems. The cultivar Jewel was selected for its popularity in this region and reputation for excellent flavor. “Jewel” was sampled from regional farms and, concurrently, grown in a controlled field study with different inputs over three years. Soluble solids content (SSC) and titratable acidity (TA) across farms was found to be positively associated with the air temperature differential during fruit ripening. In controlled field studies, yield was correlated positively with total N in the form of synthetic urea, but not with the rate of applied organic nitrogen (N). Despite different levels of soil carbon inputs, N rates, pesticides, and microbial supplements, the fruit quality attributes, including SSC, TA, aromatic volatile concentration, and phenolics were not associated with treatment. A human sensory evaluation found no perceptible differences in flavor or aroma among contrasting treatments. Our study concludes that growers should invest in temperature management, rather than agricultural inputs, to influence SSC and TA of strawberry. Full article

(This article belongs to the Special Issue Preharvest Practices for High-Quality Strawberry Production)

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Regression between soluble solids content of strawberry fruit at harvest and the mean temperature between green and pink fruit (line A) and pink and red fruit (line B) for 16 farms across New York State visited in 2018, 2019, and 2020. A: y = 0.35x + 0.4, r = 0.39, p = 0.0062. B: y = 0.21x + 3.0, r = 0.36, p = 0.03. Full article ">Figure 2
Regression between soluble solids content of strawberry fruit at harvest and the lowest single temperature between first flower and green fruit for 16 farms across New York State visited in 2018, 2019, and 2020. y = –0.26x + 8.9, r = –0.42, p < 0.0027. Full article ">Figure 3
Regression between final soluble solids content of strawberry fruit at harvest and the difference between mean air temperature and the lowest single temperature between first flower and green fruit (A) and green to pink fruit (B) for 16 farms across New York State visited in 2018, 2019, and 2020. A: y = 0.27x + 4.0, r = 0.43, p< 0.005. B: y = 0.24x + 4.6, r = 0.36, p < 0.05. Full article ">Figure 4
Regression between titratable acidity of strawberry fruit at harvest and the difference between mean air temperature and the lowest single temperature between first flower and green fruit (A) and green to pink fruit (B) for 16 farms across New York State visited in 2018, 2019, and 2020. A: y = 0.37x − 2.8, r = 0.7, p < 0.0001. B: y = 0.38x − 2.6, r = 0.74, p < 0.0001. Full article ">Figure 5
Titratable acidity of “Jewel” between 2018, 2019, and 2020. Each letter corresponds to an individual farm in New York State. One sample was collected per farm between early June and early July. Differences between years were significant (p < 0.0001) when treating farms as replicates, but not between farms when treating year as a replicate. Full article ">Figure 6
Soluble solids content (%) of “Jewel” strawberry in 2018, 2019, and 2020. Each letter corresponds to an individual farm in New York State. One sample was collected per farm between early June and early July. Differences between years were significant (p < 0.05) when treating farms as replicates, but not between farms when treating year as a replicate. Full article ">Figure 7
Estimated concentrations of three esters in “Jewel” across regional farms in New York State. Esters: ethyl hexanoate (EH), ethyl butanoate (EB), isoamyl acetate (IA). Fruits collected between 6 June and 3 July 2018. Gray horizontal line indicates threshold for ester flavor detection: Nasal threshold of ethyl hexanoate at 0.16 m%, orthonasal threshold of ethyl butanoate at 20 m%, and orthonasal threshold of isoamyl acetate at 30 m%. Full article ">Figure 8
Total yield and marketable yield of “Jewel” strawberry for various management practices. Fruits were collected between 19 June and 10 July 2019. Management regimes: Conventional (CON), Organic (ORG), and Low Carbon Conventional (LOC). Treatments fertilized with 50 kg N ha−1 (−), cross hatch up to right, 100 kg ha−1 N (o), no cross hatch, or 100 kg N ha−1 with intensive application of biological supplements (+), cross hatch down to right. Differences between treatments calculated using Tukey’s HSD, where differences in marketable yield were significant at p = 0.094, and differences in total yield significant at p = 0.05. Letters indicating significance are identical for both total and marketable yields. S.E. = standard error of the mean. Full article ">

11 pages, 650 KiB

Open AccessArticle

Individual and Combined Effects of Planting Date, Seeding Rate, Relative Maturity, and Row Spacing on Soybean Yield

by Peder K. Schmitz and Hans J. Kandel

Agronomy 2021, 11(3), 605; https://doi.org/10.3390/agronomy11030605 - 23 Mar 2021

Cited by 5 | Viewed by 3113

Abstract

Planting date (PD), seeding rate (SR), relative maturity (RM) of cultivars, and row spacing (RS) are primary management factors affecting soybean (Glycine max (L.) Merr.) yield. The individual and synergistic effects of PD, SR, RM, and RS on seed yield and agronomic [...] Read more.

Planting date (PD), seeding rate (SR), relative maturity (RM) of cultivars, and row spacing (RS) are primary management factors affecting soybean (Glycine max (L.) Merr.) yield. The individual and synergistic effects of PD, SR, RM, and RS on seed yield and agronomic characteristics in North Dakota were herein investigated. Early and late PD, early and late RM cultivars, two SR (408,000 and 457,000 seed ha⁻¹), and two RS (30.5 and 61 cm) were evaluated in four total environments in 2019 and 2020. Maximizing green canopy cover prior to the beginning of flowering improved seed yield. Individual factors of early PD and narrow RS resulted in yield increase of 311 and 266 kg ha⁻¹, respectively. The combined factors of early PD, late RM, high SR, and narrow RS improved yield by 26% and provided a $350 ha⁻¹ partial profit over conventional practices. Canopy cover and yield had relatively weak relationships with r² of 0.36, 0.23, 0.14, and 0.21 at the two trifoliolate, four trifoliolate, beginning of flowering, and beginning of pod formation soybean growth stages, respectively. Producers in the most northern soybean region of the USA should combine early planting, optimum RM cultivars, 457,000 seed ha⁻¹ SR, and 31 cm RS to improve yield and profit compared to current management practices. Full article

(This article belongs to the Special Issue Soybean Breeding, Agronomic Practices, and Production Systems)

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11 pages, 5853 KiB

Open AccessArticle

Genetic Diversity and Population Structure of Soybean Lines Adapted to Sub-Saharan Africa Using Single Nucleotide Polymorphism (SNP) Markers

by Subhash Chander, Ana Luísa Garcia-Oliveira, Melaku Gedil, Trushar Shah, Gbemisola Oluwayemisi Otusanya, Robert Asiedu and Godfree Chigeza

Agronomy 2021, 11(3), 604; https://doi.org/10.3390/agronomy11030604 - 22 Mar 2021

Cited by 19 | Viewed by 4274

Abstract

Soybean productivity in sub-Saharan Africa (SSA) is less than half of the global average yield. To plug the productivity gap, further improvement in grain yield must be attained by enhancing the genetic potential of new cultivars that depends on the genetic diversity of [...] Read more.

Soybean productivity in sub-Saharan Africa (SSA) is less than half of the global average yield. To plug the productivity gap, further improvement in grain yield must be attained by enhancing the genetic potential of new cultivars that depends on the genetic diversity of the parents. Hence, our aim was to assess genetic diversity and population structure of elite soybean genotypes, mainly released cultivars and advanced selections in SSA. In this study, a set of 165 lines was genotyped with high-throughput single nucleotide polymorphism (SNP) markers covering the complete genome of soybean. The genetic diversity (0.414) was high considering the bi-allelic nature of SNP markers. The polymorphic information content (PIC) varied from 0.079 to 0.375, with an average of 0.324 and about 49% of the markers had a PIC value above 0.350. Cluster analysis grouped all the genotypes into three major clusters. The model-based STRUCTURE and discriminant analysis of principal components (DAPC) exhibited high consistency in the allocation of lines in subpopulations or groups. Nonetheless, they presented some discrepancy and identified the presence of six and five subpopulations or groups, respectively. Principal coordinate analysis revealed more consistency with subgroups suggested by DAPC analysis. Our results clearly revealed the broad genetic base of TGx (Tropical Glycine max) lines that soybean breeders may select parents for crossing, testing and selection of future cultivars with desirable traits for SSA. Full article

(This article belongs to the Special Issue Molecular Genetics, Genomics and Biotechnology of Crop Plants Breeding - Series Ⅱ)

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Graphical abstract
Full article ">Figure 1
Summary statistics of 186 single nucleotide polymorphism (SNP) markers used for genotyping of 155 soybean lines. Marker distribution across chromosomes (a), frequencies of the minor allele frequency (b), gene diversity (c) and polymorphic information content (d). Full article ">Figure 2
Genetic structure of the 155 soybean lines evaluated with 186 SNP markers. (a) The number of subpopulations identified by the LnP(D) and K model with an elevated ΔK value calculated for K varying up to K = 2 to 10; (b) mean of est. Ln prob data. (c) Population structure analysis of the 155 lines accomplished from K = 6. Note: In (c), each individual represents a vertical line divided into K colored segments, with length proportional to the individual coefficient of participation in the K clusters for each cluster and are described at <a href="#app1-agronomy-11-00604" class="html-app">Supplementary Table S3</a>. Full article ">Figure 3
Summary of discriminant analysis of principal components (DAPC) for 155 soybean lines. (a,c), Optimal k number of genetic groups/clusters (a) and the percentage of cumulative variance for the retained principal component analysis (PCA) eigenvectors (c) based on the Bayesian information criterion. (b) Ordination plot of DAPC for the five groups and eigenvalues are given in bottom-right inset. Note: Genetic group/clusters are depicted by different colors and inertia ellipses whereas dots represent genotypes. Full article ">Figure 4
Neighbor-joining phylogenetic tree of the 155 soybean lines based on 186 SNP markers. The color patterns are equivalent to the STRUCTURE analysis (based on >60% identity) at K = 6 (a) and DAPC analysis K = 5 (b). Black color represents admixture inbred line. Full article ">Figure 5
Principal coordinate analysis (PCoA) of the 155 soybean lines. Color-coded according to membership (based on > 60% identity) to subpopulations identified from structure analysis at K = 6 (a) and DAPC analysis K = 5 (b). Note: numerical corresponding with Roman letters designate subpopulations identified by STRUCTURE and DAPC, respectively. Lines belonging to subpopulation 4 (STRUCTURE) are denoted by rectangles. Full article ">

13 pages, 2298 KiB

Open AccessArticle

The Effects of Various Doses and Types of Effective Microorganism Applications on Microbial and Enzyme Activity of Medium and the Photosynthetic Activity of Scarlet Sage

by Klaudia Borowiak, Agnieszka Wolna-Maruwka, Alicja Niewiadomska, Anna Budka, Anita Schroeter-Zakrzewska and Rafał Stasik

Agronomy 2021, 11(3), 603; https://doi.org/10.3390/agronomy11030603 - 22 Mar 2021

Cited by 5 | Viewed by 3309

Abstract

The aim of this study was to examine the influence of various types and levels of effective microorganism (EM) applications on scarlet sage. For this purpose, EMs were applied at the following three concentrations: 1:10, 1:50, and 1:100. Moreover, two types of treatments [...] Read more.

The aim of this study was to examine the influence of various types and levels of effective microorganism (EM) applications on scarlet sage. For this purpose, EMs were applied at the following three concentrations: 1:10, 1:50, and 1:100. Moreover, two types of treatments (spraying and watering) and a combination of the two were also examined. Photosynthetic intensity was analyzed, including the net photosynthesis rate (P_N), stomatal conductance (g_S), and intercellular CO₂ concentration (C_i). Additionally, chlorophyll a, b, and a + b, and the chlorophyll b/a ratio were analyzed. The microbial content in the medium and soil enzyme activity were also evaluated to examine the effect of EMs on soil biological properties. The investigations revealed a high positive effect of EMs on the photosynthetic activity of most EM combinations compared with the control. The greatest positive effect was noted for the highest EM concentration application for both types of treatments. There was no such influence on soil activity. An increase was noted only in the number of fungi and dehydrogenase activity, while the rest of the soil biological status parameters revealed significant variability, and mostly small or no effects were recorded. Full article

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Means ± SE of scarlet sage under various EM treatments. (a) Net photosynthesis rate, PN; (b) Stomatal conductance, gs; (c) Intercellular CO2 concentration, Ci; (d) Transpiration rate electron E. Letters denote significant differences between means at p = 0.05. Full article ">Figure 1 Cont.
Means ± SE of scarlet sage under various EM treatments. (a) Net photosynthesis rate, PN; (b) Stomatal conductance, gs; (c) Intercellular CO2 concentration, Ci; (d) Transpiration rate electron E. Letters denote significant differences between means at p = 0.05. Full article ">Figure 2
(a) Means ± SE chlorophyll a, b, and a + b contents in fresh weight, (b) Chlorophyll b/a ratio. Letters denote significant differences between means at p = 0.05. Full article ">Figure 3
Changes in medium during the growing season. (a) Number of fungi, (b) number of bacteria, (c) number of actinobacteria. Full article ">Figure 4
Changes in activities in the medium during the growing season. (a) Dehydrogenases, (b) phosphatases, (c) ureases. Full article ">Figure 5
Principal component analysis and cluster analysis of obtained results. Numbers indicate certain combinations of EM application. UR, urease; DHA, dehydrogenase; PAC, phosphatase; PN, net photosynthesis rate; CI, internal CO2 concentration; GS, stomatal conductance; E, transpiration rate; actinobact., actinobacteria. Full article ">Figure 6
Cluster analysis of photosynthetic parameters and microbial activity. UR, urease; DHA, dehydrogenase; PAC, phosphatase; PN, net photosynthesis rate; CI, internal CO2 concentration; GS, stomatal conductance; E, transpiration rate; actinobact., actinobacteria. Full article ">

16 pages, 992 KiB

Open AccessEditor’s ChoiceArticle

Enhancement to Salt Stress Tolerance in Strawberry Plants by Iodine Products Application

by Julia Medrano Macías, María Guadalupe López Caltzontzit, Erika Nohemi Rivas Martínez, Willian Alfredo Narváez Ortiz, Adalberto Benavides Mendoza and Paulino Martínez Lagunes

Agronomy 2021, 11(3), 602; https://doi.org/10.3390/agronomy11030602 - 22 Mar 2021

Cited by 26 | Viewed by 5133

Abstract

Iodine is a non-essential element for land plants, but is considered as a beneficial element, related to antioxidant capacity, environmental adaptations and improvement of plant growth. Salinity is one of the more recurrent abiotic stresses worldwide, seriously affecting vegetal production. The aim of [...] Read more.

Iodine is a non-essential element for land plants, but is considered as a beneficial element, related to antioxidant capacity, environmental adaptations and improvement of plant growth. Salinity is one of the more recurrent abiotic stresses worldwide, seriously affecting vegetal production. The aim of this work was to evaluate iodine application (Q products^® and KIO₃, Quimcasa de México, Naucalpan, Mexico) in strawberry plants under normal and salt stress conditions. Growth, antioxidant content, essential minerals, iodine accumulation and fruit quality were evaluated. The results showed that, under stress conditions, the application of Q products increased ascorbate peroxidase (APX) and catalase (CAT) activity as well as glutathione (GSH) content and yield in fruit, without avoiding biomass loss; with the application of KIO₃ an increase in GSH and APX activity as well as P and K concentrations were obtained. In leaves an increase in P, Ca, Mn and iodine accumulation was evidenced with the application of Q products, and an increased concentration of ascorbic acid and iodine with KIO₃ treatments. Under normal conditions in fruits, the application of Q products increased phenolic compounds synthesis; additionally, an increase in Ca and Mn concentrations was shown. KIO₃ application increased the firmness and Mn. In leaves, the application of Q products increased chlorophyll a, b and calcium. In conclusion, the application of iodine improves the quality value of strawberries under normal conditions and provides an enhancement of salt stress tolerance. Full article

(This article belongs to the Special Issue From Biofortification to Tailored Crops and Food Products)

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10 pages, 1316 KiB

Open AccessEditor’s ChoiceArticle

Chemical Properties and Bacterial Community Reaction to Acidified Cattle Slurry Fertilization in Soil from Maize Cultivation

by Paweł Stanisław Wierzchowski, Jakub Dobrzyński, Kamila Mazur, Marek Kierończyk, Witold Jan Wardal, Tomasz Sakowski and Jerzy Barszczewski

Agronomy 2021, 11(3), 601; https://doi.org/10.3390/agronomy11030601 - 22 Mar 2021

Cited by 8 | Viewed by 2776

Abstract

Acidified slurry is a novel organic fertilizer that limits gaseous ammonia emissions and reduces nitrogen losses. Our research aimed to determine the effects of short-term fertilization with acidified slurry on the chemical properties and bacterial community of soil used for maize cultivation. In [...] Read more.

Acidified slurry is a novel organic fertilizer that limits gaseous ammonia emissions and reduces nitrogen losses. Our research aimed to determine the effects of short-term fertilization with acidified slurry on the chemical properties and bacterial community of soil used for maize cultivation. In the months after spreading, raw slurry fertilization had a significant impact on the increase in values of N-NO₃. In contrast, soil fertilized with acidified slurry had lower N-NO₃ values when compared to raw slurry fertilization treatments. Bacterial sequencing using Illumina MiSeq showed no differences in the genetic diversity of bacterial communities. In all tested soil samples, dominants at the phylum level were Actinobacteria, Proteobacteria, and Acidobacteria, while dominants at the class level were Actinobacteria, Alphaproteobacteria, Thermoleophilia, Gammaproteobacteria, and Acidimicrobiia. The values of biodiversity indices (Shannon index, Simpson index) in tested samples were similar. Our results suggest that short-term fertilization with acidified slurry does not adversely affect the biodiversity and structure of the bacterial communities and has a slight impact on soil chemical properties. Full article

(This article belongs to the Special Issue Protection of Biodiversity of Agricultural Soils)

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15 pages, 294 KiB

Open AccessEditor’s ChoiceArticle

Farmers’ Climate Change Adaptation Strategies for Reducing the Risk of Rice Production: Evidence from Rajshahi District in Bangladesh

by Shahjahan Ali, Bikash Chandra Ghosh, Ataul Gani Osmani, Elias Hossain and Csaba Fogarassy

Agronomy 2021, 11(3), 600; https://doi.org/10.3390/agronomy11030600 - 22 Mar 2021

Cited by 21 | Viewed by 5938

Abstract

A lack of adaptive capacities for climate change prevents poor farmers from diversifying agricultural production in Bangladesh’s drought-resilient areas. Climate change adaptation strategies can reduce the production risk relating to unforeseen climatic shocks and increase farmers’ food, income, and livelihood security. This paper [...] Read more.

A lack of adaptive capacities for climate change prevents poor farmers from diversifying agricultural production in Bangladesh’s drought-resilient areas. Climate change adaptation strategies can reduce the production risk relating to unforeseen climatic shocks and increase farmers’ food, income, and livelihood security. This paper investigates rice farmers’ adaptive capacities to adapt climate change strategies to reduce the rice production risk. The study collected 400 farm-level micro-data of rice farmers with the direct cooperation of Rajshahi District. The survey was conducted during periods between June and July of 2020. Rice farmers’ adaptive capacities were estimated quantitatively by categorizing the farmers as high, moderate, and low level adapters to climate change adaptation strategies. In this study, a Cobb–Douglas production function was used to measure the effects of farmers’ adaptive capacities on rice production. The obtained results show that farmers are moderately adaptive in terms of adaptation strategies on climate change and the degree of adaptation capacities. Agronomic practices such as the quantity of fertilizer used, the amount of labor, the farm’s size, and extension contacts have a substantial impact on rice production. This study recommends that a farmer more significantly adjusts to adaptation strategies on climate change to reduce rice production. These strategies will help farmers to reduce the risk and produce higher quality rice. Consequently, rice farmers should facilitate better extension services and change the present agronomic practice to attain a higher adaptation status. It can be very clearly seen that low adaptability results in lower rice yields. Full article

(This article belongs to the Special Issue Smallholder Agriculture: Where We Are and Pathways towards the Future)

19 pages, 1129 KiB

Open AccessArticle

Organic Cultivation and Deficit Irrigation Practices to Improve Chemical and Biological Activity of Mentha spicata Plants

by Antonios Chrysargyris, Eleni Koutsoumpeli, Panayiota Xylia, Anastasia Fytrou, Maria Konstantopoulou and Nikolaos Tzortzakis

Agronomy 2021, 11(3), 599; https://doi.org/10.3390/agronomy11030599 - 22 Mar 2021

Cited by 8 | Viewed by 3205

Abstract

Intensive crop production and irrational use of fertilizers and agrochemicals have questionable effects on the quality of products and the sustainable use of water for agricultural purposes. Organic cultivation and/or deficit irrigation are, among others, well appreciated practices for a sustainable crop production [...] Read more.

Intensive crop production and irrational use of fertilizers and agrochemicals have questionable effects on the quality of products and the sustainable use of water for agricultural purposes. Organic cultivation and/or deficit irrigation are, among others, well appreciated practices for a sustainable crop production system. In the present study, spearmint plants (Mentha spicata L.) were grown in different cultivation schemes (conventional versus organic cultivation, full versus deficit irrigation), and effects on the plant physiological and biochemical attributes were examined in two harvesting periods. Deficit irrigation decreased plant growth, but increased total phenolics, flavonoids, and antioxidant capacity of the plants at the second harvest. Spearmint nutrient accumulation was affected by the examined cultivation practices; nitrogen was decreased in organic cultivation, potassium and sodium were elevated at full-irrigated plants, while magnesium, phosphorus, and copper levels were higher at the deficit-irrigated plants. However, conventional/full-irrigated plants had increased height and fresh biomass at the first harvest. Essential oil content decreased at the second harvest in organic and/or deficit treated plants. Additionally, deficit irrigation affected plant growth and delayed the formation of carvone from limonene. The essential oils were further evaluated with regard to their bioactivity on a major vineyard pest Lobesia botrana. Volatile compounds from all essential oils elicited strong electroantennographic responses on female insects antennae, highlighting the role of carvone, which is the major constituent (~70%) in all the tested essential oils. M. spicata essential oils also exhibited larvicidal activity on L. botrana, suggesting the potential of their incorporation in integrated pest management systems. Full article

(This article belongs to the Special Issue Medicinal and Aromatic Plants (MAPs): The Connection between Cultivation Practices and Biological Properties)

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Figure 1
Effect of cultivation (conventional/organic) and irrigation (full/deficit irrigation) plans on the concentration of nutrients in spearmint leaves. Values represent mean (±SE) of measurements made on four independent replications per treatment. (A) nitrogen—N, (B) potassium—K, (C) phosphorus—P, (D) magnesium—Mg, (E) calcium—Ca, (F) sodium—Na, (G) zinc—Zn, and (H) copper—Cu. Mean values followed by the same letter do not differ significantly at p ≥ 0.05 according to Duncan’s MRT. ns indicates non-significant. Full article ">Figure 1 Cont.
Effect of cultivation (conventional/organic) and irrigation (full/deficit irrigation) plans on the concentration of nutrients in spearmint leaves. Values represent mean (±SE) of measurements made on four independent replications per treatment. (A) nitrogen—N, (B) potassium—K, (C) phosphorus—P, (D) magnesium—Mg, (E) calcium—Ca, (F) sodium—Na, (G) zinc—Zn, and (H) copper—Cu. Mean values followed by the same letter do not differ significantly at p ≥ 0.05 according to Duncan’s MRT. ns indicates non-significant. Full article ">Figure 2
Mean electrophysiological responses of male L. botrana antennae to spearmint essential oils, E7,Z9-12:Ac, 3-octanol, and carvone. Spearmint plants were subjected to different cultivation (conventional/organic) and irrigation (full/deficit irrigation) plans. All stimuli were tested at a 50 μg dose. Means (± SE) followed by the same letter are not significantly different (Duncan’s multiple range tests (MRT) at p < 0.05, F = 19.591, df = 10, p = 0.000). Full article ">

13 pages, 1228 KiB

Open AccessArticle

In Vitro Screening of Sugarcane Cultivars (Saccharum spp. Hybrids) for Tolerance to Polyethylene Glycol-Induced Water Stress

by César A. Hernández-Pérez, Fernando Carlos Gómez-Merino, José L. Spinoso-Castillo and Jericó J. Bello-Bello

Agronomy 2021, 11(3), 598; https://doi.org/10.3390/agronomy11030598 - 22 Mar 2021

Cited by 17 | Viewed by 3860

Abstract

Water stress caused by drought affects the productivity of the sugarcane crop. A breeding alternative is the selection of drought-tolerant sugarcane cultivars. The objective of this study was the in vitro screening of cultivars tolerant to water stress using polyethylene glycol (PEG) as [...] Read more.

Water stress caused by drought affects the productivity of the sugarcane crop. A breeding alternative is the selection of drought-tolerant sugarcane cultivars. The objective of this study was the in vitro screening of cultivars tolerant to water stress using polyethylene glycol (PEG) as a stressing agent. Cultivars (cv) Mex 69-290, CP 72-2086, Mex 79-431 and MOTZMex 92-207 were subjected to different concentrations of PEG 6000 (0, 3, 6 and 9% w/v) using Murashige and Skoog semi-solid culture medium. At 30 days of culture, different developmental variables and dry matter (DM), total protein (TP), proline (Pr) and glycine-betaine (GB) contents were evaluated. The results showed reduced development in cv CP 72-2086, Mex 79-431 and MOTZMex 92-207 with increasing PEG concentration. The cv Mex 69-290 showed tolerance to osmotic stress of −0.45 MPa using 3% PEG. Overall, TP content decreased with increasing PEG concentration, while DM, Pr and GB contents rose with increasing PEG concentration in all evaluated cultivars. Our results suggest that cv Mex 69-290 has a slight tolerance to water stress and could be used for rainfed cultivation with low rainfall or reduced irrigation for better water use efficiency. In conclusion, the in vitro screening technique of cultivars tolerant to PEG-induced water stress is an alternative for early determination of drought stress in sugarcane. Full article

(This article belongs to the Section Crop Breeding and Genetics)

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Figure 1
Effect of different concentrations of PEG-6000 (0, 3, 6, and 9%, left to right) on sugarcane cultivars (Saccharum spp. Hybrids) during in vitro selection. (A) Mex 69-290, (B) Mex 79-431, (C) CP 72-2086 and (D) MOTZMex 92-207. Black bar = 2 cm. Full article ">Figure 2
Effect of different concentrations of PEG-6000 on total protein content in sugarcane cultivars (Saccharum spp. Hybrids). Bars above the columns represent the standard error. Different letters above the columns of each subfigure indicate significant statistical differences among treatments (Tukey, p ≤ 0.05). Full article ">Figure 3
Effect of different concentrations of PEG-6000 on proline content in sugarcane cultivars (Saccharum spp. Hybrids). Bars above the columns represent the standard error. Different letters above the columns of each subfigure indicate significant statistical differences among treatments (Tukey, p ≤ 0.05). Full article ">Figure 4
Effect of different concentrations of PEG-6000 on glycine-betaine content in sugarcane cultivars (Saccharum spp. Hybrids). Bars above the columns represent the standard error. Different letters above the columns of each subfigure indicate significant statistical differences among treatments (Tukey, p ≤ 0.05). Full article ">

20 pages, 8483 KiB

Open AccessArticle

Land Use and Soil Organic Carbon Stocks—Change Detection over Time Using Digital Soil Assessment: A Case Study from Kamyaran Region, Iran (1988–2018)

by Kamal Nabiollahi, Shadi Shahlaee, Salahudin Zahedi, Ruhollah Taghizadeh-Mehrjardi, Ruth Kerry and Thomas Scholten

Agronomy 2021, 11(3), 597; https://doi.org/10.3390/agronomy11030597 - 21 Mar 2021

Cited by 9 | Viewed by 3454

Abstract

Land use change and soil organic carbon stock (SOCS) depletion over time is one of the predominant worldwide environmental problems related to global warming and the need to secure food production for an increasing world population. In our research, satellite images from 1988 [...] Read more.

Land use change and soil organic carbon stock (SOCS) depletion over time is one of the predominant worldwide environmental problems related to global warming and the need to secure food production for an increasing world population. In our research, satellite images from 1988 and 2018 were analyzed for a 177.48 km² region in Kurdistan Province, Iran. Across the study area. 186 disturbed and undisturbed soil samples were collected at two depths (0–20 cm and 20–50 cm). Bulk density (BD), soil organic carbon (SOC), rock fragments (RockF) and SOCS were measured. Random forest was used to model the spatial variability of SOCS. Land use was mapped with supervised classification and maximum likelihood approaches. The Kappa index and overall accuracy of the supervised classification and maximum likelihood land use maps varied between 83% and 88% and 78% and 85%, respectively. The area of forest and high-quality rangeland covered 5286 ha in 1988 and decreased by almost 30% by 2018. Most of the decrease was due to the establishment of cropland and orchards, and due to overgrazing of high-quality rangeland. As expected, the results of the analysis of variance showed that mean values of SOCS for the high-quality rangeland and forest were significantly higher compared to other land use classes. Thus, transformation of land with natural vegetation like forest and high-quality rangeland led to a loss of 15,494 Mg C in the topsoil, 15,475 Mg C in the subsoil and 15,489 Mg C⁻¹ in total. We concluded that the predominant causes of natural vegetation degradation in the study area were mostly due to the increasing need for food, anthropogenic activities such as cultivation and over grazing, lack of government landuse legislation and the results of this study are useful for land use monitoring, decision making, natural vegetation planning and other areas of research and development in Kurdistan province. Full article

(This article belongs to the Special Issue Machine Learning Applications in Digital Agriculture)

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Flowchart of methodology used in this study. Full article ">Figure 2
Composite location map of the study area within the world (A), Iran (B) and Kurdistan Province (C), and digital elevation model (D). Full article ">Figure 3
Soil sampling points on the slope class and physiography maps (A), lithology map (B) and (C) photos of major land use classes in the study area. Full article ">Figure 4
Land use maps for two time steps, 1988 and 2018. Full article ">Figure 5
SOCS and SOCS loss contents at depths of 0–20 cm (surface), 20–50 cm (subsurface) and 0–50 cm (total). Full article ">Figure 6
Significance of each auxiliary variable used in the random forest (RF) learning machine for prediction of surface (0–20 cm,), subsurface (20–50 cm) and total (0–50 cm) soil organic carbon stocks. Full article ">Figure 7
Spatial distribution maps of soil organic carbon stocks predicted with random forests (RF) at depths of 0–20 cm (surface), (subsurface) 20–50 cm and 0–50 cm (total). Full article ">

11 pages, 2270 KiB

Open AccessArticle

In Vitro Polyploidization of Thymus vulgaris L. and Its Effect on Composition of Essential Oils

by Božena Navrátilová, Michaela Švécarová, Jan Bednář and Vladan Ondřej

Agronomy 2021, 11(3), 596; https://doi.org/10.3390/agronomy11030596 - 21 Mar 2021

Cited by 14 | Viewed by 2903

Abstract

The aim of this work was to find an effective protocol for in vitro propagation and to perform the in vitro polyploidization of diploid Thymus vulgaris (2n = 30) using two experimental methods based on the use of oryzalin, an antimitotic agent. The [...] Read more.

The aim of this work was to find an effective protocol for in vitro propagation and to perform the in vitro polyploidization of diploid Thymus vulgaris (2n = 30) using two experimental methods based on the use of oryzalin, an antimitotic agent. The ploidy level of the obtained shoots was checked by flow cytometric analysis. The most efficient conditions for inducing polyploidy were oryzalin concentrations of 0.346 and 1.73 mg L⁻¹ present in the medium for two weeks. The vital polyploid shoots were multiplied for further evaluation, rooting and final transfer to nonsterile glasshouse and field conditions. The chemical compositions of the essential oils (EOs)—which were obtained from dried field grown plants by steam distillation—were analyzed by gas chromatography/mass spectrometry (GC/MS). The identified substances contributed approximately 95% to the total peak area. Statistical analysis revealed that the tetraploid subclone and the diploid reference plant do not differ in total terpene content, but they do differ in the relative proportions of all the individual terpenes with the exception of α-pinene and UN5, indicating that both clones produce EOs of different quality. The obtained results showed the possibility of developing more efficient botanical insecticides based on EOs obtained from the tetraploid plants. Full article

(This article belongs to the Special Issue New Polyploids of Crop Plants—Application in Breeding, Phenotypic and Genetic Evaluation)

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Representative flow cytometric histograms of nuclear DNA contents of T. vulgaris. (A) diploid reference plant and internal standard Zea mays * and (B) tetraploid originated from clone No. 8 and standard Zea mays *. Full article ">Figure 2
Diploid (left) and tetraploid (right) plants of T. vulgaris subclone TR15-22 after five months growing in vitro. Full article ">Figure 3
Plants of T. vulgaris in Jiffy pellets growing for two months ex vitro: diploid (left) and two tetraploid (right) plants from subclone TR15-22. Full article ">Figure 4
Principal component analysis (PCA) on relative abundances of individual terpenes in essential oil from tetraploid subclone (TR15-22) and the diploid reference subclone (TR15-K). Bor, borneol; Camp, camphor; Carv, carvacrol; α-Pin, a-pinene; t-Car, trans-caryophyllene; 4-Cym, 4-cymene; Lin, linalool; Myr + UN, myrcene + UN; γ-Ter, g-terpinene; T-4-ol, terpinen-4-ol; Thym, thymol; UN1-5, unknown compound 1-5. Full article ">

9 pages, 454 KiB

Open AccessArticle

Investigating the Efficacy of Selected Very-Long-Chain Fatty Acid-Inhibiting Herbicides on Iowa Waterhemp (Amaranthus tuberculatus) Populations with Evolved Multiple Herbicide Resistances

by Eric A. L. Jones and Micheal D. K. Owen

Agronomy 2021, 11(3), 595; https://doi.org/10.3390/agronomy11030595 - 21 Mar 2021

Viewed by 2414

Abstract

Very long chain fatty acid (VLCFA)-inhibiting herbicides (Herbicide group (HG) 15) have been applied to corn and soybean fields in Iowa since the 1960s. The VLCFA-inhibiting herbicides are now applied more frequently to control multiple herbicide-resistant (MHR) waterhemp (Amaranthus tuberculatus Moq. J.D. [...] Read more.

Very long chain fatty acid (VLCFA)-inhibiting herbicides (Herbicide group (HG) 15) have been applied to corn and soybean fields in Iowa since the 1960s. The VLCFA-inhibiting herbicides are now applied more frequently to control multiple herbicide-resistant (MHR) waterhemp (Amaranthus tuberculatus Moq. J.D. Sauer) populations that are ubiquitous across the Midwest United States as resistance to the VLCFA-inhibiting herbicides is not widespread. Waterhemp has evolved multiple resistances to herbicides from seven sites of action (HG 2, 4, 5, 9, 14, 15, and 27), and six-way herbicide-resistant populations have been confirmed. Thus, the objective of this study was to determine if selected Iowa waterhemp populations are less sensitive to VLCFA-inhibiting herbicides when additional herbicide resistance traits have evolved within the selected population. Dose–response assays were conducted in a germination chamber to determine the efficacy of three selected VLCFA-inhibiting herbicides (acetochlor, S-metolachlor, and flufenacet) on selected Iowa MHR waterhemp populations. An herbicide-susceptible, three-way, four-way, and five-way herbicide-resistant waterhemp population responded to the herbicide treatments differently; however, several of the four-way and five-way herbicide-resistant populations exhibited resistance ratios greater than 1 when treated with acetochlor and S-metolachlor. Selected four-way herbicide-resistant waterhemp populations from Iowa were subjected to a dose–response assay in the field using the same VLCFA-inhibiting herbicides, and all herbicides achieved control greater than 80% at the maximum labeled rate. The results of the experiments provide evidence that some MHR waterhemp populations may exhibit decreased susceptibility the VLCFA-inhibiting herbicides, but generally, these herbicides remain efficacious on Iowa MHR waterhemp populations. Full article

(This article belongs to the Section Weed Science and Weed Management)

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Waterhemp control with acetochlor (A), S-metolachlor (B), and flufenacet (C) applied at the multiplicative of the maximum labeled rate (X) on 4-way herbicide-resistant waterhemp populations from Grundy (2016) and Story County (2017), Iowa 28 days after crop emergence under field conditions. Herbicide and rate were significant effects (p < 0.001) on waterhemp control, while the population was not (p = 0.90). No significant interactions were detected. The lethal dose to control 50% of the plants (LD50) and the lethal dose to control 90% of the plants (LD90) for acetochlor was below the maximum labeled rate for both populations (LD50: Grundy County = 0.18x, Story County = 0.22x; LD90: Grundy County = 0.58x; Story County = 0.50x). The LD50 for S-metolachlor was under the maximum labeled rate for both populations (Grundy County = 0.44x; Story County = 0.37x), while the LD90 was above the maximum labeled rate (Grundy County = 1.35x; Story County = 1.53x), The LD50 for flufenacet on the Grundy County population was under the maximum labeled rate (0.67x), but an LD90 could not be calculated with the tested rates. The LD50 and LD90 for flufenacet on the Story County population was below the maximum labeled rate (LD50 = 0.26x; LD90 = 0.82x). The rates needed to achieve the LD50 and LD90 were calculated from 4-parameter sigmodal curves. Acetochlor: Grundy County = −13365 + 13465/(1 + exp (−(X + 1.24)/0.25)), r2 = 0.99; Story County = −4.9 + 93.6/(1 + exp (−(X–0.2)/0.07)), r2 = 0.97. S-metolachlor: Grundy County = 7−9674 + 79769/(1 + exp(−(X + 3.3)/0.5)), r2 = 0.98; Story County = −38.6 + 131/(1 + exp(−(X + 0.2)/0.3)), r2 = 0.93. Flufenacet: Grundy County = 0.6 + 81.2/(−(X + 0.6)/0.2)), r2 = 0.97; Story County = −202.8 + 300.4/(−(X + 0.2)/0.34)), r2 = 0.99. Full article ">

11 pages, 1537 KiB

Open AccessArticle

Foliar Thidiazuron Promotes the Growth of Axillary Buds in Strawberry

by Yali Li, Jiangtao Hu, Jie Xiao, Ge Guo and Byoung Ryong Jeong

Agronomy 2021, 11(3), 594; https://doi.org/10.3390/agronomy11030594 - 21 Mar 2021

Cited by 6 | Viewed by 3303

Abstract

Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their [...] Read more.

Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their combinations on the axillary bud growth in strawberry. Four cytokinins (6-benzyladenine, kinetin, zeatin, and thidiazuron (TDZ)) and three auxins (indole-3-acetic acid, indole-3-butyric acid, and naphthaleneacetic acid) at a concentration of 50 mg·L⁻¹ were sprayed on the leaves three times in 10-day intervals. The expression levels of cytokinin, auxin, and meristem-related genes in the crowns were also investigated. The results showed that TDZ was the most effective hormone for the axillary bud growth, and also promoted plant growth. However, chlorophyll, soluble sugar, and starch contents in the leaves were lower after TDZ. TDZ activated the cytokinin signal transduction pathway, while repressing the auxin synthesis genes. Several meristem-related transcription factors were upregulated, which might be essential for the growth of the axillary buds. These results suggested that TDZ can improve the cultivation of strawberry, while further research is needed to explain the effect on phytochemistry. Full article

(This article belongs to the Special Issue Strawberry Production in a Protected Environment and under Field Conditions)

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The effect of cytokinin and auxin on the morphology of the crown (a), and on the number of runners (b) and branch crowns (c) per plant in strawberry. Lowercase letters indicate significant differences calculated by Duncan’s multiple range test at p ≤ 0.05. Vertical bars indicate the standard error (n = 3). Full article ">Figure 2
The effect of cytokinin and auxin on chlorophyll contents in strawberry leaves. FW: Fresh weight. Lowercase letters indicate significant differences calculated by Duncan’s multiple range test at p ≤ 0.05. Vertical bars indicate the standard error (n = 3). Full article ">Figure 3
The effect of cytokinin and auxin on soluble sugar (a) and starch (b) contents in strawberry. Lowercase letters indicate significant differences calculated by Duncan’s multiple range test at p ≤ 0.05. Vertical bars indicate the standard error (n = 3). Full article ">Figure 4
The effect of TDZ on the cytokinin (a) and auxin (b) metabolism-related genes and meristem-related transcriptional factors (c) in strawberry. The significant differences were calculated by Student’s t-test. NS, and * represent non-significant or significant at p ≤ 0.05, respectively. Full article ">

24 pages, 2404 KiB

Open AccessEditor’s ChoiceArticle

Techno-Economic Viability of Agro-Photovoltaic Irrigated Arable Lands in the EU-Med Region: A Case-Study in Southwestern Spain

by Guillermo P. Moreda, Miguel A. Muñoz-García, M. Carmen Alonso-García and Luis Hernández-Callejo

Agronomy 2021, 11(3), 593; https://doi.org/10.3390/agronomy11030593 - 20 Mar 2021

Cited by 31 | Viewed by 6878

Abstract

Solar photovoltaic (PV) energy is positioned to play a major role in the electricity generation mix of Mediterranean countries. Nonetheless, substantial increase in ground-mounted PV installed capacity could lead to competition with the agricultural use of land. A way to avert the peril [...] Read more.

Solar photovoltaic (PV) energy is positioned to play a major role in the electricity generation mix of Mediterranean countries. Nonetheless, substantial increase in ground-mounted PV installed capacity could lead to competition with the agricultural use of land. A way to avert the peril is the electricity-food dual use of land or agro-photovoltaics (APV). Here, the profitability of a hypothetical APV system deployed on irrigated arable lands of southwestern Spain is analyzed. The basic generator design, comprised of fixed-tilt opaque monofacial PV modules on a 5 m ground-clearance substructure, featured 555.5 kWp/ha. Two APV shed orientations, due south and due southwest, were compared. Two 4-year annual-crop rotations, cultivated beneath the heightened PV modules and with each rotation spanning 24 ha, were studied. One crop rotation was headed by early potato, while the other was headed by processing tomato. All 9 crops involved fulfilled the two-fold condition of being usually cultivated in the area and compatible with APV shed intermitent shading. Crop revenues under the partial shading of PV modules were derived from official average yields in the area, through the use of two alternative sets of coefficients generated for low and high crop-yield shade-induced penalty. Likewise, two irrigation water sources, surface and underground, were compared. Crop total production costs, PV system investment and operating costs and revenues from the sale of electricity, were calculated. The internal rates of return (IRRs) obtained ranged from a minimum of 3.8% for the combination of southwest orientation, early-potato rotation, groundwater and high shade-induced crop-yield penalty, to a maximum of 5.6% for the combination of south orientation, processing-tomato rotation, surface water and low shade-induced crop-yield penalty. Full article

(This article belongs to the Special Issue Photovoltaics and Electrification in Agriculture)

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Figure 1
Spatial distribution of the four plots totalizing 24 ha, the medium voltage power transmission line budgeted and the pre-existing grid-connection switchyard. Full article ">Figure 2
Basic Southwest-oriented agrophotovoltaic shed featuring an installed PV capacity of 153.1 kWp and connected to a 150 kW inverter. Full article ">Figure 3
Annual AC energy output as predicted by PV simulator SISIFO [<a href="#B23-agronomy-11-00593" class="html-bibr">23</a>] for the southwest-oriented APV system in Brenes, Seville, Spain. Full article ">Figure A1
Due south APV shed. Ground area: 26 m × 106 m. Dimensions and number of PV module supporting structures: 26 m × 3.28 m × 11. Equidistance between supporting structures axes: 9.5 m, as in <a href="#agronomy-11-00593-f002" class="html-fig">Figure 2</a>. Full article ">Figure A2
Due southwest APV shed. Full article ">Figure A3
Time series (1 min step) shaded fraction histogram (zero values excluded) for due south orientation. Full article ">Figure A4
Time series (1 min step) shaded fraction histogram (zero-values excluded) for due southwest orientation. Full article ">

16 pages, 3721 KiB

Open AccessArticle

Impact of Pests on Cereal Grain and Nutrient Yield in Boreal Growing Conditions

by Katja Kauppi, Ari Rajala, Erja Huusela, Janne Kaseva, Pentti Ruuttunen, Heikki Jalli, Laura Alakukku and Marja Jalli

Agronomy 2021, 11(3), 592; https://doi.org/10.3390/agronomy11030592 - 20 Mar 2021

Cited by 11 | Viewed by 6174

Abstract

The effect of weeds, plant diseases and insect pests on spring barley (Hordeum vulgare) and spring wheat (Triticum aestivum) grain and nutrient yield was examined. Long-term field trial data was used to assess the impact of different pests on [...] Read more.

The effect of weeds, plant diseases and insect pests on spring barley (Hordeum vulgare) and spring wheat (Triticum aestivum) grain and nutrient yield was examined. Long-term field trial data was used to assess the impact of different pests on grain yield. In the absence of pesticides, fungal diseases caused the largest annual yield-reduction in spring wheat and spring barley, 500 kg ha⁻¹ on average. Converting yield loss to nutrient yield loss this represented reductions of 8.1 and 9.2 kg ha⁻¹ in nitrogen and 1.5 and 1.6 kg ha⁻¹ in phosphorus, respectively. Likewise, it was estimated that weeds decrease the yield of spring barley and spring wheat for 200 kg ha⁻¹, which means reductions of 3.7 and 3.2 kg ha⁻¹ in nitrogen and 0.6 kg ha⁻¹ in phosphorus, respectively. For insect pests yield-reduction in spring barley and spring wheat varied between 418 and 745 kg ha⁻¹ respectively. However, because bird cherry-oat aphid (Rhopalosiphum padi L.) incidence data was limited, and aphids are highly variable annually, nutrient yield losses caused by insect pests were not included. Based on the current study, the management of weeds, plant diseases and insects maintain cereal crop yield and may thus decrease the environmental risks caused by unutilized nutrients. Full article

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Flow chart of the analyses for different data. Full article ">Figure 2
Different growth zones (I–V), 60 degree latitude zone and trial sites in Finland. 1 = Inkoo, 2 = Jokioinen, 3 = Kaarina, 4 = Tikkurila, 5 = Nousiainen and 6 = Ylistaro. Full article ">Figure 3
The yield response (at 15% grain moisture content) of spring barley (blue) and spring wheat (red) in 1965–2012 in different biomass classes (1–5) of weeds. The ranges of the classes are shown in parenthesis. The class medians of weed biomasses were 52, 106, 214, 415 and 959 kg ha−1, respectively. Bars denote the 95% confidence interval for the means. The yield loss is calculated by subtracting the treated crop yield from the untreated crop yield. Full article ">Figure 4
The yield response (at 15% grain moisture content) in 1999–2016 of spring barley according to the allocated class (1–5) of total disease severity (%) for net blotch (red), scald (blue) and powdery mildew (yellow) at BBCH 73–77. The ranges of the classes are shown in parenthesis. Bars denote the 95% confidence interval for the means. The yield loss is calculated by subtracting the treated crop from the untreated crop. Full article ">Figure 5
The yield response (at 15% grain moisture content) in 1999–2016 of spring wheat by class of total disease severity (%) of leaf blotch diseases (red), powdery mildew (yellow) and leaf rust (blue) at BBCH 73–77. The ranges of the classes are shown in parenthesis. Bars denote the 95% confidence interval for the means. The yield loss is calculated by subtracting the treated crop from the untreated crop. Full article ">Figure 6
The yield response (at 15% grain moisture content) in 1999–2008 of spring barley, spring wheat and oat caused by different aphid-abundance classes of bird cherry-oat aphids (number plant−1). The ranges of the classes are shown in parenthesis. Bars denote the 95% confidence interval for the means. The yield loss is calculated by subtracting the treated crop from the untreated crop. Full article ">

16 pages, 1160 KiB

Open AccessArticle

Effect of Sowing Date on Bioactive Compounds and Grain Morphology of Three Pigmented Cereal Species

by Romina Beleggia, Donatella B. M. Ficco, Franca M. Nigro, Valentina Giovanniello, Salvatore A. Colecchia, Ivano Pecorella and Pasquale De Vita

Agronomy 2021, 11(3), 591; https://doi.org/10.3390/agronomy11030591 - 20 Mar 2021

Cited by 11 | Viewed by 2737

Abstract

Recently, the interest in improving the content of bioactive compounds for enhancing the nutritional value of cereal-based products has largely increased, and several strategies, both genetic and agronomic, were proposed. Here, we report the preliminary results of the effect of two sowing periods [...] Read more.

Recently, the interest in improving the content of bioactive compounds for enhancing the nutritional value of cereal-based products has largely increased, and several strategies, both genetic and agronomic, were proposed. Here, we report the preliminary results of the effect of two sowing periods (winter and spring) on the accumulation of bioactive compounds (i.e., anthocyanins, carotenoids, minerals) and grain morphology in three pigmented cereal species (barley, bread and durum wheat). The results showed that with delayed sowing time, a significant reduction in yield was observed in all species, less in barley (50.4%) than in wheat (70.3% and 66.5% for bread and durum, respectively). On the contrary, the carotenoids accumulation was favored (increased by 12.2%, 15.7% and 27.8% for barley, bread and durum wheat, respectively), as well as those of anthocyanins although strongly dependent on the genotype (i.e., considering only the purple genotypes, the anthocyanins increase by 4.6%, 35.4% and 72.8% in barley, bread and durum wheat, respectively). For minerals compounds, our study highlighted a strong environmental influence even when the pigmented genotypes accumulated more minerals than commercial ones, while the morphometric seed traits were less influenced by this agronomic practice. Therefore, by exploiting the genetic variability for the accumulation of anthocyanins and carotenoids in the grain and by optimizing the sowing time, it could be possible to increase the nutritional value of the final cereal-based products. Full article

(This article belongs to the Special Issue From Biofortification in Microelements of Grains to Food Products by Traditional and Innovative Methods)

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11 pages, 1292 KiB

Open AccessArticle

Influence of Fly Ash and Polyacrylamide Mixtures on Growth Properties of Artemisia ordosica in the Desert Region of North China

by Jiping Niu, Xiaoling Su and Zejun Tang

Agronomy 2021, 11(3), 590; https://doi.org/10.3390/agronomy11030590 - 20 Mar 2021

Cited by 5 | Viewed by 1934

Abstract

This study investigated the effects of consolidated soil layer (CSL) composed of fly ash (FA) and polyacrylamide (PAM) on the growth of Artemisia ordosica through plot experiments in Inner Mongolia, North China. It could provide a feasibility reference for ecological restoration and combating [...] Read more.

This study investigated the effects of consolidated soil layer (CSL) composed of fly ash (FA) and polyacrylamide (PAM) on the growth of Artemisia ordosica through plot experiments in Inner Mongolia, North China. It could provide a feasibility reference for ecological restoration and combating desertification in the desert areas. The germination and growth characteristics of Artemisia ordosica were studied in the control soil and 6 kinds of CSL, which were formed with 3 addition rates of FA (5%, 10%, and 15% (w/w) soil) and 2 addition rates of PAM (0.006% and 0.012% (w/w) soil). The results showed that CSL could provide good growth conditions for Artemisia ordosica in arid regions, especially for plant height, basal diameter, total fresh weight, and total dry weight in F5P1 as seen in 2017 and 2018. The FA, the PAM, and the interaction of FA and PAM all had significant impacts on the percentage of seedling emergence and total fresh weight (p < 0.05). The effects of CSL on the emergence and growth properties of Artemisia ordosica were evaluated by principal component analysis, and the CSL consisting of 5% FA and 0.006% PAM was recommended for plant growth. Full article

(This article belongs to the Section Soil and Plant Nutrition)

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14 pages, 2784 KiB

Open AccessArticle

Effects of Light Orientation and Mechanical Damage to Leaves on Isoflavone Accumulation in Soybean Seeds

by Giuseppe Barion, Mohamed Hewidy, Anna Panozzo, Andrea Aloia and Teofilo Vamerali

Agronomy 2021, 11(3), 589; https://doi.org/10.3390/agronomy11030589 - 20 Mar 2021

Cited by 2 | Viewed by 1942

Abstract

Soybean is largely cultivated worldwide providing high amounts of proteins and oil for food and feed, and isoflavones for nutraceutical uses. The increasing interest in agroforestry practices for improving carbon sequestration and mitigating climate changes suggests the need to assess soybean response to [...] Read more.

Soybean is largely cultivated worldwide providing high amounts of proteins and oil for food and feed, and isoflavones for nutraceutical uses. The increasing interest in agroforestry practices for improving carbon sequestration and mitigating climate changes suggests the need to assess soybean response to variations of light availability and direction. A two-year pot trial was carried out at Legnaro (NE Italy) in order to mimic the response of the soybean var. Sponsor to contrasting light orientation (east or west) by artificial shading, associated or not with mechanical leaf damage, in terms of protein accumulation, total cotyledon isoflavone concentration (TCIC) and isoflavone profile. Here, we demonstrate that a different intensity of the isoflavone metabolism exists in response to lighting conditions, with higher TCIC and slightly increased seed crude proteins in plants lighted from the east (morning time) and after mechanical leaf damage. The isoflavone profile was not changed, but low temperatures and high rainfall during seed filling (1st year) were associated with increased accumulation of medium-high molecular weight (MW) forms (i.e., glycosyls and malonyls), while high temperatures and low rainfall (2nd year) with increased accumulation of medium-low MW forms (i.e., glycosyls and aglycones). It is concluded that within agroforestry systems, there is possibly a large scope for maximizing isoflavone accumulation by selecting the harvesting area in the neighboring of the east side of the tree alleys, with further improvements if a mild shoot stripping is applied before flowering. Full article

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16 pages, 1814 KiB

Open AccessArticle

The Use of the Generalized Linear Model to Assess the Speed and Uniformity of Germination of Corn and Soybean Seeds

by Deoclecio Jardim Amorim, Amanda Rithieli Pereira dos Santos, Gabriela Nunes da Piedade, Rute Quelvia de Faria, Edvaldo Aparecido Amaral da Silva and Maria Márcia Pereira Sartori

Agronomy 2021, 11(3), 588; https://doi.org/10.3390/agronomy11030588 - 19 Mar 2021

Cited by 4 | Viewed by 2948

Abstract

The use of seeds with high physiological quality allows rapid growth and establishment of seedlings in the field to be obtained. Therefore, the accuracy of the information obtained during the determination of the physiological quality of seeds is of great importance. The objective [...] Read more.

The use of seeds with high physiological quality allows rapid growth and establishment of seedlings in the field to be obtained. Therefore, the accuracy of the information obtained during the determination of the physiological quality of seeds is of great importance. The objective was to use generalized linear models, investigating which link function (Probit, Logit and Complementary log-log) is suitable to predict T50 and uniformity during germination of soybean and corn seeds. To perform the experiments, we used seeds from five commercial hybrids and/or cultivars of corn and soybean. The germination speed was calculated by counting the germinated seeds and the results were expressed in the form of proportions. Germination uniformity was calculated by the difference in the times required for germination. The best model was selected according to the criteria of the test of Deviance, AIC and BIC. The Logit model showed accurate results for most cultivars. The evaluation of germination in the form of proportions considering the assumption of binomial response is satisfactory, and the choice of the link function is dependent on the characteristics of each lot and/or species evaluated. The use of this methodology makes it possible to estimate any germination time and uniformity. Full article

(This article belongs to the Special Issue Seed Dormancy and Germination as Key for Crop Establishment and Food Production)

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19 pages, 2290 KiB

Open AccessArticle

Polarity-Based Sequential Extraction as a Simple Tool to Reveal the Structural Complexity of Humic Acids

by Vojtěch Enev, Petr Sedláček, Leona Kubíková, Šárka Sovová, Leoš Doskočil, Martina Klučáková and Miloslav Pekař

Agronomy 2021, 11(3), 587; https://doi.org/10.3390/agronomy11030587 - 19 Mar 2021

Cited by 10 | Viewed by 4127

Abstract

A sequential chemical extraction with a defined series of eluotropic organic solvents with an increasing polarity (trichloromethane < ethyl acetate < acetone < acetonitrile < n-propanol < methanol) was performed on peat-bog humic acid. Six organic fractions were obtained and subjected to [...] Read more.

A sequential chemical extraction with a defined series of eluotropic organic solvents with an increasing polarity (trichloromethane < ethyl acetate < acetone < acetonitrile < n-propanol < methanol) was performed on peat-bog humic acid. Six organic fractions were obtained and subjected to a physicochemical characterization utilizing methods of structural and compositional analysis. Advanced spectroscopic techniques such as Attenuated Total Reflectance (ATR-FTIR), total luminescence, and liquid-state ¹³C NMR spectrometry were combined with elemental analysis of the organic fractions. In total, the procedure extracted about 57% (wt.) of the initial material; the individual fractions amounted from 1.1% to 19.7%. As expected, the apolar solvents preferentially released lipid-like components, while polar solvents provided organic fractions rich in oxygen-containing polar groups with structural parameters closer to the original humic material. The fraction extracted with acetonitrile shows distinct structural features with its lower aromaticity and high content of protein-like structural motifs. The last two—alcohol extracted—fractions show the higher content of carbohydrate residues and their specific (V-type) fluorescence suggests the presence of plant pigment residues. The extraction procedure is suggested for further studies as a simple but effective way to decrease the structural complexity of a humic material enabling its detail and more conclusive compositional characterization. Full article

(This article belongs to the Special Issue Humic Substances: A Novel Eco-Friendly Fertilizer)

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13 pages, 1894 KiB

Open AccessArticle

The Evaluation of Agronomic Traits of Wild Soybean Accessions (Glycine soja Sieb. and Zucc.) in Heilongjiang Province, China

by Wei Li, Mu Peng, Zhen Wang, Yingdong Bi, Miao Liu, Ling Wang, Shufeng Di, Jianxin Liu, Chao Fan, Guang Yang and Deyue Yu

Agronomy 2021, 11(3), 586; https://doi.org/10.3390/agronomy11030586 - 19 Mar 2021

Cited by 7 | Viewed by 3088

Abstract

Wild soybean germplasm is distributed widely in China, particularly in Heilongjiang Province. In this study, 242 wild soybean accessions from four agricultural divisions in Heilongjiang Province were evaluated based on six qualitative and eight quantitative traits. Results showed that a large amount of [...] Read more.

Wild soybean germplasm is distributed widely in China, particularly in Heilongjiang Province. In this study, 242 wild soybean accessions from four agricultural divisions in Heilongjiang Province were evaluated based on six qualitative and eight quantitative traits. Results showed that a large amount of variation occurred in these evaluated traits. Abundant qualitative traits included the wild type (78.51%), purple flowers (90.50%), needle leaf (39.26%), black seed (83.88%), brown hilum (52.07%), and mud film (87.60). Results of multivariate analysis based on quantitative traits showed that 100-seed weight, seeds weight per plant, number of seeds per plant, number of effective pods, and number of invalid pods were significantly different among samples (p < 0.05). A total of 27 germplasms were screened. Cluster analysis identified the 242 accessions into two groups, not following the geographical distribution pattern, with rich wild soybean resources revealed in the northern site. The present study indicated that wild soybean in Heilongjiang Province should be conserved in situ. The rich genetic diversity revealed in soybeans of different sites in Heilongjiang Province suggested its significant potential utilization in genetic improvement and breakthrough for soybean breeding. This information will help to exploit and conserve wild soybean accessions in Heilongjiang Province. Full article

(This article belongs to the Special Issue Recent Progress in Molecular Investigations of Crop Plants and Crop Plant–Environment Interactions from Genetic and Genomic Perspectives: Applications and Challenges)

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11 pages, 1171 KiB

Open AccessArticle

Identification of Superior Soybean Cultivars through the Indication of Specific Adaptabilities within Duo-Environments for Year-Round Soybean Production in Northeast Thailand

by Chompoonut Sritongtae, Tidarat Monkham, Jirawat Sanitchon, Sanit Lodthong, Sittipong Srisawangwong and Sompong Chankaew

Agronomy 2021, 11(3), 585; https://doi.org/10.3390/agronomy11030585 - 19 Mar 2021

Cited by 8 | Viewed by 3302

Abstract

The soybean (Glycine max (L.) Merrill) is one of the world’s most important sources of food, feed, and fuel due to its high protein value and oil content. However, there exists a lack of soybean genotypes suitable for growth in diverse conditions [...] Read more.

The soybean (Glycine max (L.) Merrill) is one of the world’s most important sources of food, feed, and fuel due to its high protein value and oil content. However, there exists a lack of soybean genotypes suitable for growth in diverse conditions as soybean breeders have developed their own varieties for specific purposes within their own unique environments. This, therefore, creates the need for soybean genotypes for different environments. The objectives of the experiment described herein were to determine the genotype magnitude through the environment interaction (GxE) of new soybean breeding lines, thereby identifying widely and/or specifically adapted genotypes under ten of Northeast Thailand’s typical environmental conditions from 2017 to 2019. Analyses of the environment (E) and GxE captured a large portion of the total sum of squares of grain yield and related traits, which demonstrated the influence of the two factors in evaluating soybean genotypes, thereby identifying the need for response analysis to identify superior genotypes in each environment. Based on the grain yields of three environments, four genotype groups were clustered. Within the high grain yield environment (EG1), we identified five genotypes with higher yield performance (35*sj-32 (3356 kg/ha), 38D*a-16 (3138 kg/ha), 42*Ly-50-2 (3122 kg/ha), 35*Lh-7 (3116 kg/ha), and 223*Lh-85 (3073 kg/ha)) of KK (3132 kg/ha), the recommended soybean variety for Northeast Thailand, than that of the CM60 (2606 kg/ha). These five top-yielding genotypes, however, produced unstable grain yields through varied environments as they were each narrowly adapted to a specific environment. Moreover, those genotypes may be grown within a rotational cropping system in a duo-environment (wet and dry season) of soybean production in Thailand’s northeast region. Full article

(This article belongs to the Special Issue Legume Breeding and Genetic Improvement for Adaptation of Climate Change)

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12 pages, 2215 KiB

Open AccessArticle

High-Density Poplar SRC Accumulates More Soil Organic Carbon Than Very-High-Density SRC

by Chiara Ferré, Gaia Mascetti and Roberto Comolli

Agronomy 2021, 11(3), 584; https://doi.org/10.3390/agronomy11030584 - 19 Mar 2021

Cited by 3 | Viewed by 2290

Abstract

Short rotation coppice (SRC) systems play an important role in producing renewable energy and contributing to soil organic carbon storage while providing potential mitigation for climate change. Our chronosequence study assessed the influence of 6 years of high-density (H) and very-high-density (VH) SRCs [...] Read more.

Short rotation coppice (SRC) systems play an important role in producing renewable energy and contributing to soil organic carbon storage while providing potential mitigation for climate change. Our chronosequence study assessed the influence of 6 years of high-density (H) and very-high-density (VH) SRCs on soil organic carbon (SOC) accumulation in an alluvial area of Piedmont (Italy) by investigating the effects of agronomic management (fertilization, irrigation, fertilization and irrigation, no treatment) using a spatial survey approach. A first sampling was performed at 40 points to characterize the variability of the initial SOC and other soil properties; 6 years after, a total of 80 samplings were carried out to verify changes in SOC. A mixed effect model procedure was used to evaluate the impact of 6 years of SRC and agronomic management on SOC, testing for autocorrelation among the model residuals. The results showed: (i) a higher accumulation potential of H-SRC (0.076 kg m⁻² year⁻¹) compared to VH-SRC (0.037 kg m⁻² year⁻¹); (ii) a significant positive influence of the initial SOC value and of fertilization associated with irrigation on the SOC sequestration; (iii) the importance of considering spatial variability at sites with high particle-size diversity in evaluating the SOC changes. Full article

(This article belongs to the Special Issue Soil-Climate Conditions and the State of Organic Matter and Nutrients)

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17 pages, 3365 KiB

Open AccessArticle

Using Machine Learning and Hyperspectral Images to Assess Damages to Corn Plant Caused by Glyphosate and to Evaluate Recoverability

by Ting Zhang, Yanbo Huang, Krishna N. Reddy, Pingting Yang, Xiaohu Zhao and Jingcheng Zhang

Agronomy 2021, 11(3), 583; https://doi.org/10.3390/agronomy11030583 - 19 Mar 2021

Cited by 13 | Viewed by 2389

Abstract

Glyphosate is the most widely used herbicide in crop production due to the widespread adoption of glyphosate-resistant (GR) crops. However, the spray of glyphosate onto non-target crops from ground or aerial applications can cause severe injury to non-GR corn plants. To evaluate the [...] Read more.

Glyphosate is the most widely used herbicide in crop production due to the widespread adoption of glyphosate-resistant (GR) crops. However, the spray of glyphosate onto non-target crops from ground or aerial applications can cause severe injury to non-GR corn plants. To evaluate the crop damage of the non-GR corn plants from glyphosate and the recoverability of the damaged plants, we used the hyperspectral imaging (HSI) technique in field experiments with different glyphosate application rates. This study investigated the spectral characteristic of corn plants and assessed the corn plant damage from glyphosate. Based on HSI image analysis, a spectral variation pattern was observed at 1 week after treatment (WAT), 2 WAT, and 3 WAT from the glyphosate-treated non-GR corn plants. It was further found that the corn plants treated with glyphosate rates equal to or higher than 0.5X (X = 0.866 kilograms acid equivalents/hectare (kg ae/ha) represents the recommended spray rate for GR corn) would suffer unrecoverable damage. Using the Jeffries–Matusita distance as the spectral sensitivity criterion, three sensitive bands from the measured spectra were selected to create two spectral indices for crop recoverability differentiation in band ratio and normalization forms, respectively. With the two spectral indices, the corn plants recoverable and unrecoverable from damage were classified with an overall accuracy greater than 95%. Then, three machine learning algorithms (k-nearest neighbors, random forest, and support vector machine) were respectively combined with the successive projections algorithm to create models to relate selected feature spectral bands to glyphosate spray rates. The results indicated that the models achieved reasonable accuracy, especially in the group of recoverable plants. This study illustrated the potential of the hyperspectral imaging technique for evaluating crop damage from herbicides and recoverability of the injured plants using different data analysis and machine learning modeling approaches for practical weed management in crop fields. Full article

(This article belongs to the Section Precision and Digital Agriculture)

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17 pages, 3197 KiB

Open AccessEditor’s ChoiceArticle

A Sustainable Approach for Improving Soil Properties and Reducing N₂O Emissions Is Possible through Initial and Repeated Biochar Application

by Ján Horák, Tatijana Kotuš, Lucia Toková, Elena Aydın, Dušan Igaz and Vladimír Šimanský

Agronomy 2021, 11(3), 582; https://doi.org/10.3390/agronomy11030582 - 19 Mar 2021

Cited by 17 | Viewed by 3034

Abstract

Recent findings of changing climate, water scarcity, soil degradation, and greenhouse gas emissions have brought major challenges to sustainable agriculture worldwide. Biochar application to soil proves to be a suitable solution to these problems. Although the literature presents the pros and cons of [...] Read more.

Recent findings of changing climate, water scarcity, soil degradation, and greenhouse gas emissions have brought major challenges to sustainable agriculture worldwide. Biochar application to soil proves to be a suitable solution to these problems. Although the literature presents the pros and cons of biochar application, very little information is available on the impact of repeated application. In this study, we evaluate and discuss the effects of initial and reapplied biochar (both in rates of 0, 10, and 20 t ha⁻¹) combined with N fertilization (at doses of 0, 40, and 80 kg ha⁻¹) on soil properties and N₂O emission from Haplic Luvisol in the temperate climate zone (Slovakia). Results showed that biochar generally improved the soil properties such as soil pH_(KCl) (p ≤ 0.05; from acidic towards moderately acidic), soil organic carbon (p ≤ 0.05; an increase from 4% to over 100%), soil water availability (an increase from 1% to 15%), saturated hydraulic conductivity (an increase from 5% to 95%). The effects were more significant in the following cases: repeated rather than single biochar application, higher rather than lower biochar application rates, and higher rather than lower N fertilization levels. Initial and repeated biochar applications, leading to N₂O emissions reduction, can be related to increased soil pH_(KCl). Full article

(This article belongs to the Special Issue Biochar from Agricultural Residues for Sustainable Farming and Recultivation)

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17 pages, 2579 KiB

Open AccessEditor’s ChoiceArticle

Genetic Diversity of Soybeans (Glycine max (L.) Merr.) with Black Seed Coats and Green Cotyledons in Korean Germplasm

by Hyun Jo, Ji Yun Lee, Hyeontae Cho, Hong Jib Choi, Chang Ki Son, Jeong Suk Bae, Kristin Bilyeu, Jong Tae Song and Jeong-Dong Lee

Agronomy 2021, 11(3), 581; https://doi.org/10.3390/agronomy11030581 - 19 Mar 2021

Cited by 21 | Viewed by 5206

Abstract

Soybeans (Glycine max (L.) Merr.) with black seed coats and green cotyledons are rich in anthocyanins and chlorophylls known as functional nutrients, antioxidants and compounds with anticarcinogenic properties. Understanding the genetic diversity of germplasm is important to determine effective strategies for improving [...] Read more.

Soybeans (Glycine max (L.) Merr.) with black seed coats and green cotyledons are rich in anthocyanins and chlorophylls known as functional nutrients, antioxidants and compounds with anticarcinogenic properties. Understanding the genetic diversity of germplasm is important to determine effective strategies for improving the economic traits of these soybeans. We aimed to analyze the genetic diversity of 470 soybean accessions by 6K single nucleotide polymorphic loci to determine genetic architecture of the soybeans with black seed coats and green cotyledons. We found soybeans with black seed coats and green cotyledons showed narrow genetic variability in South Korea. The genotypic frequency of the d1d2 and psbM variants for green cotyledon indicated that soybean collections from Korea were intermingled with soybean accessions from Japan and China. Regarding the chlorophyll content, the nuclear gene variant pair d1d2 produced significantly higher chlorophyll a content than that of chloroplast genome psbM variants. Among the soybean accessions in this study, flower color plays an important role in the anthocyanin composition of seed coats. We provide 36 accessions as a core collection representing 99.5% of the genetic diversity from the total accessions used in this study to show potential as useful breeding materials for cultivars with black seed coats and green cotyledons. Full article

(This article belongs to the Special Issue Old Germplasm for New Needs: Managing Crop Genetic Resources)

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Graphical abstract

Graphical abstract
Full article ">Figure 1
Distribution of the genetic diversity of black soybean accessions with green cotyledon. Genetic diversity index (A), polymorphic information center (B), minor allele frequency (C), and heterozygosity (D) of 4459 SNPs across 467 black soybean collections with green cotyledon with three check cultivars. Full article ">Figure 2
Cluster analyses and a phylogenetic tree of 469 black soybean accessions with green cotyledon and a yellow cultivar. (A) ADMIXUTRE plot. Clustering from 2 to 5 of K value for the entire set of black soybean accessions with green cotyledon with yellow soybean. Each accession is showed to a vertical bar representing the proportion of the accession’s genome from clusters. (B) Principal components of SNP variation. Each PC1 and PC2 explained 26.0% and 14.4% of variance in the data. Cluster 1, cluster 2 and cluster 3 are shown by grey, orange, and blue color, respectively. Yellow, green, and light blue dot represented as Cheongja 3 (black soybean cultivar with green cotyledon), Cheongja (black soybean cultivar with green cotyledon) and Uram (yellow soybean), respectively (C) UPGMA (unweighted pair group method with arithmetic mean) phylogenetic tree of entire set of 470 accessions. Circle with light blue is yellow soybean, Uram and red circle consists of Cheongja and Cheongja 3. Full article ">Figure 3
Principal component and a phylogenetic tree of core subset containing 36 black soybean accessions with green cotyledon. (A) Distribution of three clusters in core subset (B) Principal components of SNP variation. Entire population and core subset are shown by blue and orange dots, respectively. Full article ">Figure 4
Distribution of d1d2 and psbM among black soybean accessions with green cotyledon in South Korea. Percentage of d1d2 genotype and psbM genotype are provided in each graph. (A) Total population. (B) Core set. (C) Cluster 1. (D) Cluster 2. (E) Cluster 3. Full article ">Figure 5
Chlorophyll content of d1d2 and psbM genotype. (A) Chlorophyll a, b and total content of d1d2 and psbM genotype. (B) Green cotyledon color without black seed coat for psbM and d1d2 genotype (C) Chlorophyll a/b ratio of d1d2 and psbM genotype. Statistical analysis was conducted using the Student’s t test (** p < 0.01). Bars indicate standard error. Full article ">Figure 6
Schematic for genes in the anthocyanin biosynthetic pathway with comparison of measured anthocyanin compositions and GWAS anlaysis. (A) the biosynthetic pathway of anthocyanins. Genes or corresponding enzymes are denoted with the capital letters of abbreviated names, as follows: Chalcone synthase (CHS, I locus); Flavonoid 3′-hydroxylase (F3′H, T locus); Flavonoid 3′,5′-hydroxylase (F3′5′H, W1 locus); Chalcone isomerase (CHI); Dihydroflavonol-4-reductase (DFR); Anthocyanidin synthase (ANS); Anthocyanidin reductase (ANR, O locus); Flavonoid 3-O-glucosyltransferase (UF3GT); Anthocyanin O-methyltransferase (AOMT). (B) Comparison of measured anthocyanin content of W1W1 and w1w1 genotype. Statistical analysis was conducted using the Student’s t test (** p < 0.01, ns; no significant). (C) GWAS anlaysis on mean of each anthocyanin and total content over three years. Delphinidin 3-O-glucoside (D3G); Cyanidin 3-O-glucoside (C3G); Petunidin 3-O-glucoside (P3G); Pelargonidin 3-O-glucoside (Pl3G); Peonidin 3-O-glucoside (Pn3G); Malvidin 3-O-glucosie (M3G). Full article ">

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