Agronomy

15 pages, 2721 KiB

Open AccessArticle

Supplementary Light Source Affects Growth and Development of Carnation ‘Dreambyul’ Cuttings

by Mengzhao Wang, Jie Xiao, Hao Wei and Byoung Ryong Jeong

Agronomy 2020, 10(8), 1217; https://doi.org/10.3390/agronomy10081217 - 18 Aug 2020

Cited by 9 | Viewed by 3040

Carnation (Dianthus caryophyllus L.) is a major floricultural crop, cultivated widely for cut flowers. This study was conducted to determine the optimal supplementary light source for the cutting propagation of carnation ‘Dreambyul’ cuttings. Terminal cuttings were propagated in a glasshouse with an [...] Read more.

Carnation (Dianthus caryophyllus L.) is a major floricultural crop, cultivated widely for cut flowers. This study was conducted to determine the optimal supplementary light source for the cutting propagation of carnation ‘Dreambyul’ cuttings. Terminal cuttings were propagated in a glasshouse with an average of 260 µmol·m⁻²·s⁻¹ photosynthetic photon flux density (PPFD) coming from the sun (the control), supplemented with one of three artificial light sources: mixed (red: blue: white = 6:1:1) light-emitting diodes (LED-mix), metal halide (MH) lamps, or high-pressure sodium (HPS) lamps. The supplementary light was provided from 7:00 to 17:00 h at 100 µmol·m⁻²·s⁻¹ PPFD during propagation. The cuttings were kept on a fogged bench in a glasshouse for 25 days with 24/15 °C day/night temperatures and 88% relative humidity. Compared with the control, better root formation was observed from cuttings grown under the supplementary lights after 10 days. After 25 days of propagation, MH significantly increased the root length, root number, root fresh and dry weights, and shoot biomass, shoot length, and shoot fresh and dry weights. The best root ball formation and the highest root activities were also found in cuttings propagated with supplementary MH light. Supplementary light increased the plant temperature, quantum yield, stomatal conductance, and the contents of chlorophyll, soluble proteins, and carbohydrates. Overall, the root formation and development of carnation ‘Dreambyul’ cuttings were significantly promoted by the three supplementary light sources. Of the three, MH was identified as the optimal supplementary light source. Full article

(This article belongs to the Section Horticultural and Floricultural Crops)

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13 pages, 1856 KiB

Open AccessArticle

Husk Leaf Senescence Characteristics of Spring Maize (Zea mays L.) Cultivated in Two Row Directions and Three Plant Spacings in Northeast China

by Shengqun Liu, Yan Gu, Xiaobo Wang, Xiangnan Li and Yang Wang

Agronomy 2020, 10(8), 1216; https://doi.org/10.3390/agronomy10081216 - 18 Aug 2020

Cited by 1 | Viewed by 2514

Abstract

Row direction and plant spacing influence crop senescence. An experiment was conducted to analyze the effect of row direction and plant spacing on the husk leaf senescence. Physiological indicators related to husk leaf senescence at days after silking (DAS) 12, 22, and 40 [...] Read more.

Row direction and plant spacing influence crop senescence. An experiment was conducted to analyze the effect of row direction and plant spacing on the husk leaf senescence. Physiological indicators related to husk leaf senescence at days after silking (DAS) 12, 22, and 40 were investigated under two row directions (east to west and south to north, abbreviated as EW and SN, respectively) and three plant patterns (single rows spaced at 65 cm, 40 cm twin rows spaced at 90 cm between the paired rows of narrow–wide rows, and 40 cm twin rows spaced at 160 cm between the paired rows of narrow–wide rows, abbreviated as SR, WN1, and WN2, respectively). Row direction affects the chlorophyll content and dehydration rate according to our results. Superoxide dismutase activity at DAS 22, catalase (CAT) activity at DS, and abscisic acid (ABA) concentrations at DAS 12, 22, and 40 were significantly affected by plant spacing. The CAT activities of WN1 and WN2 were significantly higher than those of SR, and WN2 had a lower ABA concentration than WN1 and SR. Our results suggest that row direction from SN and plant spacing from WN1 and WN2 were the suitable conditions for delaying the senescence of husk leaves of maize in the experimental site. Full article

(This article belongs to the Special Issue Biomass Crop Production, Management, and Ecophysiology)

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12 pages, 1030 KiB

Open AccessArticle

Effect of N Fertilization on the Content of Phenolic Compounds in Jerusalem Artichoke (Helianthus tuberosus L.) Tubers and Their Antioxidant Capacity

by Ryszard Amarowicz, Bożena Cwalina-Ambroziak, Michał A. Janiak and Bożena Bogucka

Agronomy 2020, 10(8), 1215; https://doi.org/10.3390/agronomy10081215 - 18 Aug 2020

Cited by 30 | Viewed by 4170

Abstract

Three cultivars of Jerusalem artichoke Albik, Rubik and Gute Gelbe were grown under different nitrogen fertilization regimens: 0, 80 and 120 kg N·ha⁻¹. Phenolic compounds were extracted from tubers using 80% (v/v) methanol. The total phenolics were determined with [...] Read more.

Three cultivars of Jerusalem artichoke Albik, Rubik and Gute Gelbe were grown under different nitrogen fertilization regimens: 0, 80 and 120 kg N·ha⁻¹. Phenolic compounds were extracted from tubers using 80% (v/v) methanol. The total phenolics were determined with the Folin–Ciocâlteu reagent and antioxidant activity was assessed using the ABTS (2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)), FRAP (ferric-reducing antioxidant power), and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays. The content of individual phenolic compounds was determined by HPLC. The effect of nitrogen fertilization on the total phenolics content was observed for the Albik cultivar. In the Rubik variety the lowest content was recorded at fertilization zero, and in the Gute Gelbe variety at this fertilization level the content of phenols was the highest. At fertilization 120 kg N·ha⁻¹, the highest ABTS test results were noted for all cultivars. For the Albik variety no effect of fertilization on the FRAP test results was noted; for the Rubik variety at zero nitrogen fertilization, the value for FRAP was the lowest, and it was the highest Gute Gelbe. The results of the DPPH test in the Gute Gelbe variety did not depend on the fertilization used. In the other two varieties, the lowest DPPH results were obtained at zero nitrogen regimen. Three main phenolic compounds were determined using HPLC. One of them was chlorogenic acid and the other two were derivatives of caffeic acid. The content of chlorogenic acid in tubers of the Gute Gelbe variety depended on nitrogen fertilization; the highest content of this compound was found in the case of fertilization zero. Statistical analysis showed a correlation between the content of phenolic compounds in tubers and their antioxidant potential. The results of this study suggest great potential for using Jerusalem artichoke tubers as a rich source of phenolic compounds with high antioxidant capacity. Full article

(This article belongs to the Special Issue Nitrogen Fertilization in Vegetable Crops)

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17 pages, 2634 KiB

Open AccessArticle

Effect of Biostimulants on Apple Quality at Harvest and After Storage

by Sebastian Soppelsa, Markus Kelderer, Raffaele Testolin, Damiano Zanotelli and Carlo Andreotti

Agronomy 2020, 10(8), 1214; https://doi.org/10.3390/agronomy10081214 - 18 Aug 2020

Cited by 12 | Viewed by 5062

Abstract

Nutritional unbalances, such as calcium deficiency at the fruit level, are generally the causative agent of post-harvest disorders in apples. Foliar application of Ca as calcium chloride is the current solution to increase Ca concentration in apples, even though the effectiveness of this [...] Read more.

Nutritional unbalances, such as calcium deficiency at the fruit level, are generally the causative agent of post-harvest disorders in apples. Foliar application of Ca as calcium chloride is the current solution to increase Ca concentration in apples, even though the effectiveness of this approach is often not satisfactory. In this research, we tested the efficacy of a combined application of Ca with selected biostimulants to improve apple quality and to reduce the incidence of storage disorders. The experiment was conducted in two “Jonathan” apple orchards that differed in management systems and characteristics. Tree canopies were sprayed with calcium chloride alone and in combination with a commercial product containing zinc and silicon or a seaweed extract. The seaweed extract increased apple quality by boosting the reddish coloration (+32% of color index) and by enhancing final anthocyanin concentration of fruit skin. Both biostimulants significantly reduced (by 20%) the incidence of the physiological disorder, known as “Jonathan spot”, after 160 days of storage. Increased concentration of nutrients (Ca, Zn, and Mn) in the skin of apples after biostimulant applications, together with changes of the phenolic profile during the storage, are discussed as the possible causes of the reduced fruit susceptibility to post-harvest disorders. Full article

(This article belongs to the Special Issue Biostimulants as Physiological Modulators of Crop Performance and Product Quality)

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18 pages, 648 KiB

Open AccessArticle

Short- and Long-Term Effects of Lime and Gypsum Applications on Acid Soils in a Water-Limited Environment: 1. Grain Yield Response and Nutrient Concentration

by Geoffrey C. Anderson, Shahab Pathan, James Easton, David J. M. Hall and Rajesh Sharma

Agronomy 2020, 10(8), 1213; https://doi.org/10.3390/agronomy10081213 - 18 Aug 2020

Cited by 15 | Viewed by 3262

Abstract

Surface (0–10 cm) and subsoil (soil layers below 10 cm) acidity and resulting aluminum (Al) toxicity reduce crop grain yields. In South Western Australia (SWA), these constraints affect 14.2 million hectares or 53% of the agricultural area. Both lime (L, CaCO₃) [...] Read more.

Surface (0–10 cm) and subsoil (soil layers below 10 cm) acidity and resulting aluminum (Al) toxicity reduce crop grain yields. In South Western Australia (SWA), these constraints affect 14.2 million hectares or 53% of the agricultural area. Both lime (L, CaCO₃) and gypsum (G, CaSO₄) application can decrease the toxic effect of Al, leading to an increase in crop grain yields. Within the region, it is unclear if G alone or the combined use of L and G has a role in alleviating soil acidity in SWA, due to low sulfate S (SO₄–S) sorption properties of the soil. We present results from three experiments located in the eastern wheatbelt of SWA, which examined the short-term (ST, 2 growing seasons), medium-term (MT, 3 growing seasons), and long-term (LT, 7 growing seasons over 10 years) effects of L and G on grain yield and plant nutrient concentrations. Despite the rapid leaching of SO₄–S and no self-liming impact, it was profitable to apply G, due to the significant ST grain yield responses. The grain yield response to G developed even following relatively dry years, but declined over time due to SO₄–S leaching. At the LT experimental site had received no previous L application, whereas, at the ST and MT sites, L had been applied by the grower over the previous 5–10 years. For the LT site, the most profitable treatment for wheat (Triticum aestivum L.) grain yield, was the combined application of 4 t L ha⁻¹ with 2 t G ha⁻¹. At this site, the 0–10 cm soil pH_CaCl2 was 4.6, and Al_CaCl2 was greater than 2.5 mg kg⁻¹ in the 10–30 cm soil layer. In contrast, at the ST and MT sites, the pH_CaCl2 of 0–10 cm soil layer was ≥5.5; it was only profitable to apply G to the MT site where the soil compaction constraint had been removed by deep ripping. The use of L increases soil pH_CaCl2, resulting in the improved availability of anions, phosphorus (P) in the LT and molybdenum (Mo) at all sampling times, but reduced availability of cations zinc (Zn) in the LT and manganese (Mn) at all sampling. The application of G reduced Mo concentrations, due to the high SO₄–S content of the soil. Full article

(This article belongs to the Special Issue Management of Soil Constraints to Improve Crop Performance in Water-Limited Environments)

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19 pages, 3360 KiB

Open AccessEditor’s ChoiceArticle

Regulation of Agronomic Traits, Nutrient Uptake, Osmolytes and Antioxidants of Maize as Influenced by Exogenous Potassium Silicate under Deficit Irrigation and Semiarid Conditions

by Mohamed F. M. Ibrahim, Gomaa Abd El-Samad, Hatem Ashour, Ahmed M. El-Sawy, Mohamed Hikal, Amr Elkelish, Hany Abd El-Gawad, Ahmed Abou El-Yazied, Wael N. Hozzein and Reham Farag

Agronomy 2020, 10(8), 1212; https://doi.org/10.3390/agronomy10081212 - 18 Aug 2020

Cited by 36 | Viewed by 3916

Abstract

Understanding the link between the protective role of potassium silicate (K₂SiO₃) against water shortage and the eventual grain yield of maize plants is still limited under semiarid conditions. Therefore, in this study, we provide insights into the underlying metabolic [...] Read more.

Understanding the link between the protective role of potassium silicate (K₂SiO₃) against water shortage and the eventual grain yield of maize plants is still limited under semiarid conditions. Therefore, in this study, we provide insights into the underlying metabolic responses, mineral nutrients uptake and some nonenzymatic and enzymatic antioxidants that may differ in maize plants as influenced by the foliar application of K₂SiO₃ (0, 1 and 2 mM) under three drip irrigation regimes (100, 75 and 50% of water requirements). Our results indicated that, generally, plants were affected by both moderate and severe deficit irrigation levels. Deficit irrigation decreased shoot dry weight, root dry weight, leaf area index (LAI), relative water content (RWC), N, P, K, Ca, Fe, Zn, carotenoids, grain yield and its parameters, while root/shoot ratio, malondialdehyde (MDA), proline, soluble sugars, ascorbic acid, soluble phenols, peroxidase (POD), catalase (CAT), polyphenol oxidase (PPO), and ascorbate peroxidase (APX) were improved. The foliar applications of K₂SiO₃ relatively alleviated water stress-induced damage. In this respect, the treatment of 2 mM K₂SiO₃ was more effective than others and could be recommended to mitigate the effect of deficit irrigation on maize plants. Moreover, correlation analysis revealed a close link between yield and the most studied traits. Full article

(This article belongs to the Special Issue Optimizing Plant Water Use Efficiency for a Sustainable Environment)

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13 pages, 2942 KiB

Open AccessEditor’s ChoiceArticle

The Effects of Alkaline Pretreatment on Agricultural Biomasses (Corn Cob and Sweet Sorghum Bagasse) and Their Hydrolysis by a Termite-Derived Enzyme Cocktail

by Mpho. S. Mafa, Samkelo Malgas, Abhishek Bhattacharya, Konanani Rashamuse and Brett I. Pletschke

Agronomy 2020, 10(8), 1211; https://doi.org/10.3390/agronomy10081211 - 18 Aug 2020

Cited by 29 | Viewed by 4770

Abstract

Sweet sorghum bagasse (SSB) and corncob (CC) have been identified as promising feedstocks for the production of second-generation biofuels and other value-added chemicals. In this study, lime (Ca(OH)₂) and NaOH pretreatment efficacy for decreasing recalcitrance from SSB and CC was investigated, [...] Read more.

Sweet sorghum bagasse (SSB) and corncob (CC) have been identified as promising feedstocks for the production of second-generation biofuels and other value-added chemicals. In this study, lime (Ca(OH)₂) and NaOH pretreatment efficacy for decreasing recalcitrance from SSB and CC was investigated, and subsequently, the pretreated biomass was subjected to the hydrolytic action of an in-house formulated holocellulolytic enzyme cocktail (HEC-H). Compositional analysis revealed that SSB contained 29.34% lignin, 17.75% cellulose and 16.28% hemicellulose, while CC consisted of 22.51% lignin, 23.58% cellulose and 33.34% hemicellulose. Alkaline pretreatment was more effective in pretreating CC biomass compared to the SSB biomass. Both Ca(OH)₂ and NaOH pretreatment removed lignin from the CC biomass, while only NaOH removed lignin from the SSB biomass. Biomass compositional analysis revealed that these agricultural feedstocks differed in their chemical composition because the CC biomass contained mainly hemicellulose (33–35%), while SSB biomass consisted mainly of cellulose (17–24%). The alkaline pretreated SSB and CC samples were subjected to the hydrolytic action of the holocellulolytic enzyme cocktail, formulated with termite derived multifunctional enzymes (referred to as MFE-5E, MFE-5H and MFE-45) and exoglucanase (Exg-D). The HEC-H hydrolysed NaOH pretreated SSB and CC more effectively than Ca(OH)₂ pretreated feedstocks, revealing that NaOH was a more effective pretreatment. In conclusion, the HEC-H cocktail efficiently hydrolysed alkaline pretreated agricultural feedstocks, particularly those which are hemicellulose- and amorphous cellulose-rich, such as CC, making it attractive for use in the bioconversion process in the biorefinery industry. Full article

(This article belongs to the Special Issue Pretreatment and Bioconversion of Crop Residues)

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15 pages, 1500 KiB

Open AccessArticle

Supporting Beneficial Insects for Agricultural Sustainability: The Role of Livestock-Integrated Organic and Cover Cropping to Enhance Ground Beetle (Carabidae) Communities

by Subodh Adhikari and Fabian D. Menalled

Agronomy 2020, 10(8), 1210; https://doi.org/10.3390/agronomy10081210 - 17 Aug 2020

Cited by 12 | Viewed by 5738

Abstract

Ground beetles (Carabidae) are beneficial insects providing ecosystem services by regulating insect pests and weed seeds. Despite several studies conducted on ground beetles worldwide, there is a lack of knowledge on how these insects are affected by differently managed organic systems (e.g., tillage-based [...] Read more.

Ground beetles (Carabidae) are beneficial insects providing ecosystem services by regulating insect pests and weed seeds. Despite several studies conducted on ground beetles worldwide, there is a lack of knowledge on how these insects are affected by differently managed organic systems (e.g., tillage-based versus grazed-based) compared to that of chemical-based no-tillage conventional cropping systems. In a 5-year (2013–2017) study, we assessed the ground beetle communities in cover crops and winter wheat (Triticum aestivium L.) in Montana, USA, with three contrasting cropping systems: a chemically managed no-tillage, a tillage-based organic, and a livestock-integrated organic with reduced tillage. The first three years (i.e., 2013–2015) corresponded to the transition to organic period, while the last two (i.e., 2016–2017) were conducted in United States Department of Agriculture (USDA) organic-certified tillage-based and livestock-integrated organic systems. The experiment was designed with three management systems across three blocks as the whole plot variable and 5-year rotation of crop phases as the subplot variable. Using pitfall traps, we sampled ground beetles across all cover crop and winter wheat subplots for five years (n = 450). The data were analyzed using mixed effects models and PERMANOVA and visualized with non-metric multidimensional scaling ordination. Our study indicated that organically managed farms, whether tilled or grazed, enhance activity density, species richness, diversity, and evenness of ground beetles in the dryland row crop productions. Also, irrespective of farming system, cover crops supported higher species richness, diversity, and evenness of ground beetles than winter wheat. The ground beetle communities were mostly similar during the transition to organic period. However, during the established organic phase, cropping systems acted as contrasting ecological filters and beetle communities became dissimilar. Cover cropping affected ground beetle communities positively not only in organically managed systems but also in chemical-based conventional systems. Our study provides evidence supporting the adoption of ecologically-based cropping systems such as crop-livestock integration, organic farming, and cover cropping to enhance beneficial insects and their pest-regulation services. Full article

(This article belongs to the Special Issue Agroecology and Organic Agriculture for Sustainable Crop Production)

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26 pages, 5418 KiB

Open AccessEditor’s ChoiceReview

Flavonoids in Agriculture: Chemistry and Roles in, Biotic and Abiotic Stress Responses, and Microbial Associations

by Ateeq Shah and Donald L. Smith

Agronomy 2020, 10(8), 1209; https://doi.org/10.3390/agronomy10081209 - 17 Aug 2020

Cited by 129 | Viewed by 11298

Abstract

The current world of climate change, global warming and a constantly changing environment have made life very stressful for living entities, which has driven the evolution of biochemical processes to cope with stressed environmental and ecological conditions. As climate change conditions continue to [...] Read more.

The current world of climate change, global warming and a constantly changing environment have made life very stressful for living entities, which has driven the evolution of biochemical processes to cope with stressed environmental and ecological conditions. As climate change conditions continue to develop, we anticipate more frequent occurrences of abiotic stresses such as drought, high temperature and salinity. Living plants, which are sessile beings, are more exposed to environmental extremes. However, plants are equipped with biosynthetic machinery operating to supply thousands of bio-compounds required for maintaining internal homeostasis. In addition to chemical coordination within a plant, these compounds have the potential to assist plants in tolerating, resisting and escaping biotic and abiotic stresses generated by the external environment. Among certain biosynthates, flavonoids are an important example of these stress mitigators. Flavonoids are secondary metabolites and biostimulants; they play a key role in plant growth by inducing resistance against certain biotic and abiotic stresses. In addition, the function of flavonoids as signal compounds to communicate with rhizosphere microbes is indispensable. In this review, the significance of flavonoids as biostimulants, stress mitigators, mediators of allelopathy and signaling compounds is discussed. The chemical nature and biosynthetic pathway of flavonoid production are also highlighted. Full article

(This article belongs to the Special Issue Application of Plant Growth Promoting Microorganism and Plant Growth Regulators in Agricultural Production and Research)

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15 pages, 1059 KiB

Open AccessArticle

Reducing Nitrate Accumulation and Fertilizer Use in Lettuce with Modified Intermittent Nutrient Film Technique (NFT) System

by Vincenzo Tabaglio, Roberta Boselli, Andrea Fiorini, Cristina Ganimede, Paolo Beccari, Stefano Santelli and Giuseppe Nervo

Agronomy 2020, 10(8), 1208; https://doi.org/10.3390/agronomy10081208 - 17 Aug 2020

Cited by 17 | Viewed by 4976

Abstract

Lettuce (Lactuca sativa L.) is a leading greenhouse-grown vegetable. However, nitrate (NO₃⁻) accumulation in leaves remains a major issue. The aims of this research were: (i) to test the modified intermittent Nutrient Film Technique (NFT) in the cultivation of [...] Read more.

Lettuce (Lactuca sativa L.) is a leading greenhouse-grown vegetable. However, nitrate (NO₃⁻) accumulation in leaves remains a major issue. The aims of this research were: (i) to test the modified intermittent Nutrient Film Technique (NFT) in the cultivation of soilless lettuce in which plants are grown on peat blocks in trays and supplied with an intermittent flow of nutrient solution, and (ii) to calibrate the fertilization scheme to increase yield performance, while keeping NO₃⁻ concentration under control. Two greenhouse trials were performed between autumn 2013 and spring 2014. Results showed that a 30-day cycle is the optimum duration in terms of fresh biomass yield, both for autumn and spring cultivation. Reducing N fertilization in the last cropping days never affected NO₃⁻ concentration in leaves during autumn trial, due to unfavourable growing conditions. Conversely, suspension of fertilization 2 days before harvest had a consistent effect during the spring trial, when NO₃⁻ concentration in leaves was highly reduced (from 20 to 36%) without yield penalties. Thus, suspending fertilization 2–4 days before harvesting in intermittent NFT may reduce, on average, NO₃⁻ accumulation by 29–58% and the fertilization rate by 7–16%, respectively. Yet, growing conditions are crucial to make this system effective. Full article

(This article belongs to the Special Issue Practice of Hydroponics in Vegetable Production)

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10 pages, 1264 KiB

Open AccessArticle

Virulence Screen of Beauveria Bassiana Isolates for Australian Carpophilus (Coleoptera: Nitidulidae) Beetle Biocontrol

by William Boston, Diana Leemon and John Paul Cunningham

Agronomy 2020, 10(8), 1207; https://doi.org/10.3390/agronomy10081207 - 17 Aug 2020

Cited by 8 | Viewed by 4019

Abstract

Carpophilus beetles are serious pests of Australian fruit and nut crops, causing significant damage through adult and larval feeding and vectoring plant diseases. Six strains of the entomopathogenic fungus Beauveria bassiana ((Balsamo) Vuillemin; Hypocreales: Cordycipitaceae), isolated from a range of hosts in Australia, [...] Read more.

Carpophilus beetles are serious pests of Australian fruit and nut crops, causing significant damage through adult and larval feeding and vectoring plant diseases. Six strains of the entomopathogenic fungus Beauveria bassiana ((Balsamo) Vuillemin; Hypocreales: Cordycipitaceae), isolated from a range of hosts in Australia, together with one commercial strain, were screened for virulence to adult and larval stages of Carpophilus attacking stone fruits (C. davidsoni (Dobson)) and almonds (C. truncatus (Murray)) under laboratory conditions. The two species differed significantly in their susceptibility to the B. bassiana isolates. In the adult beetle assay, C. truncatus had a maximum Abbott’s control corrected mortality of 19% when treated with the most effective isolate, B54, compared to 52% for C.davidsoni. In larval bioassays, mortality rates for the two species were generally higher than adults: four isolates caused greater than 80% mortality in C. davidsoni; while only one isolate was considered effective against C. truncatus (causing 73% mortality), all other isolates caused less than 40% mortality. The results indicate promising potential for B. bassiana to be applied as a biopesticide as part of an integrated pest management strategy, which might take the form of a soil application against larvae or an autodissemination program using adult beetles. Full article

(This article belongs to the Special Issue Pest Biocontrol Strategies in Agroecological Management of Cultivated Ecosystems)

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19 pages, 5120 KiB

Open AccessArticle

High-Throughput Ground Cover Classification of Perennial Ryegrass (Lolium Perenne L.) for the Estimation of Persistence in Pasture Breeding

by Chinthaka Jayasinghe, Pieter Badenhorst, Joe Jacobs, German Spangenberg and Kevin Smith

Agronomy 2020, 10(8), 1206; https://doi.org/10.3390/agronomy10081206 - 17 Aug 2020

Cited by 3 | Viewed by 3249

Abstract

Perennial ryegrass (Lolium perenne L.) is one of the most important forage grass species in temperate regions of Australia and New Zealand. However, it can have poor persistence due to a low tolerance to both abiotic and biotic stresses. A major challenge [...] Read more.

Perennial ryegrass (Lolium perenne L.) is one of the most important forage grass species in temperate regions of Australia and New Zealand. However, it can have poor persistence due to a low tolerance to both abiotic and biotic stresses. A major challenge in measuring persistence in pasture breeding is that the assessment of pasture survival depends on ranking populations based on manual ground cover estimation. Ground cover measurements may include senescent and living tissues and can be measured as percentages or fractional units. The amount of senescent pasture present in a sward may indicate changes in plant growth, development, and resistance to abiotic and biotic stresses. The existing tools to estimate perennial ryegrass ground cover are not sensitive enough to discriminate senescent ryegrass from soil. This study aimed to develop a more precise sensor-based phenomic method to discriminate senescent pasture from soil. Ground-based RGB images, airborne multispectral images, ground-based hyperspectral data, and ground truth samples were taken from 54 perennial ryegrass plots three years after sowing. Software packages and machine learning scripts were used to develop a pipeline for high-throughput data extraction from sensor-based platforms. Estimates from the high-throughput pipeline were positively correlated with the ground truth data (p < 0.05). Based on the findings of this study, we conclude that the RGB-based high-throughput approach offers a precision tool to assess perennial ryegrass persistence in pasture breeding programs. Improvements in the spatial resolution of hyperspectral and multispectral techniques would then be used for persistence estimation in mixed swards and other monocultures. Full article

(This article belongs to the Special Issue Applied Plant Breeding and Quantitative Genetics Research to Improve Forage and Turf Plants)

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18 pages, 3446 KiB

Open AccessArticle

Formosolv Pretreatment to Fractionate Paulownia Wood Following a Biorefinery Approach: Isolation and Characterization of the Lignin Fraction

by Elena Domínguez, Pablo G. del Río, Aloia Romaní, Gil Garrote, Patricia Gullón and Alberto de Vega

Agronomy 2020, 10(8), 1205; https://doi.org/10.3390/agronomy10081205 - 17 Aug 2020

Cited by 9 | Viewed by 3050

Abstract

Paulownia is a rapid-growth tree with a high biomass production rate per year and low demand of water, which make it very suitable for intercropping systems, as it protects the crops from adverse climatic conditions, benefiting the harvest yields. Moreover, these characteristics make [...] Read more.

Paulownia is a rapid-growth tree with a high biomass production rate per year and low demand of water, which make it very suitable for intercropping systems, as it protects the crops from adverse climatic conditions, benefiting the harvest yields. Moreover, these characteristics make Paulownia a suitable raw material able to be fractionated in an integrated biorefinery scheme to obtain multiple products using a cascade conversion approach. Different delignification pretreatments of biomass have been purposed as a first stage of a lignocellulosic biorefinery. In this study, the formosolv delignification of Paulownia wood was investigated using a second order face-centered factorial design to assess the effects of the independent variables (concentrations of formic and hydrochloric acids and reaction time) on the fractionation of Paulownia wood. The maximum delignification achieved in this study (78.5%) was obtained under following conditions: 60 min, and 95% and 0.05% formic and hydrochloric acid, respectively. In addition, the remained solid phases were analyzed to determine their cellulose content and cooking liquors were also chemically analyzed and characterized. Finally, the recovered lignin by precipitation from formosolv liquor and the pristine lignin (milled wood lignin) in Paulownia wood were characterized and compared by the following techniques FTIR, NMR, high-performance size-exclusion chromatography (HPSEC) and TGA. This complete characterization allowed verifying the capacity of the formosolv process to act on the lignin, causing changes in its structure, which included both phenomena of depolymerization and condensation. Full article

(This article belongs to the Special Issue Pretreatment and Bioconversion of Crop Residues)

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15 pages, 1827 KiB

Open AccessArticle

Identification of Non-Pleiotropic Loci in Flowering and Maturity Control in Soybean

by Eric J. Sedivy, Abraham Akpertey, Angela Vela, Sandra Abadir, Awais Khan and Yoshie Hanzawa

Agronomy 2020, 10(8), 1204; https://doi.org/10.3390/agronomy10081204 - 17 Aug 2020

Cited by 3 | Viewed by 2659

Abstract

Pleiotropy is considered to have a significant impact on multi-trait evolution, but its roles in the evolution of domestication-related traits in crop species have been unclear. In soybean, several known quantitative trait loci (QTL) controlling maturity, called the maturity loci, are known to [...] Read more.

Pleiotropy is considered to have a significant impact on multi-trait evolution, but its roles in the evolution of domestication-related traits in crop species have been unclear. In soybean, several known quantitative trait loci (QTL) controlling maturity, called the maturity loci, are known to have major effects on both flowering and maturity in a highly correlated pleiotropic manner. Aiming at the identification of non-pleiotropic QTLs that independently control flowering and maturity and dissecting the effects of pleiotropy in these important agronomic traits, we conducted a QTL mapping experiment by creating a population from a cross between domesticated soybean G. max and its wild ancestor G. soja that underwent stringent selection for non-pleiotropy in flowering and maturity. Our QTL mapping analyses using the experimental population revealed novel loci that acted in a non-pleiotropic manner: R1-1 controlled primarily flowering and R8-1 and R8-2 controlled maturity, while R1-1 overlapped with QTL, affecting other agronomic traits. Our results suggest that pleiotropy in flowering and maturity can be genetically separated, while artificial selection during soybean domestication and diversification may have favored pleiotropic loci such as E loci that control both flowering and maturity. The non-pleiotropic loci identified in this study will help to identify valuable novel genes to optimize soybean’s life history traits and to improve soybean’s yield potential under diverse environments and cultivation schemes. Full article

(This article belongs to the Special Issue Genetics, Genomics, and Breeding of Legume Crops)

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18 pages, 1811 KiB

Open AccessArticle

Plant Yield Efficiency by Homeostasis as Selection Tool at Ultra-Low Density. A Comparative Study with Common Stability Measures in Maize

by Evaggelia Sinapidou, Chrysanthi Pankou, Fotakis Gekas, Iosif Sistanis, Constantinos Tzantarmas, Maria Tokamani, Ioannis Mylonas, Ioannis Papadopoulos, Anastasia Kargiotidou, Elissavet Ninou, Fokion Papathanasiou, Raphael Sandaltzopoulos and Ioannis S. Tokatlidis

Agronomy 2020, 10(8), 1203; https://doi.org/10.3390/agronomy10081203 - 16 Aug 2020

Cited by 4 | Viewed by 3274

Abstract

The study pertains to field experimentation testing seven maize (Zea mays L.) hybrids at four densities, across five locations under normal (NIR) and low-input (LIR) regimes. The main objective was to assess the prognostic value of plant yield efficiency by homeostasis (PYEH) [...] Read more.

The study pertains to field experimentation testing seven maize (Zea mays L.) hybrids at four densities, across five locations under normal (NIR) and low-input (LIR) regimes. The main objective was to assess the prognostic value of plant yield efficiency by homeostasis (PYEH) for breeding purposes at ultra-low plant density to predict hybrid yield potential and stability. PYEH comprises plant yield efficiency (PYE) that reflects the ability of individual plants to exploit resources, and plant yield homeostasis (PYH) that indicates the crop’s ability to evade acquired plant-to-plant variability. The same hybrids were also evaluated for stability by commonly used parametric and non-parametric statistics based on data at low (LCD) and high crop densities (HCD). Hybrid stability focused on potential yield loss due to erratic optimum density (OD). Most methods produced conflicting results regarding hybrid ranking for yield and stability especially at LCD. In contrast, PYEH consistently highlighted high-yielding and stable hybrids, potentially able to reach the attainable crop yield (ACY) inter-seasonally irrespective of crop spacing. Low density is common practice under resource-deficit conditions, so crop adaptation to crop spacing is a viable option to overcome erratic OD that constitutes a root source of crop instability in rainfed maize. The results were further supportive of breeding at ultra-low density to facilitate the identification and selection of superior genotypes, since such conditions promote phenotypic expression and differentiation, and ensure repeatability across diverse environments. Full article

(This article belongs to the Special Issue Genotype× Environment Interactions in Crop Breeding)

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11 pages, 241 KiB

Open AccessArticle

Effect of Plant Biostimulants on Macronutrient Content in Early Crop Potato Tubers

by Tomasz Dziugieł and Wanda Wadas

Agronomy 2020, 10(8), 1202; https://doi.org/10.3390/agronomy10081202 - 16 Aug 2020

Cited by 7 | Viewed by 2932

Abstract

This paper analyzes the effects of the foliar application of the seaweed extracts Bio-algeen S90 (Ascophyllum nodosum) and Kelpak SL (Ecklonia maxima), as well as the humic and fulvic acids in HumiPlant (leonardite extract) on the macronutrient content in [...] Read more.

This paper analyzes the effects of the foliar application of the seaweed extracts Bio-algeen S90 (Ascophyllum nodosum) and Kelpak SL (Ecklonia maxima), as well as the humic and fulvic acids in HumiPlant (leonardite extract) on the macronutrient content in tubers of very early potato cultivars (‘Denar’, ‘Lord’, ‘Miłek’) and their ionic ratios. The field experiment was carried out in central-eastern Poland over three growing seasons, using Haplic Luvisol. The biostimulants were applied according to the manufacturers’ recommendations. Potatoes were harvested 75 days after planting. The use of biostimulants increased potassium (K) content in tubers, on average, by 1.26 g∙kg⁻¹ of dry matter compared with the untreated control tubers. Bio-algeen S90 did not affect the phosphorus (P) content in tubers, whereas Kelpak SL and HumiPlant reduced the phosphorus content, on average, by 0.063 g∙kg⁻¹ of dry matter. The biostimulants did not affect calcium (Ca), magnesium (Mg), or sodium (Na) content in tubers. The use of biostimulants resulted in an increase in the mass ratios of K⁺:Ca²⁺, K⁺:Mg²⁺, and (K⁺ + Na⁺):(Ca²⁺ + Mg²⁺) in early crop potato tubers, compared with the untreated control tubers, but did not affect the mass ratios of Na⁺:Ca²⁺ and Na⁺:Mg²⁺ or the mass ratio of Ca:P. The macronutrient content in early crop potato tubers and their ionic ratios depended on the cultivar and environment conditions. Full article

13 pages, 260 KiB

Open AccessArticle

The Influence of Red Light (RL) and Effective Microorganism (EM) Application on Soil Properties, Yield, and Quality in Wheat Cultivation

by Mariusz Szymanek, Agata Dziwulska-Hunek, Janusz Zarajczyk, Sławomir Michałek and Wojciech Tanaś

Agronomy 2020, 10(8), 1201; https://doi.org/10.3390/agronomy10081201 - 15 Aug 2020

Cited by 11 | Viewed by 3095

Abstract

The aim of the study was to determine the impact of red light (RL) and effective microorganisms (EMs) on the wheat yield of grain and straw, as well as the quality (protein, carbohydrates, gluten, index of sedimentation (SDS index), germination capacity). Moreover, the [...] Read more.

The aim of the study was to determine the impact of red light (RL) and effective microorganisms (EMs) on the wheat yield of grain and straw, as well as the quality (protein, carbohydrates, gluten, index of sedimentation (SDS index), germination capacity). Moreover, the experiments measured the granulometric composition and pH of soil, as well as its content of microelements and major nutrients, including heavy metals. The field experiment was conducted in 2017, 2018, and 2019 at the experimental station (Felin) of the University of Life Sciences in Lublin (Poland). The best results in terms of overall yield, protein content, and SDS index were obtained after the red light treatment (RL). The three-year application of effective microorganisms (EMs) in the soil had a positive impact, relative to the control, on the grain yield, straw yield, starch, SDS index, and germination capacity. A slight decrease was observed in terms of the protein content. After the application of effective microorganisms (EMs) in soil, changes were observed in the soil’s granulometric composition, pH, humus, and microelements. Full article

(This article belongs to the Special Issue Effects of Biostimulants and Bioeffectors on Plant Growth)

21 pages, 3693 KiB

Open AccessArticle

Productive and Physiological Response of Organic Potato Grown under Highly Calcareous Soils to Fertilization and Mycorrhization Management

by Sara Lombardo, Cristina Abbate, Gaetano Pandino, Bruno Parisi, Aurelio Scavo and Giovanni Mauromicale

Agronomy 2020, 10(8), 1200; https://doi.org/10.3390/agronomy10081200 - 14 Aug 2020

Cited by 14 | Viewed by 3459

Abstract

The enhancement of the actual low yields is the most important challenge regarding organic farming management. In this view, a valid tool may arise by the improvement of fertilization management and efficiency. In this regard, arbuscular mycorrhizal fungi (AMF) can play an important [...] Read more.

The enhancement of the actual low yields is the most important challenge regarding organic farming management. In this view, a valid tool may arise by the improvement of fertilization management and efficiency. In this regard, arbuscular mycorrhizal fungi (AMF) can play an important role, especially in low fertility soils such as calcareous ones, through a better nutrient uptake and by alleviating abiotic stresses. A replicated-space experiment was carried out to investigate the role of mycorrhizal-based inoculants combined with full or halved fertilizer doses on yield and physiological traits of three early potato cultivars organically grown in highly calcareous and alkaline soils. The results indicate that AMF symbiosis ameliorated, in comparison to the not-inoculated plants, the potato tolerance to limestone stress by enhancing the potential quantum efficiency of photosystem II (F_v/F₀) and plant gas-exchange parameters (photosynthesis rate and stomatal conductance). Moreover, a significant improvement of marketable yield (+25%) was observed, mainly due to an increase of the number of tubers plant⁻¹ (+21%) and, to a lesser extent, of average tuber weight (+10%). The AMF efficiency was higher applying halved fertilizer doses and in the location where soil conditions were unfavourable for potato growth. Moreover, the qRT-PCR highlighted that AMF colonization was similar in each location, demonstrating their tolerance to limestone, alkalinity and P stresses. These findings outlined that AMF are good candidate to bio-ameliorate calcareous soils and are very useful for improving potato yields under organic farming, limiting external fertilizers supply and environmental pollution. Full article

(This article belongs to the Special Issue Herbaceous Field Crops Cultivation)

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15 pages, 3323 KiB

Open AccessArticle

Effects of Morphological and Anatomical Characteristics of Banana Crown Vascular Bundles on Cutting Mechanical Properties Using Multiple Imaging Methods

by Lei Zhao, Haijun Yang, Heng Xie, Jieli Duan, Mohui Jin, Han Fu, Jie Guo, Zeyu Xu, Tingting Jiang and Zhou Yang

Agronomy 2020, 10(8), 1199; https://doi.org/10.3390/agronomy10081199 - 14 Aug 2020

Cited by 5 | Viewed by 4786

Abstract

To obtain the appropriate mechanized cutting region for banana dehanding, the methods of X-ray Computed Tomography (CT), Paraffin-embedded tissue section, and scanning electron microscopy (SEM) were adopted to observe the morphological and anatomical characteristics of vascular bundles of the banana crown. The results [...] Read more.

To obtain the appropriate mechanized cutting region for banana dehanding, the methods of X-ray Computed Tomography (CT), Paraffin-embedded tissue section, and scanning electron microscopy (SEM) were adopted to observe the morphological and anatomical characteristics of vascular bundles of the banana crown. The results indicated that the crown can be divided into three regions, viz., the central stalk–crown transition region (CSCTR), the crown expansion region (CER), and the crown–finger transition region (CFTR). According to the obtained characteristics, the cutting mechanical properties are found to be affected by the relative angle between the vascular bundle and cutter (RAVBC) and the vascular bundle density. In CSCTR, due to the opposite change of RAVBC and density, the cutting mechanical properties become unstable and the cutting energy decreases gradually from 4.30 J to 2.57 J. While in CER, the cutting mechanical properties tend to be stable, and the cutting energy varies in a small range (2.83–2.92 J), owing to the small changes of RAVBC and density. When the vascular bundles cross from the CER to CFTR, the cutting energy increases with the increase of RAVBC and density, which varies from 3.37 to 4.84 J. Accordingly, the appropriate cutting region for dehanding, which can reduce the energy consumption and improve the cutting efficiency, is ascertained to be between CSCTR and CER. Full article

(This article belongs to the Section Agricultural Biosystem and Biological Engineering)

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25 pages, 383 KiB

Open AccessArticle

Efficiencies of Heterotic Grouping Methods for Classifying Early Maturing Maize Inbred Lines

by Oyeboade Adebiyi Oyetunde, Baffour Badu-Apraku, Omolayo Johnson Ariyo and Christopher Olusanya Alake

Agronomy 2020, 10(8), 1198; https://doi.org/10.3390/agronomy10081198 - 14 Aug 2020

Cited by 16 | Viewed by 4612

Abstract

The success of a hybrid breeding program is dependent on available heterotic patterns for exploitation of grain-yield heterosis. The efficiency of the assignment of germplasm lines into heterotic groups is a prerequisite for obtaining useful heterotic patterns among germplasm lines. A total of [...] Read more.

The success of a hybrid breeding program is dependent on available heterotic patterns for exploitation of grain-yield heterosis. The efficiency of the assignment of germplasm lines into heterotic groups is a prerequisite for obtaining useful heterotic patterns among germplasm lines. A total of 256 maize hybrids, comprising 244 top crosses, six diallel cross hybrids, and six checks, were grown under Striga infestation, drought, and optimal conditions, from 2015 to 2017. The study determined the combining abilities of the parental inbreds, classified the inbreds into heterotic groups, and compared the efficiencies of the following four grouping methods for classifying the inbreds: specific combining ability (SCA) effect of grain yield; general combining ability (GCA) effects of multiple traits (HGCAMT); SCA and GCA (HSGCA) for yield; and single nucleotide polymorphism-based genetic distance (SNP-based genetic distance (GD)). Significant GCA and/or SCA mean squares were revealed for most measured traits in all test environments. Sums of squares (SS) due to GCA were higher than SCA SS for measured traits in all test environments. The HSGCA, SCA, and SNP-based GD methods identified four heterotic groups, whereas the HGCAMT identified three groups, in all environments. The additive gene effect was preponderant in the inheritance of most measured traits. The efficiencies of the grouping methods varied with the test environments. The HSGCA and SCA methods were the most efficient for grouping in all test conditions. For practical breeding purposes, the HGCAMT and HSGCA methods were recommended under Striga infestation and drought, respectively. The heterotic patterns, which were revealed in this study, were effective for planning hybridization schemes for developing high-yielding, Striga-tolerant/resistant, and drought-tolerant maize hybrids for stressful environments. Full article

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

17 pages, 5104 KiB

Open AccessArticle

Genome-Wide Identification and Expression Analysis of MIKC-Type MADS-Box Gene Family in Punica granatum L.

by Yujie Zhao, Honglian Zhao, Yuying Wang, Xinhui Zhang, Xueqing Zhao and Zhaohe Yuan

Agronomy 2020, 10(8), 1197; https://doi.org/10.3390/agronomy10081197 - 14 Aug 2020

Cited by 15 | Viewed by 2784

Abstract

MADS-box is a critical transcription factor regulating the development of floral organs and plays essential roles in the growth and development of floral transformation, flower meristem determination, the development of male and female gametophytes, and fruit development. In this study, 36 MIKC-type MADS-box [...] Read more.

MADS-box is a critical transcription factor regulating the development of floral organs and plays essential roles in the growth and development of floral transformation, flower meristem determination, the development of male and female gametophytes, and fruit development. In this study, 36 MIKC-type MADS-box genes were identified in the ‘Taishanhong’ pomegranate genome. By utilizing phylogenetic analysis, 36 genes were divided into 14 subfamilies. Bioinformatics methods were used to analyze the gene structure, conserved motifs, cis-acting elements, and the protein interaction networks of the MIKC-type MADS-box family members in pomegranate, and their expressions pattern in different tissues of pomegranate were analyzed. Tissue-specific expression analysis revealed that the E-class genes (PgMADS03, PgMADS21, and PgMADS27) were highly expressed in floral tissues, while PgMADS29 was not expressed in all tissues, indicating that the functions of the E-class genes were differentiated. PgMADS15 of the C/D-class was the key gene in the development network of pomegranate flower organs, suggesting that PgMADS15 might play an essential role in the peel and inner seed coat development of pomegranate. The results in this study will provide a reference for the classification, cloning, and functional research of pomegranate MADS-box genes. Full article

(This article belongs to the Special Issue Domestication and Transcription Factors Related to Important Traits in Horticultural Crops)

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16 pages, 2447 KiB

Open AccessArticle

Comparison of Two Inoculation Methods of Endophytic Bacteria to Enhance Phytodegradation Efficacy of an Aged Petroleum Hydrocarbons Polluted Soil

by Małgorzata Pawlik, Tomasz Płociniczak, Sofie Thijs, Isabel Pintelon, Jaco Vangronsveld and Zofia Piotrowska-Seget

Agronomy 2020, 10(8), 1196; https://doi.org/10.3390/agronomy10081196 - 14 Aug 2020

Cited by 16 | Viewed by 3716

Abstract

Endophyte-enhanced phytodegradation is a promising technology to clean up polluted soils. To improve the success rate of this nature-based remediation approach, it is important to advance the inoculation method as this has been shown to strongly affect the final outcome. However, studies evaluating [...] Read more.

Endophyte-enhanced phytodegradation is a promising technology to clean up polluted soils. To improve the success rate of this nature-based remediation approach, it is important to advance the inoculation method as this has been shown to strongly affect the final outcome. However, studies evaluating inoculation strategies and their effect on hydrocarbon degradation are limited. This study aims to investigate two different manners of endophyte inoculation in Lolium perenne growing in an aged petroleum hydrocarbon polluted soil: (1) direct soil inoculation (SI), and (2) pre-inoculation of the caryopses followed by soil inoculation (PI). Different endophytic bacterial strains, Rhodococcus erythropolis 5WK and Rhizobium sp. 10WK, were applied individually as well as in combination. Depending on the method of inoculation, the petroleum hydrocarbon (PHC) degradation potential was significantly different. The highest PHC removal was achieved after pre-inoculation of ryegrass caryopses with a consortium of both bacterial strains. Moreover, both strains established in the aged-polluted soil and could also colonize the roots and shoots of L. perenne. Importantly, used endophytes showed the selective colonization of the environment compartments. Our findings show that the method of inoculation determines the efficiency of the phytodegradation process, especially the rate of PHC degradation. This study provides valuable information for choosing the most cost-effective and beneficial means to optimize phytodegradation. Full article

(This article belongs to the Special Issue Agronomic Approaches for Remediation of Contaminated Soils)

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14 pages, 3415 KiB

Open AccessArticle

How Film Mulch Increases the Corn Yield by Improving the Soil Moisture and Temperature in the Early Growing Period in a Cool, Semi-Arid Area

by Meng Kong, Yu Jia, Yan-Jie Gu, Cheng-Long Han, Xin Song, Xiao-Yan Shi, Kadambot H.M. Siddique, Pandi Zdruli, Feng Zhang and Feng-Min Li

Agronomy 2020, 10(8), 1195; https://doi.org/10.3390/agronomy10081195 - 14 Aug 2020

Cited by 7 | Viewed by 2662

Abstract

Film mulch increases the crop grain yield via topsoil moisture and temperature improvement in cool, semi-arid areas, but little is known about the role of the hydrological and thermic relationship between early and later crop growth seasons in the improving grain yield. We [...] Read more.

Film mulch increases the crop grain yield via topsoil moisture and temperature improvement in cool, semi-arid areas, but little is known about the role of the hydrological and thermic relationship between early and later crop growth seasons in the improving grain yield. We conducted a field experiment to compare polyethylene film mulching (PM) with no mulching (CK) in 2014 and 2015 on the semi-arid Loess Plateau of China. Compared to CK, PM decreased evapotranspiration before the twelve-leaf stage (V12), but increased evapotranspiration after the V12 stage, and significantly increased the topsoil temperature before the six-leaf stage (V6) and the accumulation of soil growing degree days. Corn plants with PM treatment reached the V6 stage earlier, significantly enhancing the contemporary dry matter accumulation. The harvest index, 100-grain weight, and grain yield significantly increased in PM relative to CK in both years. The growing period to the whole growing season evapotranspiration ratio had a negative correlation with the grain yield before the V12 stage, but a positive correlation after the V12 stage. The grain yield had a negative correlation with the air growing degree days (GDD_air) before the V6 stage, but positive correlation from silking to harvest. Conclusively, film mulch promoted the early development of maize via an increased soil temperature before the V6 stage, saved soil water before the V12 stage, resulted in a longer grain-filling period, and increased the GDD_air and evapotranspiration during the grain-filling period, which is key to increasing the maize yield. Full article

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17 pages, 2368 KiB

Open AccessArticle

Morphological and Physiological Traits that Explain Yield Response to Drought Stress in Miscanthus

by Marta Malinowska, Iain Donnison and Paul Robson

Agronomy 2020, 10(8), 1194; https://doi.org/10.3390/agronomy10081194 - 14 Aug 2020

Cited by 20 | Viewed by 3554

Abstract

Miscanthus is a high yielding perennial grass capable of high biomass yields with low inputs. Traits associated with yield have been identified in miscanthus, but less is known about the traits associated with sustaining biomass production under drought stress. The commercial hybrid M. [...] Read more.

Miscanthus is a high yielding perennial grass capable of high biomass yields with low inputs. Traits associated with yield have been identified in miscanthus, but less is known about the traits associated with sustaining biomass production under drought stress. The commercial hybrid M. × giganteus and high yielding examples from the parental species M. sinensis and M. sacchariflorus were grown under well-watered and moderate drought conditions. Growth, morphology, physiology and phenotypic plasticity were analyzed. Functional data were parameterized and a matrix of traits examined for associations with yield, genotype and drought treatment. Phenotypic plasticity was determined, indexes were then calculated to determine the plasticity of trait responses. All genotypes assessed responded to moderate drought stress, and genotypic differences in yield decreased under drought. Genotypes with low tolerance exhibited greater plasticity than highly drought tolerant M. sinensis. In well-watered plants variance in yield was explained by a relatively simple empirical model including stem length and stem number, whereas under drought a more complex model was needed including the addition of leaf area and stomatal conductance data. This knowledge can help us to define ideotypes for drought tolerance and develop miscanthus varieties that sustain high yields across a range of environmental conditions. Full article

(This article belongs to the Collection Towards Sustainable Intensification of Crop Production—Yield Gaps and Water Use Efficiency in Farming Systems)

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16 pages, 2398 KiB

Open AccessArticle

Genetic Diversity and Population Structure of Brachiaria (syn. Urochloa) Ecotypes from Uganda

by Clementine Namazzi, Julius Pyton Sserumaga, Swidiq Mugerwa, Martina Kyalo, Collins Mutai, Robert Mwesigwa, Appolinaire Djikeng and Sita Ghimire

Agronomy 2020, 10(8), 1193; https://doi.org/10.3390/agronomy10081193 - 14 Aug 2020

Cited by 8 | Viewed by 3405

Abstract

Brachiaria (syn. Urochloa) grass is an important tropical forage of African origin that supports millions of livestock and wildlife in the tropics. Overgrazing, conversion of grasslands for crop production and non-agricultural uses, and the introduction of improved forages have threatened the natural [...] Read more.

Brachiaria (syn. Urochloa) grass is an important tropical forage of African origin that supports millions of livestock and wildlife in the tropics. Overgrazing, conversion of grasslands for crop production and non-agricultural uses, and the introduction of improved forages have threatened the natural diversity of Brachiaria grass in Uganda. This study established a national collection of Brachiaria ecotypes in Uganda and analyzed them for genetic diversity and population structure using 24 simple sequence repeats (SSR) markers. These markers had a high discriminating ability with an average polymorphism information content (PIC) of 0.89 and detected 584 alleles in 99 ecotypes. Analysis of molecular variance revealed a high within populations variance (98%) indicating a high gene exchange or low genetic differentiation (PhiPT = 00.016) among the ecotype populations. The Bayesian model based clustering algorithm showed three allelic pools in Ugandan ecotypes. The principal component analysis (PCA) of ecotypes, and Neighbor-joining (NJ) tree of ecotypes and six commercial cultivars showed three main groups with variable membership coefficients. About 95% of ecotype pairs had Rogers’ genetic distance above 0.75, suggesting most of them were distantly related. This study confirms the high value of these ecotypes in Brachiaria grass conservation and improvement programs in Uganda and elsewhere. Full article

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14 pages, 3811 KiB

Open AccessEditor’s ChoiceArticle

Water-Soluble Carbon Nanoparticles Improve Seed Germination and Post-Germination Growth of Lettuce under Salinity Stress

by Hanna Baz, Matthew Creech, Jianjun Chen, Haijun Gong, Kent Bradford and Heqiang Huo

Agronomy 2020, 10(8), 1192; https://doi.org/10.3390/agronomy10081192 - 13 Aug 2020

Cited by 57 | Viewed by 5366

Abstract

Seed germination is a critical developmental phase for seedling establishment and crop production. Increasing salinity stress associated with climatic change can pose a challenge for seed germination and stand establishment of many crops including lettuce. Here, we show that water soluble carbon nanoparticles [...] Read more.

Seed germination is a critical developmental phase for seedling establishment and crop production. Increasing salinity stress associated with climatic change can pose a challenge for seed germination and stand establishment of many crops including lettuce. Here, we show that water soluble carbon nanoparticles (CNPs) can significantly promote seed germination without affecting seedling growth. Twenty-seven varieties of lettuce (Lactuca sativa) were screened for sensitivity to germination in 150 and 200 mM NaCl, and six salt-sensitive varieties (Little Gem, Parris Island, Breen, Butter Crunch, Muir, and Jericho) were selected and primed with 0.3% soluble carbon nanoparticles. Pretreatment with CNPs significantly improved seed germination under 150 mM NaCl and high temperature. CNP treatment slightly inhibited the elongation of primary roots but promoted lateral root growth and accumulation of chlorophyll content of seedlings grown under salt stress. Despite different lettuce varieties exhibiting a distinct response to nanoparticle treatments, results from this study indicate that soluble nanoparticles can significantly improve lettuce seed germination under salinity stress, which provide fundamental evidence on the potential of nanoparticles in agricultural application to improve crop yield and quality under stressful conditions. 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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11 pages, 923 KiB

Open AccessArticle

Genetics of Height and Branching in Faba Bean (Vicia faba)

by Jessa Hughes, Hamid Khazaei and Albert Vandenberg

Agronomy 2020, 10(8), 1191; https://doi.org/10.3390/agronomy10081191 - 13 Aug 2020

Cited by 6 | Viewed by 2890

Abstract

A better understanding of the genetics of plant architecture, including height and branching, could improve faba bean breeding for varieties with better fit into specific cropping systems. This study aimed to determine the inheritance and genetic interactions of the sources of the dwarf [...] Read more.

A better understanding of the genetics of plant architecture, including height and branching, could improve faba bean breeding for varieties with better fit into specific cropping systems. This study aimed to determine the inheritance and genetic interactions of the sources of the dwarf gene (dwf1) and semi-dwarf gene (dwarf1), and to investigate the genetics of branching in the faba bean. We chose inbred lines IG 12658 (dwarf, carrying dwf1) and Rinrei (semi-dwarf, carrying dwarf1) along with Aurora/2 and IG 114476 as sources of non-dwarf faba bean genotypes and crossed them (Aurora/2 × IG 12658, IG 114476 × IG 12658, Rinrei × IG 12658, IG 114476 × Rinrei, and Rinrei × Aurora/2). IG 114476 was also used as a genetic source of a highly branching phenotype and crossed with IG 12658, Rinrei, and Aurora/2 to study the genetics of branching. Parental lines, F₁s, and F₂ populations were evaluated under growth chamber and field conditions in 2018. The segregating F₂ populations were tested for 3:1 single recessive gene inheritance using Chi-square tests. Both dwarfing/semi-dwarfing genes fit 3:1 recessive, and 15:1 for double recessive. Rinrei was not a true dwarf, and the gene creating the dwarf appearance reduced the initial growth rate, but this corrected over time. Multiple F₂ populations were also tested for a 3:1 single dominant gene hypothesis for highly branched phenotypes. These populations showed a bell-shaped phenotypic distribution for branch number, with no discernable classes, and revealed that branching was likely quantitatively controlled. In conclusion, dwarfism and branching in faba bean were controlled qualitatively and quantitatively, respectively. Full article

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

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12 pages, 4801 KiB

Open AccessReview

Revamping of Cotton Breeding Programs for Efficient Use of Genetic Resources under Changing Climate

by Muhammad Salman Mubarik, Chenhui Ma, Sajid Majeed, Xiongming Du and Muhammad Tehseen Azhar

Agronomy 2020, 10(8), 1190; https://doi.org/10.3390/agronomy10081190 - 13 Aug 2020

Cited by 14 | Viewed by 5604

Abstract

Empirical cotton breeding was based upon the concept of selecting single and best high-yielding progeny from the segregating populations to develop a cultivar. It helped in releasing of high yielding varieties with superior fibre quality through conventional breeding. Though the production of cotton [...] Read more.

Empirical cotton breeding was based upon the concept of selecting single and best high-yielding progeny from the segregating populations to develop a cultivar. It helped in releasing of high yielding varieties with superior fibre quality through conventional breeding. Though the production of cotton has been increased manifold in the last decades, but it has also seen enormous ebb and flow of yield uncertainties during the past several years. Therefore, the development of climatic resilient cotton ideotypes through the introduction of wild alleles and using contemporary genetic markers have become inevitable. Emerging genome engineering technologies such as CRISPR/Cas9 system can also potentially exploited to edit the disease susceptible and negative regulators of yield related genes in cotton. In the present review we concentrate on accomplishments and forthcoming of plant breeding and biotechnology to facelift the cotton breeding programs. Full article

(This article belongs to the Special Issue Sustainable Agriculture Based on Crop Ecophysiological Functioning)

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17 pages, 8830 KiB

Open AccessArticle

Genome Wide Identification, Characterization, and Expression Analysis of YABBY-Gene Family in WHEAT (Triticum aestivum L.)

by Zeeshan Ali Buttar, Yuan Yang, Rahat Sharif, Sheng Nan Wu, Yanzhou Xie and Chengshe Wang

Agronomy 2020, 10(8), 1189; https://doi.org/10.3390/agronomy10081189 - 13 Aug 2020

Cited by 16 | Viewed by 3549

Abstract

The small YABBY plant-specific transcription factor has a prominent role in regulating plant growth and developmental activities. However, little information is available about YABBY gene family in Triticum aestivum L. Herein, we identified 21 TaYABBY genes in the Wheat genome database. Then, we [...] Read more.

The small YABBY plant-specific transcription factor has a prominent role in regulating plant growth and developmental activities. However, little information is available about YABBY gene family in Triticum aestivum L. Herein, we identified 21 TaYABBY genes in the Wheat genome database. Then, we performed the conserved motif and domain analysis of TaYABBY proteins. The phylogeny of the TaYABBY was further sub-divided into 6 subfamilies (YABBY1/YABBY3, YABB2, YABBY5, CRC and INO) based on the structural similarities and functional diversities. The GO (Gene ontology) analysis of TaYABBY proteins showed that they are involved in numerous developmental processes and showed response against environmental stresses. The analysis of all identified genes in RNA-seq data showed that they are expressed in different tissues of wheat. Differential expression patterns were observed in not only control samples but also in stressed samples such as biotic stress (i.e., Fusarium graminearum (F.g), septoria tritici (STB), Stripe rust (Sr) and Powdery mildew (Pm), and abiotic stress (i.e., drought, heat, combined drought and heat and phosphorus deficiency), especially at different grain development stages. All identified TaYABBY-genes were localized in the nucleus which implies their participation in the regulatory mechanisms of various biological and cellular processes. In light of the above-mentioned outcomes, it has been deduced that TaYABBY-genes in the wheat genome play an important role in mediating various development, growth, and resistance mechanism, which could provide significant clues for future functional studies. Full article

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19 pages, 2271 KiB

Open AccessArticle

Gains in Genetic Enhancement of Early Maturing Maize Hybrids Developed during Three Breeding Periods under Striga-Infested and Striga-Free Environments

by Baffour Badu-Apraku, Gloria B. Adu, Abdoul-Madjidou Yacoubou, Johnson Toyinbo and Samuel Adewale

Agronomy 2020, 10(8), 1188; https://doi.org/10.3390/agronomy10081188 - 13 Aug 2020

Cited by 8 | Viewed by 2439

Abstract

Striga hermonthica is a major maize production constraint in West and Central Africa (WCA). Fifty-four early maturing maize hybrids of three breeding periods: 2008–2011, 2012–2013, 2014–2015, were evaluated under Striga-infested and non-infested environments in WCA. The study aimed at assessing genetic improvement [...] Read more.

Striga hermonthica is a major maize production constraint in West and Central Africa (WCA). Fifty-four early maturing maize hybrids of three breeding periods: 2008–2011, 2012–2013, 2014–2015, were evaluated under Striga-infested and non-infested environments in WCA. The study aimed at assessing genetic improvement in grain yield of the hybrids, identifying traits associated with yield gain during the breeding periods, and grain yield and stability of the hybrids in Striga infested and non-infested environments. Annual increase in grain yield of 101 kg ha⁻¹ (4.82 %) and 61 kg ha⁻¹ (1.24%) were recorded in Striga-infested and non-infested environments, respectively. The gains in grain yield from period 1 to period 3 under Striga-infested environments were associated with reduced anthesis-silking interval, reduced Striga damage, number of emerged Striga plants, improved ear aspect, and increased ears per plant. Ear aspect, ears per plant, and Striga damage at 8 and 10 weeks after planting (WAP) were significantly correlated with yield in Striga-infested environments, whereas ears per plant and plant and ear aspects had significant correlations with yield in non-infested environments. Hybrids TZdEI 352 × TZEI 355, TZdEI 378 × TZdEI 173, and TZdEI 173 × TZdEI 352 were outstanding in grain yield and stability in Striga-infested environments, whereas TZEI 326 × TZdEI 352, TZEI 495 × ENT 13, and TZdEI 268 × TZdEI 131 were superior in non-stress environments. These hybrids should be further tested extensively and commercialized. Significant genetic gains have been made in breeding for resistance to Striga hermonthica in early maturing maize hybrids. Full article

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Agronomy, Volume 10, Issue 8 (August 2020) – 161 articles

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