Agronomy

18 pages, 7915 KiB

Open AccessArticle

Characterization of SUPPRESSOR OF MAX2 1-LIKE (SMXL) Genes in ‘duli’ (Pyrus betulifolia L.) and Expression Analysis of PbSMXLs in Response to Plant Growth Regulators and Salt Stress

by Shuai Yuan, Weilong Zhang and Yuxing Zhang

Agronomy 2024, 14(12), 2778; https://doi.org/10.3390/agronomy14122778 - 22 Nov 2024

Abstract

SUPPRESSOR OF MAX2 1-LIKE (SMXL) proteins are negative regulators of strigolactone (SL) signal transduction that play an important role in regulating plant branching and responses to abiotic stress. Here, we studied the role of SMXL proteins in pear growth, development, and stress resistance. [...] Read more.

SUPPRESSOR OF MAX2 1-LIKE (SMXL) proteins are negative regulators of strigolactone (SL) signal transduction that play an important role in regulating plant branching and responses to abiotic stress. Here, we studied the role of SMXL proteins in pear growth, development, and stress resistance. A total of 18 SMXL members were characterized in ‘duli’. All SMXL members were localized to chloroplasts. Chromosome mapping analysis showed that the members of this family were unevenly distributed on 14 chromosomes. Gene fragment replication analysis showed that there were no tandem repeat genes in PbSMXLs, and 12 pairs of homologous genes were fragment duplications. There were 30 pairs of homologous genes between ‘duli’ and apples, and 17 between ‘duli’ and Arabidopsis thaliana. Analysis of cis-acting elements showed that there was a large number of photo-effector elements, short-effector elements, hormone-responsive elements, and abiotic stress-responsive elements in the promoter sequences of this family. Analysis of enzyme activity and endogenous SL showed that β-carotenoid isomerase (D27), carotenoid cleavage dioxygenase 7 (CCD7), lateral branch oxidoreductase (LBO) levels, and SL content were higher in ‘duli’ roots and leaves compared in the control under exogenous GA₃ (gibberellin 3), IAA (indole-3-acetic acid), GR24 (synthetic SL analog), and NaCl. Most SMXL genes in ‘duli’ were highly expressed in branches and axillary lobes, but their expression was low in fruits. qRT-PCR analysis revealed that eight PbSMXL genes were responsive to GA₃, PAC (Paclobutrazol), IAA, ABA (abscisic acid), GR24, and Tis108 (SL biosynthesis inhibitor). PbSMXLs responded positively to salt stress. The expression of PbSMXL6 and PbSMXL15 was significantly induced under salt stress. The expression of PbSMXL7, PbSMXL10, and PbSMXL15 was significantly induced by Tis108 treatment. The results of this study enhance our understanding of the role of SMXL genes in the responses to plant growth regulators and salt stress. Our findings will also aid future studies of the functions of SMXL genes in ‘duli’. Full article

(This article belongs to the Section Plant-Crop Biology and Biochemistry)

15 pages, 1739 KiB

Open AccessArticle

Analysis of the Impact of Digital Inclusive Finance on the Development of Green Agriculture

by Zhuoya Ma, Zhentao Liu, Pan Zhang, Xue Wei and Wenhui Chen

Agronomy 2024, 14(12), 2777; https://doi.org/10.3390/agronomy14122777 - 22 Nov 2024

Abstract

Agricultural green development plays a crucial role in addressing the conflict between agricultural production and ecological environmental protection. This study aims to analyze the impact and mechanisms through which digital inclusive finance influences agricultural green development, providing empirical evidence to support the role [...] Read more.

Agricultural green development plays a crucial role in addressing the conflict between agricultural production and ecological environmental protection. This study aims to analyze the impact and mechanisms through which digital inclusive finance influences agricultural green development, providing empirical evidence to support the role of digital inclusive finance in promoting sustainable agricultural practices. Using panel data from 30 provinces (cities and districts) in China spanning from 2011 to 2020, this study measures regional agricultural green development levels using the entropy power method. By clarifying the theoretical mechanisms behind the relationship between digital inclusive finance and agricultural green development, this research employs panel fixed effects, mediation effects, and threshold regression models to empirically examine the impact of digital inclusive finance, specifically its coverage breadth, usage depth, and digitization level, on agricultural green development. Furthermore, this study explores the threshold effects of digital inclusive finance on agricultural green development. The findings from this study indicate that digital inclusive finance significantly contributes to agricultural green development, with a double-threshold effect observed as follows: when digital inclusive finance surpasses critical thresholds, its impact on agricultural green development intensifies. This result remains robust after conducting a series of endogeneity and robustness tests. The mechanism analysis reveals that digital inclusive finance drives agricultural green development by fostering technological innovation and increasing farmers’ income. Heterogeneity analysis further demonstrates that digital inclusive finance has a substantial impact on agricultural green development in eastern China compared to the central and western regions. Consequently, this study suggests that digital inclusive financial services should be further expanded and deepened to foster the integration of financial services with agriculture, creating a sustainable development model that promotes shared prosperity and effectively supports the green development of agriculture. Full article

(This article belongs to the Section Farming Sustainability)

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11 pages, 2585 KiB

Open AccessArticle

Production of Bacillus thuringiensis in “On Farm” Biofactories Is So Efficient Like a Commercial Product to Control Spodoptera frugiperda (Lepidoptera: Noctuidae)

by Ítalo Alves Freire, Izabela Nunes do Nascimento, Gabriela Teodoro Rocha, Pedro de Luca Buffon dos Santos, Breno Béda dos Reis Cunha, Antônia Débora Camila de Lima Ferreira, Flávia Melo Moreira, Marcelo Tavares de Castro and Rose Gomes Monnerat

Agronomy 2024, 14(12), 2776; https://doi.org/10.3390/agronomy14122776 - 22 Nov 2024

Abstract

The biological control of pests and diseases in Brazilian crops has increased substantially, and the large-scale multiplication of microorganisms, a practice known as “On Farm”, is now being used by farmers. In this study, we aimed to produce and evaluate the quality of [...] Read more.

The biological control of pests and diseases in Brazilian crops has increased substantially, and the large-scale multiplication of microorganisms, a practice known as “On Farm”, is now being used by farmers. In this study, we aimed to produce and evaluate the quality of Bacillus thuringiensis var. kurstaki strain HD-1 in “On Farm” biofactories under three aeration rates (0.2, 0.5 and 0.8 air volume/volume of medium/min) (vvm), with regard to the production of endospores and crystals, contaminants, and to calculate the lethal concentration 50 (LC₅₀) against Spodoptera frugiperda larvae. After 48 h, the number of viable spores differed significantly between 0.2 (5.75 × 10⁷), 0.5 (1.33 × 10⁸) and 0.8 (5.40 × 10⁸) vvm. The culture media did not show enough selectivity. A significant difference was observed for the LC₅₀ calculated for 0.2 vvm (7.06 × 10⁴), 0.5 vvm (2.07 × 10⁴), 0.8 vvm (4.40 × 10³), and the commercial product (3.79 × 10³). The results of this study showed that the aeration rate affects the multiplication efficiency of B. thuringiensis in biofactories. In addition, post-process quality control analyses found no pathogenic contamination, reinforcing the safety and viability of the production process. The 0.8 vvm rate resulted in the greater production of spores and crystals, and statistically similar results to the commercial product for the control of S. frugiperda. Full article

(This article belongs to the Special Issue Biological Pest Control in Agroecosystems)

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16 pages, 3089 KiB

Open AccessArticle

The Path Towards Novel Varieties: Investigating Phenotypic-Genetic Diversity in New Promising Egyptian Rice Lines

by Waleed A. Almasoud, Mahmoud Abdel-Sattar, Saber Sedeek, Amgad A. Elgammaal, Nouran El-Refaee, Ibrahem A. Ramadan, Dina Abdulmajid and Hail Z. Rihan

Agronomy 2024, 14(12), 2775; https://doi.org/10.3390/agronomy14122775 - 22 Nov 2024

Abstract

Rice (Oryza sativa L.) has an impressive range of phenotypic and genetic diversity, making it an important crop for global food security. Since rice phenotypic and genetic diversity are essential for enhancing the sustainability of rice production, an understanding of these variations [...] Read more.

Rice (Oryza sativa L.) has an impressive range of phenotypic and genetic diversity, making it an important crop for global food security. Since rice phenotypic and genetic diversity are essential for enhancing the sustainability of rice production, an understanding of these variations is crucial for breeding efforts. Numerous factors, such as plant height, panicle number, grain properties, etc., exhibit phenotypic diversity in rice. Moreover, genetic diversity is essential for breeding and enhancing rice in multiple manners. This research investigates the phenotypic diversity of thirteen promising lines relative to their parents. Since the genetic effect reflects the plant’s phenotype, forty SSR markers were used to investigate the genotypic diversity. Generally, six promising genotypes produced much better grain yields than their parents. Across two years, the number of filled grains panicle⁻¹ and the number of unfilled grains panicle⁻¹ had the highest phenotypic and genotypic coefficients of variability percentage. The challenges towards novel variety with distinct characteristics were met in several promising lines under examination, which showed a significant and positive association between the grain yield and the number of panicles per plant, the number of filled grains per panicle, and the 1000-grain weight. Furthermore, five SSR markers were discovered to be polymorphic during the genetic diversity investigation, and the genotypes were classified into five clusters based on SSR marker data. The findings, together with further details, can be used to release novel and unique varieties. Full article

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

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25 pages, 7079 KiB

Open AccessArticle

Research Progress on Land Use and Analysis of Green Transformation in China Since the New Century

by Wei He, Jianzhou Gong and Xiaobin Zeng

Agronomy 2024, 14(12), 2774; https://doi.org/10.3390/agronomy14122774 - 22 Nov 2024

Abstract

The optimization of land use structure is a key measure to promote the allocation of land resources, ensure sustainable land development, and address the human-land conflict. Since the 21st century, land use in China has exhibited spatiotemporal dynamic development characteristics in response to [...] Read more.

The optimization of land use structure is a key measure to promote the allocation of land resources, ensure sustainable land development, and address the human-land conflict. Since the 21st century, land use in China has exhibited spatiotemporal dynamic development characteristics in response to socio-economic growth and changes in regional geographical conditions. The academic community, both domestically and internationally, has enriched and refined the research system on China’s land use, driven by the need to optimize its land use structure. This study systematically reviews relevant land use research literature from 2000 to 2024, utilizing bibliometric analysis and visual mapping to conduct phased evaluations and an overall review. The existing LUCC research framework in China is extensive, with a strong focus on land use issues in the context of rapid development. Building on this review and incorporating practical needs, theoretical innovation, interdisciplinary integration, and expansion across multiple fields, we aim to propose a framework for future land resource research. This framework includes: (i) Establishing a Multi-functional Land Use System: This approach promotes the coordinated development of ecological and social benefits of land use. (ii) Enhancing Effective Assessment and Management of Ecological Risks: Such efforts contribute to optimizing spatial planning and ensuring land security. (iii) Addressing Low Land Use Efficiency: Focusing on this issue will enable more precise management aligned with regional characteristics. (iv) Exploring the Application of Multi-disciplinary and Cross-field Technologies in Land Use Efficiency Assessment: This integration will advance spatial planning research. (v) Expanding Research on Multi-functional Land Use and Multi-element Integration: This direction fosters coordination across various planning frameworks, promoting synergies in land use research. Full article

(This article belongs to the Special Issue Land Degradation and Management Strategies: Contributing to Sustainable Agriculture)

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13 pages, 2898 KiB

Open AccessArticle

Development and Trait-Based Molecular Characterization of Thermosensitive Genic Male-Sterile Rice (Oryza sativa L.) Lines at Texas A&M AgriLife Research

by Darlene L. Sanchez, Stanley Omar PB. Samonte, Kimberly S. Ponce, Zongbu Yan and Lloyd T. Wilson

Agronomy 2024, 14(12), 2773; https://doi.org/10.3390/agronomy14122773 - 22 Nov 2024

Abstract

This study aimed to develop and genetically characterize thermosensitive genic male-sterility (TGMS) lines for use in hybrid rice (Oryza sativa L.) breeding. Male-sterile F₂ to F₄ generation lines were screened during the high-temperature summer season, and ratoon crops of selected [...] Read more.

This study aimed to develop and genetically characterize thermosensitive genic male-sterility (TGMS) lines for use in hybrid rice (Oryza sativa L.) breeding. Male-sterile F₂ to F₄ generation lines were screened during the high-temperature summer season, and ratoon crops of selected male-sterile rows were harvested for pure seed. Sixty-six F₅ TGMS lines were genotyped using DNA markers controlling 16 traits from the LSU80 QA/QC Rice PlexSeq SNP Panel. Ten TGMS lines with desirable traits that included semidwarf, glabrous, non-aromatic, long-grain, narrow brown leaf spot resistance, and blast resistance genes were selected for further genotypic characterization using markers for low chalkiness (chalk5), wide compatibility (S5-n), cold tolerance (qSCT-11 and qCST-12), and anaerobic germination (AG1 and AG2). TGMS lines TIL21051S and TIL21052S possess favorable alleles for each of the genes evaluated in this study and are desirable parents for two-line hybrid breeding in the southeast United States. TIL21044S, TIL21095S, TIL21060S, and TIL21066S each contain three blast resistance genes and have potential as parental lines. TIL21014S-2, TIL21015S, and TIL21016S-1 include the fgr allele for aroma and can also be used as parental lines for aromatic two-line hybrids. Full article

(This article belongs to the Special Issue Marker Assisted Selection and Molecular Breeding in Major Crops)

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14 pages, 7595 KiB

Open AccessArticle

Environmental Constraints Mitigation Directly Drove the Diversifications of Fungal Community and Functional Profile in Amended Coastal Salt-Affected Soils

by Yunlong Li, Weifeng Chen, Yiwei Xu, Jie Yu, Wengang Zuo, Yuhua Shan and Yanchao Bai

Agronomy 2024, 14(12), 2772; https://doi.org/10.3390/agronomy14122772 - 22 Nov 2024

Abstract

Although organic amendment has been widely demonstrated to be capable of reassembling soil microbiomes in coastal salt-affected soils, quantitative characterization in respect to how abiotic and biotic components drive the diversifications of soil microbial community and function remains rudimentary. We investigated the effects [...] Read more.

Although organic amendment has been widely demonstrated to be capable of reassembling soil microbiomes in coastal salt-affected soils, quantitative characterization in respect to how abiotic and biotic components drive the diversifications of soil microbial community and function remains rudimentary. We investigated the effects of types and application rates of different exogenous organic ameliorants (sewage sludge, S; vermicompost, V) on the physicochemical properties, fungal community diversity, and fungal functional traits in coastal salt-affected soils. Results revealed that both S and V amendments exhibited significantly positive impacts on the alleviation of environmental constraints and the reassembly of fungal community and functional profile. Of note, efficacy of the two exogenous organic ameliorants was significantly influenced by the types of carbon sources utilized and the rates at which they are applied. More pronounced variations in soil physicochemical and microbiological properties were observed in soils amended by S and V at the application rate of 200 t ha⁻¹. Both S and V treatments positively boosted soil fungal community diversification with higher compositional diversities found in the majority of amended soils when compared to unamended soils. In addition, S and V applications favored the flourishment of functions linked to saprotrophic strategy with soil saprotrophs and wood saprotrophs predominating the functional profiles in soils amended by S and V, respectively. Results obtained from redundancy analysis and structural equation modeling revealed that pH, salinity, and SOC were the principle edaphic factors that significantly and directly affected the reassembly of fungal community. In addition, fluctuations in the prevalence of specific fungal genera, including Stachybotrys, Trichoderma, Mortierella, and Acremonium, emerged as a decisive biotic factor influencing diversifications of fungal communities and functional profiles. Taken together, this study not only highlighted the efficacy of S and V application on environmental constraints alleviation in coastal mudflats, but also qualitatively identified and quantitatively illustrated potential pathways and effectiveness of edaphic and biotic components driving the diversification of soil fungal microbiomes and functional profiles. These findings would enhance our understanding in respect to the microbial-mediated amelioration process of salt-affected soils within coastal mudflat ecosystem. Full article

(This article belongs to the Special Issue Innovations and Obstacles: Microbial Communities in the Journey of Soil Remediation)

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19 pages, 5368 KiB

Open AccessArticle

Cladophialophora guangxiense sp. nov., a New Species of Dark Septate Endophyte, Mitigates Tomato Bacterial Wilt and Growth Promotion Activities

by Xihong Wei, Yanyan Long, Yanlu Chen, Stanley Nyenje Mataka, Xue Jiang, Yi Zhou, Zhengxiang Sun and Ling Xie

Agronomy 2024, 14(12), 2771; https://doi.org/10.3390/agronomy14122771 - 22 Nov 2024

Abstract

Bacterial wilt of tomatoes, caused by Ralstonia solanacearum, is a significant soilborne disease that often causes significant reductions in the yield of tomatoes. Dark septate endophytic fungi (DSE) represent potential biocontrol agents against plant pathogens that can also enhance plant growth. To collect [...] Read more.

Bacterial wilt of tomatoes, caused by Ralstonia solanacearum, is a significant soilborne disease that often causes significant reductions in the yield of tomatoes. Dark septate endophytic fungi (DSE) represent potential biocontrol agents against plant pathogens that can also enhance plant growth. To collect DSE fungi with potential for biocontrol, the fungus Cladophialophora guangxiense HX2 was isolated from the rhizosphere soil of sugarcane in Hengzhou Guangxi Province, China, and a novel species of Cladophialophora was identified based on morphological properties and DNA sequence analysis. C. guangxiense HX2 demonstrated a controlling effect of 76.7% on tomato bacterial wilt and promoted a 0.5-fold increase in tomato seedling height. It colonized tomato seedling roots, enhancing the activity of antioxidant and defensive enzyme systems. Transcriptomic and qPCR approaches were used to study the induction response of the strain HX2 infection by comparing the gene expression profiles. Gene ontology (GO) and Kyoto Encyclopedia of Gene and Genome (KEGG) pathway enrichment revealed that tomatoes can produce salicylic acid metabolism, ethylene-activated signaling, photosynthesis, and phenylpropanoid biosynthesis to the strain HX2 infection. The expression of IAA4 (3.5-fold change), ERF1 (3.5-fold change), and Hqt (1.5-fold change) was substantially enhanced and Hsc 70 (0.5-fold change) was significantly reduced in the treatment group. This study provides a theoretical foundation for further investigation into the potential of C. guangxiense HX2 as a biological agent for the prevention and control of tomato bacterial wilt. Full article

(This article belongs to the Special Issue Advanced Research on Diagnosis and Biological Control of Crop Diseases)

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29 pages, 24931 KiB

Open AccessArticle

An Efficient Computer Vision-Based Dual-Face Target Precision Variable Spraying Robotic System for Foliar Fertilisers

by Chengtian Zhu, Shuaihua Hao, Cailing Liu, Yuewei Wang, Xuan Jia, Jitong Xu, Songbao Guo, Juxin Huo and Weiming Wang

Agronomy 2024, 14(12), 2770; https://doi.org/10.3390/agronomy14122770 - 22 Nov 2024

Abstract

The application of foliar fertiliser can rapidly replenish the essential nutrients required by crops. In order to enhance the precision of foliar fertiliser spraying, fertiliser utilisation, and leaf absorption efficiency, this study proposes the implementation of an efficient foliar fertiliser dual-face target precision [...] Read more.

The application of foliar fertiliser can rapidly replenish the essential nutrients required by crops. In order to enhance the precision of foliar fertiliser spraying, fertiliser utilisation, and leaf absorption efficiency, this study proposes the implementation of an efficient foliar fertiliser dual-face target precision variable spraying robot system based on computer vision. In this study, we propose the SN-YOLOX Nano-ECA as a real-time classification model for potted plants. The model has parameters and FLOPs of only 0.48 M and 0.16 G, respectively. Following deployment, the classification precision and recall reached 97.86% and 98.52%, respectively, with an FPS of 37.6. A dual-face target precision variable spraying method of foliar fertiliser based on the determination of leaf area and plant height information of potted plants was proposed. A robot platform for the application of foliar fertilisers was developed, and a positioning and navigation system based on the RSSI principle was constructed. The results of the foliar fertiliser spraying experiments demonstrate that the precision of the extracted leaf area and height information is above 97% and 96%, respectively. The navigation system demonstrated distance and angle errors of only 5.598 cm and 0.2245°. The mean discrepancy between the actual and set spraying volumes was 0.46 mL. This robotic system is capable of precise spraying of foliar fertiliser, which provides a new idea and reference for the development of efficient and precise variable spraying technology for foliar fertiliser. Full article

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

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17 pages, 3068 KiB

Open AccessArticle

Effect of Digitaria eriantha Endophytic Bacteria on Maize Growth in a Hydroponic System

by Johny J. Mendonça, Michelle J. G. Alves, Gisely M. Vitalino, Maria C. S. Barreto, Eric X. Carvalho, José P. Oliveira, Maria L. R. B. Silva, Felipe J. C. Fracetto, Giselle G. M. Fracetto and Mario A Lira Junior

Agronomy 2024, 14(12), 2769; https://doi.org/10.3390/agronomy14122769 - 22 Nov 2024

Abstract

Brazil is one of the largest grain producers worldwide, with yields heavily dependent on ecologically and financially expensive inputs. One possible approach to reduce these inputs is inoculation with plant-growth-promoting bacteria, whose large-scale use depends on a continual search for new genotypes for [...] Read more.

Brazil is one of the largest grain producers worldwide, with yields heavily dependent on ecologically and financially expensive inputs. One possible approach to reduce these inputs is inoculation with plant-growth-promoting bacteria, whose large-scale use depends on a continual search for new genotypes for inoculant production. Several bacteria with potential for this have been isolated from plants that are more adapted to stressful environments. Thus, we aimed to evaluate the potential of pangolão grass (Digitaria eriantha cv. Suvernola) endophytic bacteria both in vitro and on maize growth. To this end, endophytic bacteria were isolated from pangolão grass of a tropical semiarid climate and a random subset of 80 strains was evaluated for biological nitrogen fixation, HCN, IAA and siderophore production and calcium phosphate solubilization, and later for maize growth promotion. All strains were positive for at least one of these in vitro growth promotion mechanisms and some strains increased maize plant height and root length, including some with better results than plants receiving commercial inoculants, confirming the potential of endophytic bacteria from stress-adapted plants. In vitro results had poor correlation with plant growth promotion, which indicates that the common practice of using these laboratory techniques as a pre-selection tool before a subset of strains is evaluated for plant growth promotion might result in the rejection of potentially interesting strains. Full article

(This article belongs to the Special Issue Innovative Research on Soil Microbial Ecosystem and Its Interaction with Crop Plants)

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19 pages, 5017 KiB

Open AccessArticle

Genomic Selection in Alfalfa Across Multiple Ploidy Levels: A Comparative Study Using Machine Learning and Bayesian Methods

by Xiaoyue Zhu, Ruixin Zhang, Tianxiang Zhang, Changhong Guo and Yongjun Shu

Agronomy 2024, 14(12), 2768; https://doi.org/10.3390/agronomy14122768 - 21 Nov 2024

Abstract

Agronomic traits and quality traits of alfalfa are of great importance to the feed industry. Genomic selection (GS) based on genotyping-by-sequencing (GBS) data, if it achieves moderate to high accuracy, has the potential to significantly shorten breeding cycles for complex traits and accelerate [...] Read more.

Agronomic traits and quality traits of alfalfa are of great importance to the feed industry. Genomic selection (GS) based on genotyping-by-sequencing (GBS) data, if it achieves moderate to high accuracy, has the potential to significantly shorten breeding cycles for complex traits and accelerate genetic progress. This study aims to investigate the effect of different reference genomes on the prediction accuracy of genomic selection. A total of 11 Bayesian and machine learning models and nine different reference genomes were used to conduct genomic selection on five traits in 385 alfalfa accessions. The accuracy of GS was evaluated using five-fold cross-validation, based on the correlation between genomic estimated breeding values (GEBVs) and estimated breeding values (EBVs). For the five traits, it was found that traits with high heritability exhibited significantly higher prediction accuracy. The prediction accuracy fluctuated minimally across different reference genomes, with the diploid genome showing relatively higher accuracy. For two high-heritability traits, fall dormancy and plant height, predictions were made after SNP density reduction, and it was observed that density had little effect on prediction accuracy. However, for the fall dormancy trait in the diploid genome, more than half of the models showed regular fluctuations, with prediction accuracy increasing as SNP density increased. In conclusion, this study provides a theoretical basis for precision breeding of alfalfa and other polyploid crops by combining different reference genomes and models, and offers important guidance for optimizing future genomic selection strategies. Full article

(This article belongs to the Special Issue Innovations in Assessing G×E×M Interactions: Advancing Agronomy and Modeling Strategies for Sustainable Crop Production)

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18 pages, 3634 KiB

Open AccessArticle

Insights into the Driving Factors of Methane Emission from Double-Season Rice Field Under Different Fertilization Practices in South China

by Jin Zheng, Yusheng Lu, Peizhi Xu, Kaizhi Xie, Changmin Zhou, Yaying Li, Haoyang Geng, Qianyuan Wang and Wenjie Gu

Agronomy 2024, 14(12), 2767; https://doi.org/10.3390/agronomy14122767 - 21 Nov 2024

Abstract

Paddy fields are the main agricultural source of greenhouse gas methane (CH₄) emissions. To enhance rice yield, various fertilization practices have been employed in rice paddies. However, the key microbial and abiotic factors driving CH₄ emissions under different fertilization practices [...] Read more.

Paddy fields are the main agricultural source of greenhouse gas methane (CH₄) emissions. To enhance rice yield, various fertilization practices have been employed in rice paddies. However, the key microbial and abiotic factors driving CH₄ emissions under different fertilization practices in paddy fields remain largely uncharted. This study conducted field experiments in a traditional double-cropping rice area in South China, utilizing five different fertilization practices to investigate the key factors influencing CH₄ emissions. High-throughput sequencing and PICRUSt2 functional prediction were employed to investigate the contributions of soil physicochemical properties, CH₄-metabolizing microorganisms (methanogens and methanotrophs), and key genes (mcrA and pmoA) on CH₄ emissions. The results showed that CH₄ emission fluxes exhibited seasonal variations, with consistent patterns of change observed across all treatments for both early- and late-season rice. Compared to the no-fertilization (NF) treatment, cumulative CH₄ emissions were lower in early-season rice with green manure (GM) and straw returning (SR) treatments, as well as in late-season rice with GM treatment, while rice yields were maintained at higher levels. High-throughput sequencing analysis revealed that potential methanogens were primarily distributed among four orders: Methanobacteriales, Methanocellales, Methanomicrobiales, and Methanosarcinales. Furthermore, there was a significant positive correlation between the relative abundance of the CH₄-related key gene mcrA and these microorganisms. Functional analysis indicated that these potential methanogens primarily produce methane through the acetoclastic and hydrogenotrophic pathways. Aerobic CH₄-oxidizing bacteria, predominantly from the genus Methylocystis, were detected in all the treatments, while the CH₄ anaerobic-oxidizing archaea ANME-1b was only detected in chemical fertilization (CF) and cow manure (CM) treatments. Our random forest analysis revealed that the relative abundance of two methanogens (Methanocellales and Methanosarcinales) and two environmental factors (pH and DOC) had significant impacts on the cumulative CH₄ emissions. The variance decomposition analysis highlighted the CH₄-metabolizing microorganisms explained 50% of the variance in the cumulative CH₄ emissions, suggesting that they are the key microbial factors driving CH₄ emissions. These findings provide guidance for the development of rational measures to reduce CH₄ emissions in paddy fields. Full article

(This article belongs to the Special Issue Metagenomic Analysis for Unveiling Agricultural Microbiome—2nd Edition)

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17 pages, 1064 KiB

Open AccessArticle

Effective Control of Neofusicoccum parvum in Grapevines: Combining Trichoderma spp. with Chemical Fungicides

by Aranzazu Gomez-Garay, Sergio Astudillo Calderón, Mª Luisa Tello Mariscal and Beatriz Pintos López

Agronomy 2024, 14(12), 2766; https://doi.org/10.3390/agronomy14122766 - 21 Nov 2024

Abstract

Vitis vinifera is highly susceptible to grapevine trunk diseases, with Neofusicoccum parvum recognized as a highly destructive pathogen. This study investigates the biocontrol potential of five Trichoderma species (T. harzianum, T. viride, T. asperellum, and T. virens) against [...] Read more.

Vitis vinifera is highly susceptible to grapevine trunk diseases, with Neofusicoccum parvum recognized as a highly destructive pathogen. This study investigates the biocontrol potential of five Trichoderma species (T. harzianum, T. viride, T. asperellum, and T. virens) against N. parvum, evaluating multiple biocontrol mechanisms (mycoparasitism, competition for nutrients, production of volatile organic compounds (VOCs), and antibiosis) as well as their compatibility with the fungicides copper oxychloride and sulfur. Results demonstrated that (1) Trichoderma harzianum effectively suppressed N. parvum through VOC production, mycoparasitism, and nutrient competition, significantly reducing pathogen growth in planta while showing compatibility with both fungicides, highlighting its suitability for integrated disease management; (2) Trichoderma viride showed high inhibition of N. parvum in vitro, but its phytotoxicity in planta limits its field application. These findings support T. harzianum as a promising agent within integrated disease management strategies, offering a sustainable alternative to reduce chemical fungicide reliance in controlling grapevine trunk pathogens. Full article

(This article belongs to the Special Issue Agrochemistry and Application of Natural Products to Agricultural Research)

15 pages, 1465 KiB

Open AccessArticle

Validation of KASP Markers Associated with Hydrogen Cyanide in Fresh Cassava Roots in Uganda Cassava Germplasm

by Michael Kanaabi, Settumba B. Mukasa, Ephraim Nuwamanya, Paula Iragaba, Julius Karubanga Baguma, Ann Ritah Nanyonjo, Henry Wagaba, Nicholas Muhumuza, Fatumah Babirye Namakula, Enoch Wembabazi, Alfred Ozimati, Ismail Siraj Kayondo, Williams Esuma and Robert S. Kawuki

Agronomy 2024, 14(12), 2765; https://doi.org/10.3390/agronomy14122765 - 21 Nov 2024

Abstract

Low hydrogen cyanide (HCN) concentration is a high-priority trait for cassava varieties targeting their fresh and dry product profiles. To be acceptable, varieties bred and developed for these market segments must meet international safety standards for maximum acceptable residual levels of cyanide in [...] Read more.

Low hydrogen cyanide (HCN) concentration is a high-priority trait for cassava varieties targeting their fresh and dry product profiles. To be acceptable, varieties bred and developed for these market segments must meet international safety standards for maximum acceptable residual levels of cyanide in cassava food and food products. The discovery of molecular markers that co-segregate with low HCN has not yet resulted in widespread usage in marker-assisted selection (MAS) in breeding programs. To deploy these HCN markers in regular MAS, assessing their reliability in various genetic backgrounds is crucial. The aim of this study was to assess the predictive accuracy of trait specific markers for HCN. The study used six HCN kompetitive allele-specific polymerase chain reaction (KASP) markers that had previously been developed in a Brazilian population and verified in segregating West African cassava populations. For most markers used in the study, the average call rate was more than 91.7%. Three markers—snpME00404, snpME00405 and snpME00406—showed a significant co-segregation of genotypes with the HCN phenotype. On average, genotypes that carried at least one copy of the favourable allele had lower HCN scores. The proportion of phenotypic variance accounted for by the three most important markers was 14% (snpME00406), 17% (snpME00405) and 27% (snpME00404). The validation of identified HCN SNP-markers marks a significant step in their deployment to support selection and advancement decisions in cassava breeding programs. Full article

(This article belongs to the Special Issue Genetics and Breeding of Field Crops in the 21st Century)

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16 pages, 1136 KiB

Open AccessArticle

Grapefruit Extracts and Black Chokeberry Juice as Potential Antioxidant and Antifungal Agents for Carrot Seed Treatment

by Magdalena Jarosz, Hanna Dorna, Dorota Szopińska, Włodzimierz Krzesiński and Artur Szwengiel

Agronomy 2024, 14(12), 2764; https://doi.org/10.3390/agronomy14122764 - 21 Nov 2024

Abstract

Grapefruit extracts and black chokeberry juice have antioxidant and antimicrobial properties. The aim of the experiment was to evaluate the effect of grapefruit-based preparations, Biosept Active and Citrogrep, and black chokeberry juice on the germination, vigor, and health of carrot seeds. The seeds [...] Read more.

Grapefruit extracts and black chokeberry juice have antioxidant and antimicrobial properties. The aim of the experiment was to evaluate the effect of grapefruit-based preparations, Biosept Active and Citrogrep, and black chokeberry juice on the germination, vigor, and health of carrot seeds. The seeds of two cultivars were soaked for 30 min in 0.25% grapefruit-based preparations and in 5 and 25% chokeberry juice. Standard ISTA methods were used to evaluate seed germination and health. The chemical composition of the applied preparations and juice was analyzed with ultra-high-performance liquid chromatography electrospray ionization mass spectrometry. The grapefruit-based preparations differed significantly in their chemical composition, qualitatively and quantitatively, but in both of them, flavanones and flavones prevailed. Biosept Active improved seed germination especially in the cultivar, which was characterized by a lower initial seed quality. The significant positive correlations between germination at the first and final counts, as well as the contents of flavanones and flavones, were identified in this cultivar. Moreover, the negative correlations between the percentages of diseased seedlings, dead seeds, the percentages of seed infested with Cladosporium spp., Epicoccum nigrum, Melanospora simplex, and Ulocladium spp., and the investigated compounds were found. Chokeberry juice, at the higher concentration, showed some antioxidant activity; however, it frequently stimulated the growth of the fungi. Full article

(This article belongs to the Special Issue Natural Products in Crop Diseases Control)

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12 pages, 2077 KiB

Open AccessArticle

The Impact of Humic Acid Fertilizers on Crop Yield and Nitrogen Use Efficiency: A Meta-Analysis

by Yunqi Ma, Xiaoyu Cheng and Yuyang Zhang

Agronomy 2024, 14(12), 2763; https://doi.org/10.3390/agronomy14122763 - 21 Nov 2024

Abstract

Humic acid, as a novel organic fertilizer, has the potential to improve soil fertility and the agronomic performance of crops. However, the efficacy of humic acid varied in previous studies and the mechanisms by which climatic conditions, soil properties, and fertilization regimes regulate [...] Read more.

Humic acid, as a novel organic fertilizer, has the potential to improve soil fertility and the agronomic performance of crops. However, the efficacy of humic acid varied in previous studies and the mechanisms by which climatic conditions, soil properties, and fertilization regimes regulate it remain unclear. To test this, a comprehensive meta-analysis was conducted to evaluate the effects of humic acid across various environmental and agricultural conditions. The results showed that the humic acid amendment significantly increased the crop yield by 12%, nitrogen use efficiency by 27%, and nitrogen uptake by 17%, on average. Optimal effects were observed in regions with an annual precipitation > 300 mm and mean annual temperatures > 10 °C, and in soils with a moderate pH (6 < pH ≤ 8) or low total nitrogen. Its efficacy was attenuated in alkaline soils and high total nitrogen (≤1.5 g kg⁻¹) or low soil organic carbon (<10 g kg⁻¹) conditions. Cash crops and upland cereals showed a superior response compared to paddy rice, with optimal nitrogen application rates of 100–200 kg ha⁻¹. This study quantifies humic acid’s positive impacts on crop productivity and nitrogen utilization across various conditions, providing empirical evidence for optimizing its application in sustainable agricultural systems, potentially reducing excessive fertilizer use and its associated environmental pollution. Full article

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

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21 pages, 534 KiB

Open AccessArticle

Fostering Sustainable Potato Production: A Collaborative European Approach

by Alicia Morugán-Coronado, María Dolores Gómez-López, Laura Meno, David Fernández-Calviño, Hilde Wustenberghs, Stefan Schrader, David-Alexander Bind, Anne Põder, Merrit Shanskiy, Eija Pouta, Annika Tienhaara and Javier Calatrava

Agronomy 2024, 14(12), 2762; https://doi.org/10.3390/agronomy14122762 - 21 Nov 2024

Abstract

Potato production faces increasingly severe agronomic problems, including intensive production and pedoclimatic changes. Increasing pest/disease incidence is contributing to inadequate application of pesticides and external fertilizers. This study aims to identify critical agri-environmental challenges currently faced by potato growers in Europe, assessing the [...] Read more.

Potato production faces increasingly severe agronomic problems, including intensive production and pedoclimatic changes. Increasing pest/disease incidence is contributing to inadequate application of pesticides and external fertilizers. This study aims to identify critical agri-environmental challenges currently faced by potato growers in Europe, assessing the needs and priorities of end-users to determine the feasibility of integrating more sustainable farming practices into potato cultivation. Additionally, we identified sustainable strategies to reduce reliance on external inputs. A total of 203 potato stakeholders from six European pedoclimatic areas completed a survey in 2020 to identify agronomic and environmental problems, priorities for action, and best-suited sustainable farming practices. Statistical and multicriteria decision analysis was then performed. Subsequently, focus group meetings with stakeholders were organized to present and discuss results and validate and complement them. Stakeholders perceived that more sustainable potato production involved reducing tillage intensity, using organic nutrient sources, increasing soil organic matter and, especially, diversifying crop rotations. Barriers to adopting new sustainable practices included farmers’ lack of knowledge regarding novel farming practices and the need for expert technical advice. Some practices are complex, but also economic impediments. Therefore, thorough research, clear demonstrations, and tailored advice are crucial to farmers to lead agriculture toward profitable, sustainable systems. Full article

(This article belongs to the Section Farming Sustainability)

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13 pages, 3863 KiB

Open AccessArticle

Effects of Potassium Fertilizer on Sugarcane Yields and Plant and Soil Potassium Levels in Louisiana

by Richard M. Johnson, Katie A. Richard and Quentin D. Read

Agronomy 2024, 14(12), 2761; https://doi.org/10.3390/agronomy14122761 - 21 Nov 2024

Abstract

The influence of potassium fertilizer on sugarcane (interspecific hybrids of Saccharum Spp.) yields and leaf and soil potassium levels was evaluated at six locations in Louisiana. The objective of this study was to determine if the sugarcane yields in Louisiana could be improved [...] Read more.

The influence of potassium fertilizer on sugarcane (interspecific hybrids of Saccharum Spp.) yields and leaf and soil potassium levels was evaluated at six locations in Louisiana. The objective of this study was to determine if the sugarcane yields in Louisiana could be improved with potassium application. Different rates of potassium fertilizer (0–179 kg K₂O ha⁻¹) were applied to plant cane and ratoon sugarcane fields in Louisiana. Soil samples and sugarcane leaf samples were also collected from all experiments. Yield data were collected by harvesting plots with a single row, chopper harvester and a field transport wagon equipped with electronic load sensors. At all locations and soil types, potassium fertilizer did not increase cane or sugar yields. Soil properties data showed that significant increases in soil potassium levels did not occur until the second ratoon crop, where soil potassium increased by 30% for the high rate. Increases in plant potassium were also not observed until the second ratoon crop, where plant potassium increased by 10.5% for the high rate. The potential cause of the observed lack of response may be explained by interference from calcium and magnesium, combined with fixation by smectite and vermiculite clay minerals. Our soil and plant uptake data would suggest that repeated K applications at recommended rates, which currently vary from 90 to 157 kg ha⁻¹, may be required to achieve the potential benefits of K fertilizer in Louisiana sugarcane soils. However, this must be verified by additional on-farm trials. Full article

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

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20 pages, 9880 KiB

Open AccessArticle

Estimating Rice Leaf Nitrogen Content and Field Distribution Using Machine Learning with Diverse Hyperspectral Features

by Ting Tian, Jianliang Wang, Yueyue Tao, Fangfang Ji, Qiquan He, Chengming Sun and Qing Zhang

Agronomy 2024, 14(12), 2760; https://doi.org/10.3390/agronomy14122760 - 21 Nov 2024

Abstract

Leaf nitrogen content (LNC) is a vital agronomic parameter in rice, commonly used to evaluate photosynthetic capacity and diagnose crop nutrient levels. Nitrogen deficiency can significantly reduce yield, underscoring the importance of accurate LNC estimation for practical applications. This study utilizes hyperspectral UAV [...] Read more.

Leaf nitrogen content (LNC) is a vital agronomic parameter in rice, commonly used to evaluate photosynthetic capacity and diagnose crop nutrient levels. Nitrogen deficiency can significantly reduce yield, underscoring the importance of accurate LNC estimation for practical applications. This study utilizes hyperspectral UAV imagery to acquire rice canopy data, applying various machine learning regression algorithms (MLR) to develop an LNC estimation model and create a nitrogen concentration distribution map, offering valuable guidance for subsequent field nitrogen management. The analysis incorporates four types of spectral data extracted throughout the rice growth cycle: original reflectance bands (OR bands), vegetation indices (VIs), first-derivative spectral bands (FD bands), and hyperspectral variable parameters (HSPs) as model inputs, while measured nitrogen concentration serves as the output. Results demonstrate that the random forest regression (RFR) and gradient boosting decision tree (GBDT) algorithms performed effectively, with the GBDT achieving the highest average R² of 0.76 across different nitrogen treatments. Among the nitrogen estimation models for various rice varieties, RFR exhibited superior accuracy, achieving an R² of 0.95 for the SuXiangJing100 variety, while the GBDT reached 0.93. Meanwhile, the support vector machine regression (SVMR) showed slightly lower accuracy, and partial least-squares regression (PLSR) was the least effective. This study developed an LNC estimation method applicable to the whole growth stage of common rice varieties. The method is suitable for estimating rice LNC across different growth stages, varieties, and nitrogen treatments, and it also provides a reference for nitrogen estimation and fertilization planning at flight altitudes other than the 120 m used in this study. Full article

(This article belongs to the Special Issue Unmanned Farms in Smart Agriculture)

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