Table of Content

12 November 2026, Volume 52 Issue 11

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REVIEW

Progresses and challenges in mining excellent genes of important traits in sweetpotato since the 14th five-year plan

Li Chen, Gao Run-Fei, Zhai Hong, Li Qiang

Acta Agronomica Sinica. 2026, 52(11):  3155-3165.  doi:10.3724/SP.J.1006.2026.64062

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Sweetpotato (Ipomoea batatas (L.) Lam.) is a globally important crop for food, feed, industrial raw materials, as well as functional foods. With the rapid development of biotechnology such as genomics, transcriptomics, metabolomics, and gene editing, significant progress has been made in exploring genes related to important traits in sweetpotato. The current status is systematically reviewed in mining excellent genes of seven key trait areas—yield and yield components, quality, biotic stress resistance, abiotic stress resistance, resource use efficiency, suitability for mechanization, and storage properties—both domestically and internationally since the 14th five-year plan. It focuses on summarizing the functions and molecular mechanisms of key genes controlling storage root formation and expansion, starch and sugar metabolism, anthocyanin and carotenoid biosynthesis, disease and pest resistance, drought and salt tolerance, and plant architecture regulation, and outlines the core challenges facing molecular biology research in sweetpotato. Finally, prospects for future molecular design breeding in sweetpotato are outlined. It is proposed to strengthen the integration of multi-omics and the application of gene editing technologies, construct high-precision genetic maps, deeply explore and utilize wild germplasm resources, and establish efficient breeding systems for pyramiding multiple traits. These efforts aim to accelerate the development of breakthrough sweetpotato varieties with high yield, superior quality, multi-resistance, suitability for mechanization, and resource use efficiency, thereby supporting the industry for sustainable development.

Research on mechanism of cold resistance of rapeseed

Chen Bi-Cong, Wei Jia-Ping, Zheng Guo-Qiang, Yan Yao-Ting, Liu Zi-Gang

Acta Agronomica Sinica. 2026, 52(11):  3166-3181.  doi:10.3724/SP.J.1006.2026.65009

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Rapeseed (Brassica napus L.) is one of the most important oilseed crops in China. Low-temperature stress is a major environmental factor limiting its productivity and geographical distribution and frequently causes significant reductions in yield and quality, resulting in considerable economic losses. This review evaluates the morphological, photosynthetic and physiological biochemical indicators of rapeseed’s cold tolerance, and systematically summarized the research progress on the cold tolerance mechanism of rapeseed, including aspects such as low-temperature signal perception, signal transduction, and the regulation of cold-response gene expression. Cold-tolerant rapeseed employs multiple defense mechanisms to cope with low-temperature stress. Efficient antioxidant systems help eliminate excessive reactive oxygen species (ROS), thereby reducing membrane lipid peroxidation and maintaining membrane stability. In addition, cold stress activates the ICE1-CBF-COR signaling pathway, in which CBF/DREB transcription factors induce the expression of downstream COR genes, leading to enhanced photosynthetic performance and antioxidant capacity. Moreover, the MAPK signaling cascade and stress-responsive genes, such as glutathione S-transferases (GSTs) related gene, play important roles in the regulation of cold adaptation. Collectively, these findings provide valuable insights into the molecular basis of cold tolerance in rapeseed and offer a theoretical foundation for the identification and utilization of elite cold-tolerant germplasm resources, the breeding of cold-resistant cultivars, and the development of effective frost-protection strategies.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Identification of novel QTL for plant height and internode length in wheat based on a 120K liquid-phase chip

Guan Pan-Feng, Ge Shuai, Wan Zi-Dong, Li Meng-Xin, Wang Xin-Yan, Lu Jia-Ling, Zhu Yu-Pan, Li Bing, Xu Hang-Bo, Ma Ruo-Nan, Jiao Zhen, Wei Wen-Hui, Cui Dong-Jie

Acta Agronomica Sinica. 2026, 52(11):  3182-3201.  doi:10.3724/SP.J.1006.2026.61035

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Plant height (PH) is a crucial agronomic trait that influences plant architecture and yield potential in wheat. An appropriate combination of PH and internode length (IL) not only enhances lodging resistance but also contributes to a higher harvest index, helping ensure high and stable yields. To further identify novel quantitative trait loci (QTL) controlling wheat PH and its components, a recombinant inbred line (RIL) population (AK58/ZYM2-RIL) comprising 183 lines was developed using the Chinese elite wheat variety Bainong Aikang 58 (AK58) as the maternal parent and the introduced variety Zhengyinmai 2 (ZYM2) as the paternal parent. A high-density genetic linkage map was constructed using the wheat 120K liquid-phase chip (120K-4HWA) genotyping data. Using phenotypic values from six field environments over three consecutive years, a genome-wide QTL analysis was conducted for PH and the five ILs in the AK58/ZYM2-RIL population. A total of 33 stable major QTL controlling PH and IL were detected on chromosomes 2D, 4B, 4D, 5A, 6A, 6B, and 7A, explaining 2.8% to 50.4% of the phenotypic variation. Among these, 24 allelic variations that reduced PH and IL originated from AK58. Additive effect analysis indicated that pyramiding favorable dwarfing alleles significantly reduced PH and each IL. The interactive functional gene discovery platform based on the wheat integrative regulatory network (wGRN) was used to predict candidate genes within stable major QTL intervals. A total of 25 potential candidate genes were identified, including the “Green Revolution” genes Rht1 and Rht2. Functional molecular markers were used to genotype Rht1, Rht2, and Rht8 within the intervals of QPh.zzu.4B.2, QPh.zzu.4D.1, and QPh.zzu.2D.2, respectively. The genetic effects of the Rht1 gene were verified using its near-isogenic lines, which were derived from a residual heterozygous line (RHL). Moreover, a kompetitive allele-specific PCR (KASP) marker was developed for the novel stable QTL QPh.zzu.5A.4/QIl2.zzu.5A.2 on chromosome 5AL controlling PH and IL for use in marker-assisted breeding. Overall, this study provides novel QTL and candidate genes for elucidating the genetic basis of wheat PH and its components, as well as functional molecular markers for breeding applications.

Physiological response mechanisms and comprehensive germplasm evaluation of salt-alkali tolerance in Tartary buckwheat (Fagopyrum tataricum) at the seedling stage

Huang Li-Xia, Zhao Min, Gu Meng-Yuan, Zhang Wei-Wei, Zhen Yi-Yue, Liu Long-Long, Ma Ming-Chuan, Liu Zhang, Xu Shi-Rui, Qin Lu-Jun, Zhang Li-Jun

Acta Agronomica Sinica. 2026, 52(11):  3202-3220.  doi:10.3724/SP.J.1006.2026.61036

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Soil salinization is a major abiotic stress that severely restricts buckwheat growth. To construct a comprehensive evaluation system for salt-alkali tolerance at the seedling stage and to screen elite germplasm, this study systematically compared the stress effects of neutral salts (NaCl, Na₂SO₄) and alkaline salts (NaHCO₃, Na₂CO₃). Seedlings of 160 buckwheat accessions were exposed to three concentrations of each salt. Fourteen agronomic traits and three physiological indicators—glycine betaine (GB), reactive oxygen species (ROS), and Na⁺/H⁺ antiporter (NHX)—were measured. Principal component analysis and the membership function method were used to calculate the comprehensive salt tolerance index (D-value). Cluster analysis and stepwise regression were then employed to construct an identification model, and the underlying physiological response mechanisms were investigated. Alkaline salts inhibited growth more severely than neutral salts, with the inhibitory effect ranked as Na₂CO₃ > NaHCO₃ > Na₂SO₄ ≈ NaCl. Principal component analysis extracted three principal components that cumulatively explained 76.40%-80.78% of the total variance. The first principal component (PC1, explaining 55.72%-59.65% of the variance) was dominated by root traits, including root fresh weight, root dry weight, and root projected area. Based on the D-value, cluster analysis classified the germplasm into five grades ranging from highly tolerant to extremely sensitive. Screening by agronomic traits alone identified seven accessions that consistently exhibited high tolerance across all four salt stresses. Integration of physiological indicators further identified five accessions that combined superior agronomic performance with physiological resistance. Stepwise regression generated a high-precision identification model (R² = 0.992-0.997, P < 0.01) and pinpointed nine core indicators for evaluating seedling salt-alkali tolerance: plant height, longest root length, stem diameter, shoot fresh weight, root fresh weight, root dry weight, root surface area, root volume, and leaf area. Physiological analysis revealed a “dynamic strategy switching” mechanism by which buckwheat adapts to different salt stresses. Under NaCl stress, tolerance was positively correlated with NHX content, whereas under Na₂SO₄ and alkaline salt stresses, it was significantly negatively correlated with ROS accumulation. Glycine betaine played distinct antioxidant regulatory roles under neutral versus alkaline salt stresses. This study established a comprehensive evaluation system for seedling salt-alkali tolerance in buckwheat, identified elite germplasm and core indicators, and provided a theoretical basis and valuable germplasm resources for elucidating salt-alkali tolerance mechanisms and for molecular breeding.

Gene mapping and cloning of a novel narrow-leaf mutant nal24 in rice

Zhao Rui-Tong, Li Yi-Lin, Zhou Wan-Feng, Fang Cheng, Zhang Dong-Yang, Shang Li-Jun, Cheng Wei-Min, Tao Liang-Zhi, Wu Yue-Jin, Wu Jian-Dong, Zhang Cong-He, Ye Ya-Feng, Liu Bin-Mei

Acta Agronomica Sinica. 2026, 52(11):  3221-3231.  doi:10.3724/SP.J.1006.2026.62009

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Rice leaf morphology is a key agronomic trait affecting photosynthetic efficiency and population yield. In this study, a stably inherited narrow-leaf mutant nal24 was obtained by heavy-ion beam irradiation mutagenesis of the japonica rice cultivar Wuyunjing 7 (wyj7). Compared with the wild type, the nal24 mutant exhibited a highly significant reduction in leaf width, accompanied by decreased plant height and increased tiller number. Histological analysis revealed that the narrow-leaf phenotype was caused by reduced numbers of large and small veins as well as reduced distances between small veins. Measurements of photosynthetic characteristics showed that the net photosynthetic rate of nal24 was markedly lower than that of the wild type under different light intensities, indicating reduced photosynthetic capacity. Genetic analysis demonstrated that this trait was controlled by a single recessive nuclear gene. The target gene NAL24 was finely mapped to a 77.6 kb physical interval on chromosome 1 via map-based cloning. Sequencing results identified a single base substitution (A→T) in LOC_Os01g02890, which encodes a phosphatidylserine synthase within this interval, cause the corresponding amino acid to undergo substitution. Knockout of this gene in wild-type plants using the CRISPR/Cas9 system produced a narrow-leaf phenotype, and genetic complementation restored wild-type leaf width. Transcriptional analysis indicated that the expression levels of multiple NAL family genes were significantly downregulated in the nal24 mutant, whereas the negative regulator of leaf width, WL1, was significantly upregulated. In conclusion, this study cloned the novel gene NAL24 that regulates rice vein development and leaf morphogenesis. The identification of this gene provides a theoretical basis and genetic resources for elucidating the molecular mechanisms underlying rice leaf shape formation.

Cloning and expression of the ClWRKY46 gene and its function in drought resistance in Coix L.

Wang Yu-Jiao, Wang Yong-Le, Lu Xian-Yong, Xu Da-Feng, Fu Yu-Hua, Zhu Jia-Bao

Acta Agronomica Sinica. 2026, 52(11):  3232-3247.  doi:10.3724/SP.J.1006.2026.64073

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The WRKY transcription factor family is widely involved in regulating plant responses to drought stress. Coix (Coix L.) is an important dual-purpose crop used for medicine and food, but its molecular mechanisms of drought tolerance have been relatively understudied. This study aimed to clone the ClWRKY46 gene from coix, analyze its sequence characteristics and expression patterns, and evaluate its stress response and tolerance under drought stress using heterologous expression systems, thereby providing a candidate gene and a theoretical basis for the genetic improvement of drought tolerance in coix. The ClWRKY46 gene was cloned using reverse transcription-polymerase chain reaction (RT-PCR), and its expression patterns in various tissues and under drought and salt stresses were analyzed. Protein localization and transcriptional activity were determined via subcellular localization and yeast transcriptional activation assays. Furthermore, drought tolerance phenotypes and physiological indicators were evaluated using yeast and Arabidopsis heterologous expression systems. The results showed that the cloned ClWRKY46 encodes a protein containing a typical WRKY domain, belonging to the Group III WRKY subfamily, and sharing the highest homology with rice OsWRKY45. The ClWRKY46 protein is localized in the nucleus and lacks transcriptional autoactivation activity in the yeast system. Drought stress significantly induced the upregulation of ClWRKY46 expression. Heterologous expression of ClWRKY46 in yeast significantly improved the survival rate of the strain under drought stress. Meanwhile, transgenic Arabidopsis lines overexpressing ClWRKY46 exhibited higher germination rates and superior growth performance under drought conditions, accompanied by significantly increased activities of antioxidant enzymes (SOD, POD, CAT) and a significant reduction in malondialdehyde (MDA) content. In conclusion, ClWRKY46 is a nuclear-localized transcription factor lacking autoactivation activity, which plays a positive regulatory role in drought stress responses. Heterologous expression demonstrated that this gene can significantly enhance the drought resistance of yeast and Arabidopsis.

Comprehensive analysis of the TIFY gene family and its potential roles in regulating leaf morphogenesis in Arachis hypogaea

Peng Zhen-Ying, Liu Meng-Ying, Li Lei-Lei, Meng Jing-Jing, Zhang Jia-Lei, Li Guo-Wei, Sui Na, Li Xin-Guo, Wan Shu-Bo

Acta Agronomica Sinica. 2026, 52(11):  3248-3263.  doi:10.3724/SP.J.1006.2026.65020

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The TIFY gene family plays crucial roles in plant development and responses to abiotic and biotic stresses. Genome-wide identification of TIFY members in peanut was combined with functional analysis and validation using a peanut leaf-curling mutant. A total of 30 AhTIFY genes were identified and assigned to the TIFY, PPD, ZML, and JAZ subfamilies. Among these, JAZ genes showed higher expression levels across various tissues, suggesting a more significant role in peanut tissue and organ development. Promoter analysis revealed a number of cis-elements associated with responses to light, drought, salicylic acid, and jasmonic acid. Protein interaction analysis indicated that AhJAZ proteins engage in extensive homomeric and heteromeric interactions and interact with transcription factors such as MYB and MYC. Transcriptomic comparison between normal plants and the leaf-curling mutant revealed significant differences in the expression patterns of genes related to hormone biosynthesis. Overexpression of AhJAZ8 and AhJAZ20 in Nicotiana benthamiana induced leaf curling, demonstrating the role of AhTIFY genes in leaf morphogenesis.

Identification and characterization of candidate genes for drought tolerance during the germination stage in Brassica napus L.

Yuan Rong, Du Yuan-Yuan, Hong Mei-Yan, Gao Jie, Huang Zhen, Li Ke-Qi, Zeng Xin-Hua

Acta Agronomica Sinica. 2026, 52(11):  3264-3278.  doi:10.3724/SP.J.1006.2026.65034

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Brassica napus is an important oilseed crop in China. Drought stress significantly inhibits its germination rate and seedling establishment, thereby causing yield loss. To comprehensively identify the genes underlying drought tolerance at the seed germination stage, we simulated drought stress using the PEG-6000 solution and evaluated 183 B. napus accessions for germination-stage drought tolerance. Phenotypic traits including germination rate (GR), germination potential (GP), germination index (GI), seedling percentage (SP), vigor index (VI), shoot fresh weight (SFW), root fresh weight (RFW), and root length (RL) were measured. A genome-wide association study (GWAS) identified nine significant SNP loci and 213 potential candidate genes. Furthermore, transcriptomic analysis of six accessions with contrasting drought tolerance revealed 13,251, 10,250, 10,455, 8968, 9990, and 16,706 differentially expressed genes (DEGs) under 0% and 15% PEG-6000 treatments, respectively. These DEGs were primarily enriched in drought-responsive KEGG pathways such as plant hormone signal transduction, plant-pathogen interaction, MAPK signaling pathway-plant, phenylpropanoid biosynthesis, and starch and sucrose metabolism. By integrating GWAS and RNA-seq data, we identified seven candidate genes associated with drought tolerance during seed germination. Among them, ZS11A03G038720, ZS11A09G011050, ZS11C02G013040, and ZS11C02G013790 were downregulated following PEG treatment, whereas ZS11A03G039060, ZS11C02G013640, and ZS11C02G013660 were upregulated. This study not only reveals key genetic loci underlying drought tolerance at the germination stage in B. napus, but also provides seven core candidate genes with potential value for molecular breeding of drought-tolerant rapeseed varieties, thereby offering genetic resources and theoretical insights for future improvement strategies.

Evaluation of stripe rust resistance and resistance genes in 81 major wheat cultivars from Gansu province, China

Zhang Bo, Huang Jin, Sun Zhen-Yu, Cao Shi-Qin, Li Pei-Ling, Li Qing-Qing, Guo Zhi-Jie, Wang Wan-Jun

Acta Agronomica Sinica. 2026, 52(11):  3279-3292.  doi:10.3724/SP.J.1006.2026.61030

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To understand the resistance of wheat cultivars grown in Gansu to wheat stripe rust and the stripe rust resistance genes they carry, this study evaluated 81 winter wheat cultivars from Gansu for resistance to wheat stripe rust at all growth stages and detected stripe rust resistance genes. The seedling-stage resistance evaluation results showed that 1.23% of the wheat cultivars were highly resistant to wheat stripe rust, 4.94% were moderately resistant, and 93.83% were moderately susceptible. The adult-plant resistance evaluation results from 2023 to 2024 indicated that 11.11% of the wheat cultivars were immune to wheat stripe rust, 8.64% were highly resistant, 8.64% were moderately resistant, 39.51% exhibited slow rusting, and 32.10% were moderately susceptible. The adult-plant evaluation results from 2024 to 2025 revealed that 7.41% of the wheat cultivars were immune to stripe rust, 7.41% were highly resistant, 38.27% were moderately resistant, 17.28% exhibited slow rusting, and 29.63% were moderately susceptible. The disease resistance gene detection results showed that the numbers of cultivars carrying the resistance genes Yr26/Yr24, Yr29/Lr46/Pm39/Sr58, Yr30/Lr27/Pm70/Sr2, Yr75, Yr78, Yr80, Yr82, YrSP/Yr5, Lr34/Yr18/Pm38/Sr57, Lr67/Yr46/Pm46/Sr55, and QYrsn.nwafu-2AS/Yr17 were 9, 77, 47, 18, 41, 11, 11, 3, 10, 81, and 17, respectively. All 81 wheat cultivars carried two or more resistance genes. The study indicated that the majority of wheat cultivars currently grown in Gansu were moderately susceptible at the seedling stage. At the adult-plant stage, they exhibited varying degrees of resistance to stripe rust, although some remained moderately susceptible. These cultivars carried a rich array of adult-plant resistance genes but lacked genes conferring resistance at all growth stages. Only effective pyramiding and interaction of resistance genes can enhance disease resistance in wheat.

SbCPP01 overexpression improves saline-alkali tolerance in Arabidopsis

Du Pin-Ting, Zhou Wei, Wang Zhen-Guo, Li Yan, Liu Xin-Yu, Zhang Shi-Qi, Wang Jin-Yue, Bao Xue-Lian, Zhou Ya-Xing

Acta Agronomica Sinica. 2026, 52(11):  3293-3307.  doi:10.3724/SP.J.1006.2026.64058

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The cysteine-rich polycomb-like protein (CPP) transcription factor plays a pivotal regulatory role in plant responses to stress conditions. Based on previous bioinformatics analysis of the CPP gene family in sorghum, combined with transcriptome data and RT-qPCR results, SbCPP01 was identified as a gene potentially involved in the response to saline-alkali stress. To verify the role of SbCPP01 in saline-alkali tolerance, we performed cloning and functional characterization of SbCPP01. The coding sequence of SbCPP01 was amplified via reverse transcription PCR, and an overexpression vector was constructed. The vector was subsequently introduced into Arabidopsis thaliana for functional assays. Under identical saline-alkali stress conditions, overexpression of SbCPP01 significantly improved the saline-alkali tolerance of transgenic Arabidopsis. Compared with wild-type plants, the transgenic lines showed higher germination rates, longer root lengths and greater fresh weight. Transgenic plants also exhibited higher activities of POD, SOD and CAT, along with increased contents of soluble protein, soluble sugar, starch and proline. By contrast, their levels of hydrogen peroxide (H₂O₂), superoxide anion (O₂^?) and malondialdehyde (MDA) were lower than those of the wild type. These findings indicate that SbCPP01 enhances antioxidant enzyme activities and alleviates reactive oxygen species accumulation. After 7 days of stress treatment, phenotypic observations revealed that wild-type seedlings suffered leaf yellowing and wilting, while transgenic lines grew well. RT-qPCR analysis further demonstrated that the expression levels of stress-responsive genes, including AtSOS1, AtSOS3, AtP5CS1, AtCBL10, AtLEA3, AtNHX1, AtRD29A and AtNCED3, were markedly upregulated in transgenic plants under saline-alkali stress. Collectively, overexpression of SbCPP01 confers enhanced saline-alkali tolerance in Arabidopsis thaliana. As a promising candidate gene for molecular breeding for saline-alkali resistance, SbCPP01 provides a theoretical basis and technical support for the genetic improvement of stress tolerance in sorghum and other crops.

Genome-wide identification of the AHL gene family in rice and phenotypic analysis of seed germination using CRISPR mutants

Chen Xiao-Bo, Liang Di-Yun, Li Hai-Bo, Zhao Zheng-Hao, Wang Bo

Acta Agronomica Sinica. 2026, 52(11):  3308-3317.  doi:10.3724/SP.J.1006.2026.62025

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AT-hook motif nuclear-localized (AHL) proteins are an ancient family of transcription factors involved in various essential biological processes in plants. In this study, genome-wide identification of the AHL gene family was performed in rice (Oryza sativa), followed by systematic analysis of gene structures, conserved motifs, promoter cis-acting regulatory elements, physicochemical properties, spatiotemporal expression patterns, and phylogenetic relationships. Furthermore, based on sequence homology, CRISPR/Cas9-mediated multiplex knockout lines were generated for members of this gene family. Preliminary screening and phenotypic analysis were conducted through seed germination and submergence-induced hypoxia assays. A total of 26 OsAHL genes were identified in the rice genome. Promoter analysis revealed various cis-acting elements associated with stress and phytohormone responses. Expression profiling showed that OsAHL genes were broadly expressed in the seed embryo and endosperm, with several members showing differential expression during anaerobic germination. Subsequent seed germination assays enabled the initial screening of 10 candidate gene sets associated with seed germination. Further submergence assays of the candidate lines successfully identified two gene sets associated with tolerance to hypoxic stress. In summary, this study systematically characterized the OsAHL gene family, established corresponding CRISPR/Cas9 knockout mutant resources, and identified candidate genes involved in seed germination and hypoxic stress responses, thereby providing an important genetic and material foundation for future mechanistic studies.

Drought resistance identification and comprehensive evaluation of peanut germplasm resources

Wu Shuai-Xia, Shang Sui-Teng, Yu Bing-Jie, Miao Hao-Cui, Wan Li-Yun, Hou Xian-Fei, Li Qiang, Jia Dong-Hai, Gu Yuan-Guo

Acta Agronomica Sinica. 2026, 52(11):  3318-3333.  doi:10.3724/SP.J.1006.2026.65013

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As a major abiotic stress, drought affects 40% of the world’s arable land and 60% of peanut-growing regions, resulting in a 20%-50% reduction in peanut yield. Systematically analyzing the phenotypic responses of peanut to drought stress and establishing a robust drought resistance evaluation system are of great theoretical and practical value for the development of the peanut industry. In this study, 384 peanut germplasm accessions were evaluated using a combination of field-based whole-growth-period drought stress and pot-based drought treatments. Agronomic traits were measured, and drought resistance was comprehensively assessed using the membership function method. The results showed that drought stress significantly reduced agronomic and yield traits at both the seedling stage and the whole growth period. The drought resistance coefficients of individual traits showed highly significant positive correlations with the comprehensive drought resistance value (D value) calculated by the membership function method. Based on cluster analysis of the D values, one highly drought-resistant germplasm accession (Puhua 9), five moderately drought-resistant accessions (GH01648, zy-496, GH01608, Yueyou 1821, Z5199), 37 moderately sensitive accessions (Heyou 11, Quanhonghua 1, W3701, zy-487, Z5189, etc.), and five sensitive accessions (Z5187, Z5223, zy-1097, Yuhua 144, Licheng Huasheng) were identified. Analysis of peanut germplasm accessions exhibiting substantial differences in overall performance revealed that reductions in main stem height, aboveground fresh weight, root fresh weight, and root dry weight can serve as indicators for drought resistance at the seedling stage, while decreases in main stem height, effective branch length, pod fresh weight, aboveground fresh weight, aboveground dry weight, pod yield per plant, and biomass per plant can be used as indicators for drought resistance throughout the entire growth period.

Preliminary study on the regulation of organ size and Sclerotinia sclerotiorum resistance by BnKIX8 in rapeseed (Brassica napus L.)

Luo Li-Ya, Ma Wu-Hui, Yang Long, Zhu Pei, Li Yan, Xu Ben-Bo, Zhang Xue-Kun, Xu Jin-Song

Acta Agronomica Sinica. 2026, 52(11):  3334-3351.  doi:10.3724/SP.J.1006.2026.65014

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In crop production, high-yield potential and disease resistance are often difficult to synergistically improve. Exploring the functions and molecular mechanisms of BnKIX8 homologous copies in the growth, development, and Sclerotinia sclerotiorum resistance of Brassica napus is therefore of great significance for the coordinated improvement of single-plant yield and disease resistance. In this study, Arabidopsis thaliana AtKIX8 was used as the reference gene to identify BnKIX8 homologous copies in B. napus, and their expression patterns were analyzed. CRISPR-Cas9 technology was used to generate loss-of-function mutants of BnKIX8s. Their functions were clarified by comparing agronomic traits and S. sclerotiorum resistance between homozygous mutants and wild-type plants, and the underlying molecular mechanisms were preliminarily explored through transcriptome analysis. The results were as follows: (1) Four homologous copies of BnKIX8 were identified in B. napus. BnKIX8.A7 and BnKIX8.C7 were expressed at all 18 sampling points, with high expression levels in siliques and seeds, whereas no expression of BnKIX8.A1 or BnKIX8.C1 was detected. (2) Homozygous T-DNA-free single mutants, bnkix8.a7 and bnkix8.c7, and the double mutant bnkix8.a7bnkix8.c7 were successfully obtained through CRISPR-Cas9-mediated gene editing. Phenotypic analysis showed that, compared with the wild type, the bnkix8s mutants had significantly increased flower size, silique length, seed size, and 1000-seed weight, as well as significantly higher seed germination and vigor indices. The double mutant showed an additive phenotype, indicating functional redundancy between BnKIX8.A7 and BnKIX8.C7 in regulating rapeseed growth and development. (3) Evaluation of S. sclerotiorum resistance showed that, at 36 h and 48 h post-inoculation, lesion areas in the bnkix8s mutants were significantly larger than those in the wild type, suggesting that BnKIX8.A7 and BnKIX8.C7 positively regulate resistance to S. sclerotiorum. (4) KEGG enrichment analysis of transcriptome data indicated that, under normal growth conditions, BnKIX8.A7 and BnKIX8.C7 may contribute to the growth-defense balance by influencing IAA and JA signal transduction pathways. At 24 h post-inoculation with S. sclerotiorum, BnKIX8.A7 and BnKIX8.C7 may participate in the resistance response by affecting α-linolenic acid metabolism and thiamine metabolism pathways. This study provides candidate pathways and genetic resources for further elucidating the functions of BnKIX8s and offers a theoretical basis for breeding high-yield and disease- resistant rapeseed varieties.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Effects of reduced tillage and no-tillage on photosynthesis and yield of double- cropped soybean in northern Xinjiang, China

Jiang Tao, Lu Jing-Jing, Ge Song-Hao, Zhai Ji-Peng, Ma Zi-Han, Chang Xiang-Mei, Xu Wen-Xiu, Su Li-Li, Tang Jiang-Hua

Acta Agronomica Sinica. 2026, 52(11):  3352-3365.  doi:10.3724/SP.J.1006.2026.65024

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This study aimed to investigate the effects of different no-tillage and reduced-tillage practices on photosynthate production and yield of double-cropped soybean in northern Xinjiang, and to identify suitable reduced-tillage and no-tillage practices for increasing yield in heavy clay soils in this region. A field experiment was conducted at the Sanping Teaching Practice Base of Xinjiang Agricultural University during 2024-2025. A split-plot design was adopted, with sowing method as the main-plot factor, including no-tillage sowing (NT) and no-tillage shallow loosening sowing (NTK). The subplot factor was intertillage frequency, consisting of three treatments: no intertillage (C0), one intertillage pass (C1), and two intertillage passes (C2). The results showed that, compared with no-tillage sowing, both no-tillage shallow loosening sowing and intertillage improved the SPAD value, dry matter accumulation, photosynthetic parameters, chlorophyll fluorescence characteristics, and yield of double-cropped soybean. Among all treatments, NTKC2 performed best. Over the two years, the mean SPAD value, net photosynthetic rate (P_n), transpiration rate (T_r), and peak dry matter accumulation under this treatment were 3.48%, 44.63%, 26.58%, and 37.80% higher, respectively, than those under traditional no-tillage sowing. These improvements effectively increased the number of seeds per plant. The two-year average yield reached 2989.10 kg hm^-2, which was 38.76% higher than that of the no-tillage sowing treatment. Results of Pearson correlation analysis and Mantel tests indicated that no-tillage shallow loosening sowing increased yield mainly by improving photosynthetic efficiency and photosystem performance, thereby promoting dry matter accumulation. Increasing intertillage frequency could also effectively enhance the operational efficiency of photosystem II and increase yield. These results indicate that no-tillage shallow loosening sowing combined with two intertillage passes is beneficial for improving the aboveground photosynthate production capacity of double-cropped soybean, delaying leaf senescence, promoting aboveground dry matter accumulation, and thereby achieving higher yield. This practice can serve as a suitable tillage and sowing method for double-cropped soybean in heavy clay soils in northern Xinjiang.

Effects of different nitrogen application methods on yield and fertilizer nitrogen fate of spring maize fields in the Loess Tableland

Li Jia, Lyu Shen-Qiang, Wang Jin-Feng, Wang Xiao-Fei, Yang Ze-Yu, Wang Lin-Quan

Acta Agronomica Sinica. 2026, 52(11):  3366-3375.  doi:10.3724/SP.J.1006.2026.63041

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This study investigated the effects of fertilizer application time and nitrogen (N) fertilizer type on spring maize yield and fertilizer N fate to provide a theoretical basis for rational nitrogen management in rain-fed spring maize on the Loess Tableland. A field experiment combining large plots and microplots was conducted from 2020 to 2022. Four large-plot treatments were established: (1) no N application (CK); (2) split-applied common urea (S-U, with 40% applied as basal fertilizer and 60% as topdressing at the ten-leaf stage (V10)); (3) a single basal application of common urea (B-U); and (4) a single basal application of matrix-based slow-release urea (B-SRU). In the microplots, the fate of N fertilizer was traced using ¹⁵N-labeled urea (10.14 atom%). For the split-applied N treatment, two additional microplot treatments were established, with ¹⁵N-labeled urea applied only as basal fertilizer (S-Ub_m) and only as topdressing (S-Ut_m). The N application rate for all fertilization treatments was 180 kg hm^-2. The results showed that the B-SRU treatment produced a higher yield, but the difference from the other N treatments was not significant; however, its economic benefit was 2338 yuan hm^-2 higher than that of S-U. There was no significant difference in total plant N accumulation among fertilization treatments during the whole growing season, but the stage-specific characteristics of the amount of plant N derived from fertilizer N (Ndff) varied with fertilization time and N fertilizer type. Compared with B-U_m, S-U_m significantly reduced pre-V10 Ndff by 53.7% and increased post-V10 Ndff by 63.2%; B-SRU_m decreased pre-V10 Ndff by 12.4% and increased post-V10 Ndff by 22.4%. In the split-application treatment, S-U_m plants derived N mainly from topdressed N, yet the first season ¹⁵N recovery efficiency (¹⁵NRE) of S-Ub_m was greater than that of S-Ut_m. Regarding fertilizer N fate, the first season ¹⁵NRE, residual rate, and loss rate of S-U_m were 29.7%, 49.6%, and 20.8%, respectively. The B-U_m treatment exhibited a first-season ¹⁵NRE similar to that of S-U_m, but significantly decreased the residual rate by 29.3%, increased the loss rate by 70.7%, and reduced the cumulative ¹⁵NRE by 18.5%. Compared with B-U_m, B-SRU_m increased the amount of soil ¹⁵N residue in the 0-20 cm layer by 31.4%, significantly increased the residual rate by 39.5%, decreased the loss rate by 26.7%, and enhanced the uptake of residual N by the succeeding crop, thus increasing the cumulative ¹⁵NRE by 7.4%. In conclusion, a single basal application of matrix-based slow-release urea can maintain yield while effectively improving economic benefit and reducing the N loss rate for rain-fed spring maize on the Loess Tableland. This practice is recommended as an appropriate fertilization strategy for simplified and labor-saving spring maize cultivation in this region.

Analysis of photosynthetic performance of the boll-leaf system during single boll weight formation in sea-island cotton (Gossypium barbadense L.) with different fruiting branch types

Li Xue-Jiao, Yan Peng, Zhao Jia-Bing, Zhou Jing-Kun, Wei Zhang, Liang Fu-Bin, Wang Yu-Xuan, Tian Jing-Shan, Jiang Chuang-Dao, Zhang Wang-Feng

Acta Agronomica Sinica. 2026, 52(11):  3376-3392.  doi:10.3724/SP.J.1006.2026.64026

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Sea-island cotton (Gossypium barbadense L.) has slender fibers with high strength, serving as a crucial raw material for high-grade and specialty cotton textiles. Xinjiang is the only production area of sea-island cotton in China. However, compared with upland cotton (Gossypium hirsutum L.), sea-island cotton has a relatively low yield, resulting in declining economic competitiveness and a continuous reduction in its planting area in recent years, severely affecting the effective supply of high-quality cotton in China. Therefore, it is of great practical significance to elucidate the yield formation mechanism and clarify the technical approaches for yield improvement. Under current cultivation conditions, sea-island cotton sets more bolls per plant than upland cotton, but its single boll weight is far lower. Hence, increasing single boll weight is the key to improving yield. Nevertheless, the physiological mechanisms underlying single boll weight formation and the approaches to its regulation remain unclear. From the perspective of the boll-leaf system at the single fruiting branch level (including main-stem leaves, sympodial leaves, cotton bolls and other non-leaf organs), this study compared the photosynthetic performance, dry matter accumulation and distribution characteristics of the boll-leaf system among sea-island cotton (nulliplex and normal branch cultivars) and the widely planted upland cotton cultivar (normal branch type). The two-year experimental results showed that, compared with upland cotton, the single boll weights of nulliplex and normal branch sea-island cotton were 43.0% and 49.5% lower, respectively; the net photosynthetic rates of the boll-leaf system were 22.2% and 29.1% lower, and leaf areas were 24.0% and 13.5% lower, respectively, indicating insufficient photosynthetic capacity of the boll-leaf system in sea-island cotton. Analysis of dry matter accumulation dynamics revealed that the maximum dry matter accumulation rates of cotton bolls in nulliplex and normal branch sea-island cotton reached 65.5% and 51.5% of those in upland cotton, respectively, and the rapid accumulation periods were shortened by 2-3 days in both types. Regarding dry matter distribution, the boll shell proportion in the two sea-island cotton types was 10.9% and 5.4% higher than that in upland cotton, respectively, indicating a lower proportion of photoassimilates partitioned to seeds and fibers. In addition, the main-stem leaves of nulliplex branch sea-island cotton continued to grow after anthesis, competing for photoassimilates with cotton bolls, which further restricted dry matter accumulation within the bolls. Collectively, the low photosynthetic rate of the boll-leaf system is a common limiting factor for the low single boll weight in sea-island cotton; however, improvement strategies should differ depending on the principal limiting factor in each branch type: for nulliplex branch sea-island cotton, alleviating nutrient competition between main-stem leaves and bolls after anthesis is critical, whereas for normal branch sea-island cotton, the priority should be to enhance the photosynthetic capacity of sympodial leaves. These findings provide a theoretical basis for high-yield breeding and agronomic regulation targeting single boll weight improvement in sea-island cotton.

Effects of combined application of ARC microbial agent and chemical fertilizer on photosynthetic pigment contents, nutrient allocation, and peanut yield

Zhang Ming-Tao, Li Zi-Wen, Gao Ming-Xuan, Liu Ming-Ze, Sun Yu-Han, Meng Tian-Yi, Zhang He, Wang Jing, Jiang Chun-Ji, Liu Xi-Bo, Wang Xiao-Guang, Zhang Liang-Xiao, Li Pei-Wu, Yu Hai-Qiu, Zhao Xin-Hua

Acta Agronomica Sinica. 2026, 52(11):  3393-3405.  doi:10.3724/SP.J.1006.2026.65017

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Peanut (Arachis hypogaea L.) is an important oilseed and cash crop worldwide. The Aflatoxin-Rhizobium Complex (ARC) microbial agent is effective in controlling aflatoxin contamination and enhancing nitrogen fixation via root nodules in legume crops, whereas the physiological mechanism by which the ARC microbial agent increases peanut yield and reduces fertilizer use remains unclear. In this study, ‘Huayu 39’ was used in field trials at Shenyang Agricultural University during the 2023-2024 growing seasons. Seven treatments were set: full fertilization (600 kg hm^-2, N-P₂O₅-K₂O = 14-16-15, CK), full fertilization combined with the ARC microbial agent (600 kg hm^-2 + 30 kg hm^-2, T0), 10% reduction in fertilizer combined with the application of the ARC microbial agent (540 kg hm^-2 + 30 kg hm^-2, T1), 25% reduction in fertilizer combined with the application of the ARC microbial agent (450 kg hm^-2 + 30 kg hm^-2, T2), 40% reduction in fertilizer combined with the application of the ARC microbial agent (360 kg hm^-2 + 30 kg hm^-2, T3), 55% reduction in fertilizer combined with the application of the ARC microbial agent (270 kg hm^-2 + 30 kg hm^-2, T4), and no fertilizer or microbial agent applied (T5), to systematically investigate the effects of different chemical fertilizer application rates combined with the ARC microbial agent on biomass accumulation per peanut plant, photosynthetic pigments, nutrient uptake and utilization, fertilizer utilization efficiency, and yield. The results indicated that a moderate reduction in chemical fertilizer application, combined with the application of the ARC microbial agent, significantly modulated the growth and physiological characteristics of peanut plants, optimizing plant biomass production and nutrient use efficiency. During the flowering-pegging stage, the chlorophyll a and chlorophyll b contents in leaves under T1 were significantly higher than those in CK by 6.49% and 8.85%, respectively, whilst the carotenoid content under T1 and T2 was significantly higher than that in CK by 54.11% and 29.74%, respectively (P < 0.05). During the pod-setting and pod-filling stages, the activities of glutamate synthase (GOGAT), nitrate reductase (NR), glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in leaves under T1 increased by 12.24%-38.80%, 29.78%-94.37%, 10.75%-59.37% and 34.53%-74.90% compared with CK. During the pod-setting stage, under the T1 treatment, the accumulation of nitrogen, phosphorus and potassium in plants increased significantly by 4.75%, 68.09% and 46.87%, respectively, compared with CK (P < 0.05), whilst under T2, phosphorus and potassium accumulation in plants increased significantly by 21.83% and 25.05%, respectively (P < 0.05). Furthermore, the biomass per peanut plant under T1 and T2 increased significantly by 47.41% and 17.22%, respectively, compared with CK (P < 0.05). Moderately reducing chemical fertilizer application and combining this with the application of the ARC microbial agent optimized the pattern of nutrient allocation among plant organs, thereby promoting the transport and accumulation of nutrients in the pods. In 2023 and 2024, the agronomic efficiency of the T0 treatment was significantly higher than that of CK by 10.79%-29.52%. Analysis of yield composition showed that, compared with the control (CK), the number of pods per plant and the weight of 100 pods were both significantly higher in the T0, T1 and T2 treatments; yields in 2024 were significantly higher than those of the control by 4.88%, 12.66% and 6.65%, respectively. In summary, a moderate reduction in chemical fertilizer application (450 kg hm^-2 to 540 kg hm^-2) combined with the application of 30 kg hm^-2 of the ARC microbial agent (T1, T2) synergistically enhanced peanut yield by improving nitrogenase activity, promoting plant biomass accumulation and nitrogen metabolism and utilization, thereby achieving both stable yields and economic efficiency. The findings of this study provide theoretical and technical support for reducing chemical fertilizer application and promoting sustainable peanut production.

Responses of leaf physiological and biochemical characteristics to exogenous abscisic acid application under drought stress: a meta-analysis

Du Xiang-Bing, Li Wang-Cheng, Zhao Zi-Bo, Lyu Hang, He Lei, Li Jia-Wen

Acta Agronomica Sinica. 2026, 52(11):  3406-3419.  doi:10.3724/SP.J.1006.2026.64004

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Exogenous abscisic acid (ABA) is a key hormone regulating crop drought resistance; however, a quantitative and systematic evaluation of its effects under drought stress remains lacking. In this study, a meta-analysis was conducted using 321 paired observations from 70 published studies worldwide to quantitatively characterize the regulatory effects of exogenous ABA on leaf physiological and biochemical traits in crops under drought stress, including relative water content (RWC), chlorophyll content (Chl), stomatal conductance (G_s), malondialdehyde (MDA), and hydrogen peroxide (H₂O₂). A random forest model was employed to identify potentially important moderators, and regression analysis combined with subgroup analysis was further applied to validate their importance. The results showed that, compared with the drought-stressed control, exogenous ABA application significantly increased leaf RWC (effect size I = 10.45%, P < 0.05) and Chl content (I = 14.60%), and significantly decreased G_s (I = -11.44%), MDA (I = -17.94%), and H₂O₂ content (I = -10.74%). The random forest model identified treatment duration, soil relative water content, ABA concentration, application method, and crop type as potentially important moderators of ABA effects, with treatment duration having the highest relative importance for RWC and Chl, at 32.6% and 36.3%, respectively. Regression analysis further revealed significant concentration-dependent responses of RWC, Chl, MDA, and H₂O₂ to exogenous ABA; the promoting effect on RWC was significantly positively correlated with soil RWC, while the regulatory effect on H₂O₂ was significantly time-dependent (P < 0.05). Overall, rational application of exogenous ABA under drought stress can effectively improve leaf water status and photosynthetic performance while alleviating oxidative damage in crops. These effects can be synergistically regulated by optimizing ABA application strategies in combination with field management practices. This study provides a quantitative reference for the regulation of crop leaf physiological and biochemical responses by exogenous abscisic acid under drought stress.

Effects of nitrogen application rates on forage production, nitrogen use efficiency, and greenhouse gas emission intensity in a silage maize-lablab intercropping system

Zhang Yi-Yin, Wang Hai-Xia, Zhao Meng-Yu, Wang Teng-Fei, Ma Jiang-Ping, Wang Bin, Lan Jian

Acta Agronomica Sinica. 2026, 52(11):  3420-3433.  doi:10.3724/SP.J.1006.2026.63044

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To clarify the response characteristics of forage yield, nutritional quality, nitrogen utilization, and greenhouse gas emissions in silage maize-lablab intercropping under different nitrogen application rates, and to provide a theoretical basis for high-yield, high-efficiency, and green production of high-quality forage in irrigated areas of Northwest China, a split-plot experiment was conducted in the oasis irrigation area of Northwest China from 2023 to 2024. The main plots consisted of two planting patterns: silage maize monocropping (SM) and silage maize-lablab intercropping (ML). The subplots consisted of five nitrogen application rates: N₀ (0 kg hm^-2), N₇₅ (75 kg hm^-2), N₁₅₀ (150 kg hm^-2), N₂₂₅ (225 kg hm^-2), and N₃₀₀ (300 kg hm^-2). System dry matter yield, nutritional quality, nitrogen uptake and use efficiency, and greenhouse gas emission intensity were measured, and structural equation modeling was used to analyze the relationships among these factors. The results showed that both nitrogen application and intercropping significantly improved forage yield and nutritional quality. Compared with monocropping under the same nitrogen application rate, intercropping increased system dry matter yield and crude protein yield by 18.68% and 30.85%, respectively, and increased crude protein content, total digestible nutrients, and relative feeding value by 19.81%, 8.47%, and 11.35%, respectively. Yield in the monocropping system peaked under N₃₀₀, whereas that in the intercropping system peaked under N₂₂₅. In addition, under the N₇₅-N₃₀₀ treatments, compared with monocropping, intercropping increased crude protein content, total digestible nutrients, and relative feeding value by 18.30%-24.51%, 7.02%-10.61%, and 9.49%-12.70%, respectively. Under the same nitrogen application rate, greenhouse gas emission intensities based on dry matter yield and crude protein yield were reduced by 8.51%-20.03% and 13.87%-29.08%, respectively, in the intercropping system compared with monocropping. Structural equation modeling revealed that nitrogen application and planting pattern promoted yield formation and forage quality improvement mainly by increasing LAI and nitrogen uptake. Nitrogen uptake was the key factor driving dry matter yield improvement. Greenhouse gas emission intensity per unit yield increased significantly under excessive nitrogen application, whereas appropriate nitrogen application achieved relatively low emissions while increasing yield. Overall, silage maize-lablab intercropping combined with a nitrogen application rate of 225 kg hm^-2 significantly improved forage yield, nutritional quality, and nitrogen use efficiency, while effectively reducing greenhouse gas emission intensity. Therefore, it can be recommended as a suitable production pattern for high-yield, high-efficiency, and green production of high-quality forage in irrigated areas of Northwest China.

Analysis of precipitation, water demand, and water surplus/deficit characteristics during the growth period of summer maize in the mid-altitude plateau region of Yunnan province, China

Guo Song, Wang Dan, Yu Ming-Yong, Li Qiu-Zhuo, Yang Zheng-Nan, Tian Jin-Yu, Qi Si-Qi, Jiang Ge, Duan Xue-Mei, Zhang Jia-Yun, Li Meng

Acta Agronomica Sinica. 2026, 52(11):  3434-3448.  doi:10.3724/SP.J.1006.2026.63029

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Understanding the water supply and demand characteristics of summer maize in the mid-altitude plateau region of Yunnan Province is critical for drought prevention and water management under climate change. Based on daily meteorological data from 1959 to 2023, this study used the crop coefficient method to analyze interannual trends and differences in water supply and demand across different growth stages, as well as variations at the 10-day, or dekad, scale. A water surplus/deficit index was used to assess drought and waterlogging risks at different levels. The results showed that: (1) Over the entire growing season, precipitation and effective precipitation decreased significantly by 25.25 mm and 9.06 mm per decade, respectively, particularly during the tasseling-maturity stage. Water demand showed no significant trend, except for a decrease of 0.78 mm per decade during the milk-maturity stage. Consequently, the supplemental irrigation requirement increased by 7.80 mm per decade over the whole season. (2) At the dekad scale, both precipitation and effective precipitation showed a unimodal distribution, peaking in late June and late July, respectively. Water demand peaked from early June to late July, exceeding precipitation and resulting in a mismatch between water supply and demand, with supplemental irrigation requirements of 12.35-19.27 mm. (3) Across the main growth stages, precipitation and effective precipitation first increased and then decreased, reaching their maxima during the jointing-tasseling and tasseling-milk stages, respectively. Water demand was highest during the jointing-tasseling stage and lowest during the milk-maturity stage. As a result, a net water deficit requiring 114.08 mm of supplemental irrigation occurred from sowing to milk stage, whereas the milk-maturity stage showed a water surplus of 21.68 mm, indicating a need for drainage. (4) The water surplus/deficit index indicated a high probability of suitable water conditions over the whole growing season (0.80). However, drought was highly likely during the sowing-emergence stage (0.65), water conditions were relatively suitable from emergence to milk stage (0.58-0.73), and waterlogging was likely during the milk-maturity stage (0.50). These findings provide a scientific basis for targeted drought mitigation, drainage management, and efficient water regulation for summer maize production in this region.

RESEARCH NOTES

Development of an alkali tolerance phenotyping method for soybean at the emergence stage and screening of alkali- and salt-tolerant germplasm accessions

Xue Wen-Hao, Wang Xin-Ru, Wang Meng-Chen, Chang Ru-Zhen, Guan Rong-Xia, Qiu Li-Juan

Acta Agronomica Sinica. 2026, 52(11):  3449-3463.  doi:10.3724/SP.J.1006.2026.65038

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Soil alkalization is one of the major abiotic stresses restricting soybean growth, development, and yield. Developing efficient evaluation methods for soybean alkali tolerance and screening alkali-tolerant germplasm resources is crucial for improving soybean productivity on sodic soils. In this study, vermiculite was used as the seedling substrate, and gradient treatments were conducted with mixed alkali solutions (0, 30, 35, and 40 mmol L^-1 NaHCO₃:Na₂CO₃ = 9:1, molar ratio). By comparing aboveground and belowground phenotypic traits including plant height, leaf area, root length, and root volume, we aimed to identify suitable evaluation indices and establish an efficient evaluation method for alkali tolerance at the soybean emergence stage. The results showed that treatments with 35 mmol L^-1 and 40 mmol L^-1 mixed alkali solutions significantly inhibited the aboveground growth and root development of soybean seedlings, with significant phenotypic differences observed among the tested germplasm accessions. Correlation analysis indicated that relative leaf area was significantly correlated with multiple root traits and could reliably reflect the alkali tolerance of different accessions. Ultimately, 35 mmol L^-1 mixed alkali solution was selected as the treatment concentration. The relative leaf area measured 10 days after alkali treatment was defined as the alkali tolerance coefficient (ATC), which served as the evaluation index for soybean alkali tolerance at the emergence stage. This method was used to evaluate the alkali tolerance of 52 soybean germplasm accessions, which were classified into four grades according to ATC values. Twelve grade 1 highly alkali-tolerant accessions and ten grade 2 alkali-tolerant accessions were identified. Meanwhile, salt tolerance identification at both emergence and seedling stages was carried out on all 52 accessions. Three elite soybean accessions, namely SZH101, DND254, and SN33, were finally identified. These accessions exhibited both alkali and salt tolerance at the emergence stage and stable salt tolerance at the seedling stage. This study presents a simple, non-destructive, and high-throughput method for evaluating alkali tolerance in soybean at the emergence stage, which is highly valuable for efficient identification of alkali-tolerant soybean germplasm, mining of key alkali-tolerance genes, and accelerated breeding of alkali-tolerant varieties.

Effects of water-nitrogen interactions on post-anthesis photosynthetic characteristics and carbon metabolism in Jigu 22

Qin Ling, Zhang Meng-Yuan, Xu Feng, Li Fei-Fei, Liu Chang-Hong, Chen Er-Ying, Yang Yan-Bing, Guan Yan-An

Acta Agronomica Sinica. 2026, 52(11):  3464-3474.  doi:10.3724/SP.J.1006.2026.64038

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To investigate the effects of different water and nitrogen treatments on post-anthesis photosynthetic characteristics, carbon metabolism, and yield of foxtail millet, a pot experiment was conducted using Jigu 22 as the test material. The experiment included two nitrogen treatments, N0 (no nitrogen application) and N150 (150 kg hm^-2), and three water treatments, CK (normal irrigation), W1 (drought from the seedling to jointing stage), and W2 (drought from heading to the middle grain-filling stage). During drought periods, the relative soil water content was maintained at 30%-40%, whereas it was maintained at 60%-70% during non-drought periods. Photosynthetic characteristics, dry matter accumulation and translocation, starch and sucrose contents, and related enzyme activities of foxtail millet were measured. The results showed that SPAD value and net photosynthetic rate (P_n) under different water and nitrogen treatments gradually decreased as growth progressed, while nitrogen application significantly increased post-anthesis SPAD and P_n. Grain starch content continued to increase after anthesis, whereas starch contents in leaves and stem sheaths decreased. Nitrogen application reduced starch content in all organs, with the greatest decrease, 21.50%, observed in panicles at 40 days after anthesis. Sucrose content in all organs first increased and then decreased and was highest under W2 with nitrogen application. Meanwhile, nitrogen application enhanced the activities of sucrose-metabolizing enzymes, including SPS, SS-I, and SS-II, whereas W2 suppressed SS-I activity but increased SPS and SS-II activities during 0-20 days after anthesis. Nitrogen application significantly increased post-anthesis dry matter accumulation in vegetative organs and its contribution to grain yield, while reducing the contribution of pre-anthesis reserves. The W1 treatment promoted post-anthesis dry matter accumulation and translocation, whereas the W2 treatment relied mainly on pre-anthesis reserves. The W1N150 treatment achieved the highest grain yield, grain weight per panicle, and thousand-grain weight, which were 14.85%, 9.52%, and 3.18% higher than those under CKN150, respectively. In summary, moderate drought at the seedling stage combined with nitrogen application (W1N150) increased foxtail millet yield by improving P_n, promoting post-anthesis dry matter accumulation and translocation, and enhancing carbon metabolism and sucrose synthesis capacity, thereby providing a theoretical basis for water- and nitrogen-saving cultivation practices.