Table of Content

12 September 2026, Volume 52 Issue 9

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REVIEW

Optimization of plant protoplast preparation and application challenges of SC-ICP-MS

Jia Meng-Chen, Wang En-Hui, Yu Xiao-Jing, Li Shun, Bai Li-Yong, Dai Jiu-Lan

Acta Agronomica Sinica. 2026, 52(9):  2535-2548.  doi:10.3724/SP.J.1006.2026.53100

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Single cell-inductively coupled plasma-mass spectrometry (SC-ICP-MS) can accurately analyze the element distribution in plant tissues at the single-cell level. This technology can explore the cell heterogeneity ignored by traditional population analysis methods, significantly improve the spatial resolution of elemental analysis, and provide a new way for elemental quantification. However, SC-ICP-MS determination technology is limited by the acquisition of high-quality cell suspension and accurate elemental analysis. Current studies have shown that the preparation of high-quality protoplasts is a critical prerequisite for the application of this technology. Therefore, the establishment of an efficient and stable plant protoplast preparation method directly determines the sensitivity, quantitative accuracy and repeatability of SC-ICP-MS detection, which has become a prerequisite for restricting the application of this technology. In this review, the preparation process of common plant protoplasts and their core adaptation principles to SC-ICP-MS were introduced, including source tissue selection, pretreatment, optimization of enzymatic hydrolysis system (ratio of enzymatic hydrolysate, digestion time, osmotic pressure regulation and addition of auxiliary substances), protoplast purification, vitality detection, and chemical fixation. The cell-level research on nutrients and heavy metals was summarized as well as the parameter optimization strategies of SC-ICP-MS were summarized. This technique is still faced with challenges in a proper balance between cell integrity and element retention, besides the possibility of accounting for the toxicity effects, uptake, and biological effects of exogenous substances. Future research should combine imaging, omics and other technologies to explore the metabolic process of elements, and further promote the application of SC-ICP-MS detection in agriculture, environment, ecology and life sciences.

CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS

Mapping and molecular marker development of QTL for wheat grain length under drought stress

Chen Jia, Sun Dai-Zhen, Li Chao-Nan, Li Long, Jing Rui-Lian, Yang Jin-Wen, Wang Jing-Yi

Acta Agronomica Sinica. 2026, 52(9):  2549-2558.  doi:10.3724/SP.J.1006.2026.61018

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Drought stress during the grain filling period severely impacts grain development in common wheat. Grain traits such as grain length and grain width are closely associated with yield. However, genetic dissection of these traits under drought stress is significantly insufficient. In this study, a BC₃F₄ backcross introgression line population derived from drought-tolerant cultivar Jinmai 47 and drought-sensitive cultivar Yumai 13 was employed to identify important genetic loci controlling grain length under drought stress via BSA-seq analysis. A QTL significantly associated with grain length under drought stress was detected on chromosome 1D within the 432.65-460.02 Mb interval and was designated GLd1. The GLd1 was consistently detected in three additional backcross introgression line populations. Molecular markers were developed based on sequence polymorphisms between Jinmai 47 and Yumai 13 within the GLd1 interval, further narrowing the candidate interval to 1.01 Mb. Using the KASP marker 1D-SNP57 developed within the GLd1 interval, genotype-phenotype association analysis was conducted in a natural wheat population consisting of 325 accessions. Genotypes carrying the Jinmai 47 allele exhibited significantly longer grains than those carrying the Yumai 13 allele, confirming the close association of this marker with grain length under drought stress. This study identifies a novel QTL for grain length under drought stress in wheat and provides a KASP marker applicable for grain length selection, offering new genetic resources and practical tools for breeding drought-tolerant and yield-stable wheat varieties.

Genome-wide association study of nitrogen use efficiency and candidate gene mining in maize

Huang Ying, Liu Pei-Qi, Xie Sen, Xu Luo, Ren Yuan, Liu Xu-Yang, He Guan-Hua, Li Yong-Xiang, Wang Tian-Yu, Li Yu, Zhou Tao, Liao Jiang-Lin, Li Chun-Hui, Zhang Deng-Feng

Acta Agronomica Sinica. 2026, 52(9):  2558-2572.  doi:10.3724/SP.J.1006.2026.63028

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Nitrogen is a key factor influencing maize yield. To dissect the genetic basis of nitrogen response in maize, this study utilized a natural population consisting of 312 maize inbred lines and employed genome-wide association analysis (GWAS) on the nitrogen response index (NRI) of yield-related traits. The results indicated that yield-related traits exhibited abundant phenotypic variation under both nitrogen conditions. Significant differences in nitrogen response index of grain yield (NRI_GY) and grain yield were observed among different heterotic groups; compared with other groups, the Iodent group displayed the highest NRI_GY, while the SPT group exhibited the strongest low-nitrogen tolerance. Genome-wide association analysis identified a total of 1582 significant loci associated with NRI, of which 352 loci were located within the confidence intervals of previously reported nitrogen-efficient QTLs. These significantly associated loci comprised 372 candidate genes, primarily involved in maize growth, development, and stress responses. Haplotype analysis of key candidate genes revealed that, the TT haplotype of Zm00001d021701 had a lower nitrogen response coefficient for kernel number per row than CC, but exhibited higher yield than CC under both normal and low nitrogen conditions; the AA haplotype of Zm00001d037229 had a higher nitrogen response coefficient for ear height than GG, and outperformed GG in yield under both nitrogen levels. This study systematically elucidated the genetic architecture of nitrogen response in maize, and the identified key candidate genes along with their elite haplotypes provide important genetic resources and theoretical support for molecular breeding of nitrogen-efficient maize varieties.

GWAS analysis of low potassium tolerance trait at seedling stage in sweetpotato and screening of candidate genes

Liu Ming, Lin Lin, Yu Yong-Chao, Jin Rong, Zhao Peng, Zhang Qiang-Qiang, Zhu Xiao-Ya, Wang Jing, Li Shuo, Tang Zhong-Hou

Acta Agronomica Sinica. 2026, 52(9):  2573-2583.  doi:10.3724/SP.J.1006.2026.64016

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Sweetpotato is a typical “potassium (K⁺)-loving” crop. Exploring genetic resources of low-K⁺-tolerance and elucidating the underlying mechanisms in sweetpotato are important strategies to address soil potassium deficiency and the shortage of potassium resources. This study aimed to screen candidate genes associated with low-K⁺ tolerance in sweetpotato through genome-wide association analysis (GWAS), providing a reference for breeding low-K⁺-tolerant varieties and mining genes for efficient K⁺ utilization. A total of 213 sweetpotato varieties (lines) were subjected to hydroponic experiments under low-K⁺ stress (0.1 mmol L^-1 K⁺) and normal K⁺ treatment (10.0 mmol L^-1 K⁺). Traits including biomass, K⁺ content, K⁺ accumulation, K⁺ use efficiency, and relative growth rate were collected for GWAS. Results showed that six traits—dry biomass, fresh biomass, relative growth rate, shoot K⁺ accumulation, root K⁺ accumulation, and whole plant K⁺ accumulation—were significantly or extremely significantly correlated with each other. Through GWAS, seven genomic segments associated with five traits (relative growth rate, shoot K⁺ content, root K⁺ accumulation, plant K⁺ accumulation, and dry biomass) were identified, containing a total of 35 SNP loci. Based on core SNP loci and gene function annotation, 7 candidate genes related to low-K⁺-tolerance in sweetpotato were predicted. RT-qPCR verification discovered that three candidate genes, itf12g23740.t1, itf08g06140.t1, and itf08g06320.t1- encoded cation/H⁺ exchanger 15 (CHX15), auxin receptor F-box protein 5 (AFB5), and vernalization-insensitivity 3-like 1 (VIL1), respectively, showed expression differences among varieties with contrasting low-K⁺-tolerance. Overall, a total of 35 significant SNP loci associated with low-K⁺ tolerance traits were detected in the 213 sweetpotato accessions, and seven candidate genes were predicted. Among them, itf12g23740.t1, itf05g03220.t1, and itf08g06140.t1 are important candidate genes for low-K⁺ tolerance in sweetpotato and warrant further investigation.

Meta-analysis of QTL for yield-related traits in upland cotton and identification of candidate genes

Zhao Yan, Zhang Wen-Jiao, Yang Qi-Wen, Wei Jia-Zhi, Yu Xiao-Xue, Li Dan-Dan, Wei Chu, Feng Yu-Yu, Peng Jia-Luo, Wang Cai-Xiang, Ma Xiong-Feng, Su Jun-Ji

Acta Agronomica Sinica. 2026, 52(9):  2584-2597.  doi:10.3724/SP.J.1006.2026.54159

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Yield is one of the primary target traits in the genetic improvement and variety breeding of upland cotton (Gossypium hirsutum L.). Mapping quantitative trait loci (QTLs) related to yield and mining candidate genes is of great significance for enhancing cotton yield potential through molecular breeding. Integrating reported QTLs to identify stable and major-effect QTLs and candidate genes controlling yield-related traits in upland cotton serves as the foundation and key for molecular improvement of cotton yield traits. In this study, based on 42 independent studies, a total of 3366 original QTLs related to 11 yield-related traits were collected. Using 11,242 markers, a consensus genetic map was constructed, onto which 2751 of the original QTLs were projected, leading to the identification of 209 Meta-QTLs (MQTLs) for yield traits. Among these, 61 MQTL regions were validated by significant SNP loci from genome-wide association studies (GWAS). Within these GWAS-co-localized MQTLs, a major-effect MQTL (MQTL6) was identified with the highest phenotypic variation explained (R²) of 18.36%, integrating 24 original QTLs and a confidence interval (CI) narrowed down to 2.7 cM. Combining transcriptome sequencing (RNA-seq) and real-time quantitative PCR (RT-qPCR) analyses, two candidate genes closely related to yield, GhEB1C and GhHIPP23, were screened from the MQTL6 interval. Through virus-induced gene silencing (VIGS) validation, it was found that GhEB1C primarily regulates seed and boil development, whereas GhHIPP23 simutaneously regulates seed development and lint percentage formation, indicating that both play key regulatory roles in in yield formation in upland cotton. These findings provide new insights into the genetic mechanisms underlying yield traits in upland cotton and offer candidate gene resources for molecular breeding of high-yielding cotton varieties.

Mapping of genes-related to sucrose content in peanut and development and validation of KASP markers in peanut

Pan Li-Juan, Jiang Xiao, Xu Jing, Yin Xiang-Zhen, Wan Fei-Fei, Sun Shu-Juan, Zhao Xu-Hong, Chen Na, Ma Jun-Qing, Chi Xiao-Yuan

Acta Agronomica Sinica. 2026, 52(9):  2598-2607.  doi:10.3724/SP.J.1006.2026.65005

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In this study, an F₂ segregation population derived from a cross between the high-sucrose peanut variety "Jihuatian 1" and the low-sucrose peanut line "JM135" was utilized to map QTLs associated with sucrose content via BSA resequencing.The results showed that the kernel sucrose content in the F₂ population ranged from 2.89% to 8.54%, exhibiting continuous variation and a normal distribution. Through BSA-seq analysis, six candidate intervals were initially identified, on chromosomes Arahy.04 and Arahy.16. Two KASP markers, 16-1475 and 16-1522, were developed for marker-assisted selection (MAS) of the kernel sucrose content in peanut. Based on gene annotation information, two candidate genes were screened. Expression profile indicated that Arahy.RUR3FB and Arahy.LJ1TN7 are potential candidate genes regulating sucrose content in peanuts. This study provides theoretical support for mining genes related to sucrose content in peanuts and offers technical support for breeding new high sugar peanut varieties through molecular breeding approaches.

Cassava MeGRXC3 mediates specific regulation of MeCAT1 enzyme activity via its key functional sites

Wang Rui-Xia, Yu Xiao-Ling, Li Shu-Xia, Zhang Xiu-Chun, Guo Xin, Gan Ping, Ruan Meng-Bin

Acta Agronomica Sinica. 2026, 52(9):  2608-2617.  doi:10.3724/SP.J.1006.2026.64003

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Glutaredoxins play a critical role in plant stress responses by modulating the redox state of cysteine residues in target proteins. Previous studies have shown that the cassava CC-type glutaredoxin MeGRXC3 interacts with catalase MeCAT1 and negatively regulates its enzyme activity, yet the underlying molecular mechanism remains unclear. To elucidate the regulatory effects of key functional sites of MeGRXC3 on MeCAT1 enzyme activity, this study constructed expression vectors carrying mutations in active domain (C21AC24A) and glutathione-binding domain (G75L) of MeGRXC3. Subcellular localization analysis indicated that mutations in these functional domains did not alter the intracellular localization of MeGRXC3. Yeast two-hybrid, bimolecular fluorescence complementation, and pull-down assays confirmed that MeGRXC3 interacts with MeCAT1 both in vivo and in vitro, and this interaction is independent of the aforementioned functional domains. However, transient expression in tobacco and biochemical analysis revealed that the negative regulation of MeCAT1 enzyme activity by MeGRXC3 is closely related to these two functional domains: mutation of the active domain attenuated the inhibitory effect, while mutation of the glutathione-binding domain completely abolished the inhibition, leading to a significant enhancement of MeCAT1 enzyme activity. These results demonstrate that the catalytic active domain and the predicted glutathione-binding domain of MeGRXC3, while dispensable for its physical interaction with MeCAT1, are essential for inhibiting MeCAT1 enzymatic activity. This indicates that MeGRXC3 likely binds to MeCAT1 through other regions/domains, subsequently depending on its conserved functional sites to execute its inhibitory role. This finding provides a crucial foundation for further elucidating the precise molecular mechanism by which MeGRXC3 regulates MeCAT1 activity at the post-translational level.

Functional characterization of SAR gene negatively regulating salt-alkaline tolerance in sorghum

Xiao Rui-Xue, Li Xiao-Peng

Acta Agronomica Sinica. 2026, 52(9):  2618-2627.  doi:10.3724/SP.J.1006.2026.64035

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Saline-alkaline land represents an important potential resource for agricultural development, and cultivating salt-alkali tolerant crops is of great significance for ensuring food security. Sorghum (Sorghum bicolor L.) possesses strong salt-alkali tolerance and as a pioneer crop on marginal lands. Through combined genome-wide association analysis (GWAS) and transcriptomic analysis, we previously identified a key major quantitative trait locus (QTL) regulating salt-alkali tolerance in sorghum, designated qSAR-1 (Salt Alkali Related), located at approximately 59.48 Mb on chromosome 1, with the candidate gene SAR (Sobic.001G309500). In this study, using sorghum inbred line Tx430, we generated T₂ stable lines with SAR overexpression and CRISPR/Cas9-mediated knockout via Agrobacterium-mediated genetic transformation. Phenotypic analysis revealed that SAR overexpression lines exhibited significant salt-alkali sensitive phenotype under salt-alkali stress, whereas knockout lines showed significantly enhanced salt-alkali tolerance with a 36% increase in survival rate. Physiological and biochemical analyses demonstrated that SAR knockout improved photosynthetic performance, reduced reactive oxygen species (ROS) accumulation and membrane lipid peroxidation, and increased antioxidant enzyme activities and osmoregulatory substance contents. Endogenous abscisic acid (ABA) measurements and inhibitor treatment experiments confirmed that SAR negatively regulates salt-alkali tolerance in sorghum primarily through the ABA pathway. This research provides valuable genetic resources and theoretical basis for molecular breeding of salt-alkali tolerant sorghum, aligning with recent breakthroughs in crop salt-alkali tolerance research.

Genetic diversity analysis and screening of elite germplasm based on phenotypic traits in 1547 broomcorn millet accessions

Wang Yue, Liu Tian-Peng, Yu Xiao-Han, Xue Ya-Peng, Yang Tian-Yu, Wang Rui-Yun, Liu Min-Xuan

Acta Agronomica Sinica. 2026, 52(9):  2628-2640.  doi:10.3724/SP.J.1006.2026.64013

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Broomcorn millet is a traditional grain crop in the Yellow River basin of northern China. In this study, 1547 broomcorn millet accessions from different ecological regions were used as experimental materials. They were planted in two experimental bases (Shunyi, Beijing and Huining, Gansu) in 2024. Genetic diversity analysis based on phenotypes was conducted using 10 agronomic traits including main stem length, main stem diameter, main stem node number, and main panicle length. Comprehensive evaluation of the accessions was performed using principal component analysis and path analysis. The results showed that the 1547 broomcorn millet accessions exhibited abundant phenotypic diversity. The genetic diversity index of the 10 agronomic traits ranging from 1.978 to 2.098, with the main stem diameter showing the highest diversity index at both experimental sites. Correlation analysis indicated varying degrees of correlations among multiple traits, with panicle weight per plant showing highly significant positive correlation with grain weight per plant. Principal component analysis extracted 4 principal components, with a cumulative contribution rate of 72.192%, representing plant type, single plant yield, grain-related traits and panicle type. Based on the combined evaluation integrating principal component analysis and breeding objectives, 23 elite broomcorn millet accessions with favorable traits such as medium to short stature, large grains, high yield, and lodging resistance were identified.

Genome-wide association and genomic selection for tassel structural traits in maize under drought stress

Zhang Wei-Wei, Ren Jiao-Jiao, Wei Lue, Wu Ruo-Tong, Tao Ting-Yu, Wu Chuan-Peng, Abulike Mu Abulimiti, Xu Xiao-Ming, Wu Peng-Hao

Acta Agronomica Sinica. 2026, 52(9):  2641-2659.  doi:10.3724/SP.J.1006.2026.63022

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Drought is a major abiotic stress that affects maize growth and development, leading to reduced yield. Tassel length (TL) and tassel primary branch number (TBN) are key structural traits influencing pollen dispersal and yield formation in maize. Elucidating the genetic basis of TL and TBN under drought stress provides theoretical support for breeding drought-tolerant and stable-yielding maize varieties. In this study, an association panel consisting of 395 maize inbred lines was subjected to multi-environment phenotyping under well-watered (WW) and drought-stressed (DS) conditions. High-density SNP markers obtained from resequencing were used to perform genome-wide association studies (GWAS) and genomic selection (GS) with the FarmCPU model. TL, TBN, and their drought resistance indices were significantly affected by environment, genotype, and genotype×environment interaction. Drought stress significantly reduced the phenotypic values of TL and TBN (P < 0.0001). Both TL and TBN exhibited high heritability under WW and DS, ranging from 72.12% to 90.19%. The heritability of the drought resistance index was 57.43% for TL and 86.22% for TBN. GWAS identified multiple SNPs significantly associated with TL, TBN, and their drought resistance indices. Specifically, 71 and 51 SNPs were associated with TL under WW and DS, respectively, while 70 and 81 SNPs were associated with TBN under WW and DS conditions, respectively. Some significant SNPs were repeatedly detected under different water regimes or in the drought resistance index analysis, indicating certain environmental stability. Among them, three co-localized SNPs were detected across WW, DS, and drought resistance index analyses, and ten co-localized SNPs were found between DS and the drought resistance index. For TBN, six co-localized SNPs were identified across WW, DS, and the drought resistance index, and thirteen co-localized SNPs between DS and the drought resistance index. These co-localized loci may be involved in the regulation of drought response in maize. GS analysis showed that when the training population proportion was 60%-70% with 20,000 markers, prediction accuracy stabilized, ranging from 0.347 to 0.483 for TL and from 0.587 to 0.609 for TBN. The prediction performance for TBN under drought stress was superior to that for TL. This study systematically elucidated the genetic characteristics of maize tassel structural traits under drought stress, providing an important theoretical basis for improving tassel architecture and drought tolerance in maize.

Maize transcription factor ZmDREB53 positively regulates plant salt tolerance by scavenging reactive oxygen species

Zhang Rui-Jia, Lyu Jian-Yu, Gao Yuan, Wang Hao-Yu, Wang Yu-Qi, Jiang Jia-Ning, Zhao Jian-Xiong, Wang Xue-He-Yuan, He Lin

Acta Agronomica Sinica. 2026, 52(9):  2660-2670.  doi:10.3724/SP.J.1006.2026.63020

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DREB transcription factors play a crucial role in plant responses to abiotic stress, but, knowledge of their functions and regulatory mechanisms in maize (Zea mays L.) under salt stress remains limited. In this study, we identified a salt-responsive gene ZmDREB53 in maize roots. Overexpression of ZmDREB53 in Arabidopsis promoted seed germination and seedling root growth under salt stress and ABA treatment. Moreover, ZmDREB53 likely enhanced the expression of stress-related genes AtMSD2 and AtPOD59 by recognizing GCC-box or CRT element, thereby increasing the activity of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione S-transferase (GST). Ultimately, this improves the salt tolerance of transgenic Arabidopsis plants. Promoter analysis revealed that the ZmMSD2 promoter had four GCC-boxes, while the ZmPOD59 promoter had two GCC-boxes and one CRT element. Dual-luciferase assays confirmed that ZmDREB53 directly bind to the promoters of ZmMSD2 and ZmPOD59 to drive their expression. In summary, this study demonstrated that ZmDREB53 regulates plant salt tolerance in Arabidopsis and preliminarily identified its target genes, providing a solid foundation for further understanding the salt tolerance mechanism of maize and for stress resistance breeding in maize.

The IM-dQTG-seq method for fine mapping of QTL at arbitrary position across the whole genome in an F₂ population

Xia Yi-Yi, Chen Ying, Wang Jing-Tian, Zhang Yuan-Ming

Acta Agronomica Sinica. 2026, 52(9):  2671-2678.  doi:10.3724/SP.J.1006.2026.62008

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In the fine mapping of QTLs, it is common to plot the marker genotypes of extreme individuals to identify recombination regions. However, this approach only provides association intervals without pinpointing recombination sites, and the plotting process is also cumbersome. To address this, we proposed the IM-dQTG-seq method for QTL fine mapping, which integrates the G_w statistic from the bulked segregant analysis (BSA)-based dQTL-seq method, extreme individual marker genotype information, and QTL conditional probability. In Monte Carlo simulation studies, the IM-dQTG-seq method achieved an average power of 79% for fine mapping of extremely over-dominant QTLs, significantly higher than other (BSA) methods, the false positive rate of the IM-dQTG-seq method was slightly lower than that of other methods. Reanalysis of 20 published QTL fine mapping studies using the IM-dQTG-seq method yielded results consistent with the original reports. In reanalysis of the dataset from Liu, et al. (2022), two QTLs were identified: one QTL consistent with the original study, was located at 81.35 cM in the interval from RM5808 to RM23205, only 7 kb away from the heat-tolerance-related gene Os08g0438400; the other novel QTL was near marker RM80, only 28 kb away from the heat-tolerance-related gene Os08g0537800. The developed software package is freely available on GitHub (https://github.com/YuanmingZhang65/dQTG.seq). Therefore, the IM-dQTG-seq method can detect QTLs at any positions across the whole genome, accurately identify recombination sites, simplify the fine-mapping process, and hold significant application value for BSA and QTL fine-mapping.

Identification, evaluation and genetic diversity analysis of Chongqing Hawk tea germplasm resource

Li Jie, Zhai Xiu-Ming, Liu Jian, Xiao Fu-Liang, Zhang Wei, Zhang Jing-Yue, Yuan Lin-Ying, Hou Yu-Jia

Acta Agronomica Sinica. 2026, 52(9):  2679-2690.  doi:10.3724/SP.J.1006.2026.64011

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The germplasm resources of Hawk tea (Litsea coreana var. Lanuginosa) are abundant in Chongqing. To explore the phenotypic characteristics, population genetic structure, and phylogenetic relationships of Hawk tea resources in this region, 110 accessions from different regions were studied using field investigation, high-performance liquid chromatography (HPLC), and genotyping by sequencing (GBS) techniques. The morphological traits, biochemical components related to quality and genetic diversity of Chongqing Hawk tea were identified and analyzed. The results showed that Chongqing Hawk tea is primarily characterized by arbor type, upright tree posture, medium to large leaves, elliptical leaf shape, acuminate leaf apex, medium to hard leaf texture, green leaf color, and dense pubescence on new shoots. The variation coefficient (CV) of new shoot color was relatively high (37.28%). The quality-related biochemical components were rich in polyphenols and flavonoids, with high diversity indices of 2.07 and 2.05, respectively. Significant differences in phenotypic and biochemical traits were observed among populations from different regions. Due to their phenol-to-ammonia ratios, the Liangping and Wuxi populations were suitable for green tea and black tea processing, respectively, providing practical guidance for the targeted utilization of germplasm resources. The results of cluster analysis, population structure analysis, and principal component analysis (PCA) were consistent, collectively dividing the 110 Hawk tea germplasm into three groups, and the grouping showed a weak correlation with their geographical distribution. The genetic differentiation coefficient (Fst) among Hawk tea populations was 0.058, indicating a moderately low level of genetic differentiation. Gene flow was the main driver of genetic differentiation among populations. Meanwhile, the Wuxi and Wulong populations exhibited a certain degree of genetic differentiation from other regional populations, suggesting that long-term artificial selection and geographic isolation are key factors shaping genetic differentiation and the formation of specific gene pools of Hawk tea resources. These findings provide critical reference for formulating conservation strategies and conducting targeted breeding of Hawk tea.

TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY

Characteristics of maize population structure and water-fertilizer use efficiency in green high-yield record fields in China

Wang En-Ci, Song Li, Zhang Deng-Long, Zhang Long, Deng Qiao-Zhen, Guo Xiao-Xia, Liu Guang-Zhou, Yang Yun-Shan, Hu Dan, Wang Fu-Lu, Chen He-Xin, Zhang Wei, Liu Dun-Yi, Liu Bin, Li Yong, Liu Wan-Mao, Ming Bo, Chen Xin-Ping, Li Shao-Kun, Zhang Fu-Suo, Hou Peng

Acta Agronomica Sinica. 2026, 52(9):  2691-2699.  doi:10.3724/SP.J.1006.2026.63039

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To fully exploit the abundant solar radiation resources of the plateau region and achieve new breakthroughs in maize yield per unit area in China, the Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, and Xizang Agriculture and Animal Husbandry University jointly conducted a high-yield maize demonstration in Nyingchi, Xizang, in 2025 at an altitude of 2942 m. Through the integrated application of cultivation technologies, including moderate planting density, promotion of double-ear formation, precise water and fertilizer management, and green production, the demonstration field achieved a yield of 27.64 t hm^-2, breaking the national maize yield record previously set by the same team in 2024. The cultivar Xianyu 1483 was used in both record-setting years, with planting densities of 75,000 and 82,500 plants hm^-2, respectively. Comparative analysis of the characteristics of high-yield maize populations and water-fertilizer use over the two years showed that, in 2025, the population had a double-ear rate of 72%, a harvest ear number of 141,895 ears hm^-2, 546 kernels per ear, a 1000-kernel weight of 441.64 g, and a grain weight per ear of 201.79 g. Compared with 2024, as planting density increased, the double-ear rate decreased significantly by 16.09%, whereas kernel number per ear, grain weight per ear, and 1000-kernel weight increased significantly by 12.48%, 18.70%, and 14.16%, respectively. In 2025, aboveground dry matter accumulation reached 49.41 t hm^-2, with a harvest index of 0.61. Dry matter accumulation before and after flowering was 13.44 t hm^-2 and 35.97 t hm^-2, respectively, representing significant increases of 21.41% and 19.38% (P < 0.05) compared with 2024. Post-flowering dry matter accumulation accounted for 72.80% of total dry matter, which was generally consistent with that in 2024. Logistic equation fitting showed that, compared with 2024, the time to reach the maximum dry matter accumulation rate (T_max) occurred 6.55 days earlier in 2025 than in 2024. The dry matter accumulation at the maximum accumulation rate (W_max), maximum dry matter accumulation rate (R_max) and mean dry matter accumulation rate (R_mean) increased by 9.66%, 19.87%, and 17.72%, respectively, and the active duration of dry matter accumulation (P) was shortened by 14.20 days. In 2025, the partial factor productivity of nitrogen, phosphorus, and potassium fertilizers was 53.12, 163.83, and 180.52 kg kg^-1, respectively, and irrigation water use efficiency reached 15.06 kg m^-3. In 2024, the corresponding partial factor productivity values for nitrogen, phosphorus, and potassium fertilizers were 48.07, 144.21, and 464.68 kg kg^-1, respectively, and irrigation water use efficiency was 11.48 kg m^-3. High water-fertilizer use efficiency was achieved in both years. These findings provide a new technical pathway for green, high-yield maize production and offer important reference value for achieving the goal of 1.5 t grain per mu in green maize production in Xizang and across China.

Photosynthetic-physiological mechanisms of N fertilizer postponing application on yield improvement of maize in the wheat-maize intercropping system

Cui Wen-Jie, Yan Zhe-Lin, Ren Qiang, Fan Zhi-Long, Yin Wen, Sun Ya-Li, Fan Hong, He Wei, Wang Feng, Hu Fa-Long, Chai Qiang

Acta Agronomica Sinica. 2026, 52(9):  2700-2712.  doi:10.3724/SP.J.1006.2026.53101

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Aiming at the problems of unreasonable application of nitrogen fertilizer and unclear yield formation mechanism in the wheat-maize intercropping system in oasis irrigation area, this study focused on intercropped maize. Different cropping patterns and nitrogen application systems were established to reveal the photosynthetic physiological mechanisms underlying yield improvement in wheat-maize intercropping under delayed nitrogen application. The experiment was conducted during 2023-2024 at the Wuwei Oasis Agricultural Comprehensive Experimental Station of Gansu Agricultural University using a randomized complete block design. Two factors were examined: planting pattern (sole maize, SM; wheat-maize intercropping, IM) and nitrogen application regime (conventional nitrogen application, N1; 10% delayed nitrogen application, N2; 20% postponed nitrogen application, N3), resulting in six treatments. The results showed that the IM pattern exhibited superior photosynthetic characteristics during the late growth stage compared to SM. Compared with SM, IM exhibited higher net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) and lower intercellular CO₂ concentration (C_i), and postponed nitrogen fertilizer application further optimized the photosynthetic characteristics of the IM pattern. During the mid to late growth stage (silking to mid-grain filling), P_n, G_s, T_r, SPAD, and LAI of IM were on average 20.5%, 22.5%, 23.0%, 15.5%, and 10.6% higher than those of SM, respectively. Under the two planting patterns, the P_n, G_s, T_r, SPAD, and LAI of the N3 treatment were increased by 11.8%, 10.9%, 12.4%, 9.0%, and 7.9%, respectively, compared with N1 during the mid to late growth stage. The P_n, G_s, SPAD, and LAI of IMN3 during the mid to late growth stage were on average 11.6%, 12.8%, 7.8%, and 10.4% higher than those of IMN1, respectively, while the G_s of IMN3 was increased by 12.1% on average from silking to early grain filling compared with IMN1. In addition, the LAD of IM at the R1-R2 and R2-R3 stages was 11.2% and 12.6% higher than that of SM, respectively; the LAD of the N3 treatment was 6.9% and 8.2% higher than that of N1, respectively; and the LAD of IMN3 was 7.3% and 8.7% higher than that of IMN1, respectively. Over the two years, the grain yield of IMN3 was increased by an average of 23.7% and 65.9% compared with IMN1 and SMN1, respectively, and the light use efficiency (LUE) of IMN3 was increased by 12.8% and 31.9% compared with IMN1 and SMN1, respectively. Random Forest analysis showed that before wheat harvest, G_s, LAD and P_n were the main influencing factors on maize yield, while after wheat harvest, P_n, C_i, LAD, G_s, T_r, and SPAD were the main influencing factors. Therefore, IM combined with 20% nitrogen fertilizer postponing can enhance photosynthetic physiological indicators such as net photosynthetic rate, stomatal conductance, and relative chlorophyll content, improve light use efficiency and maize yield, thereby achieving high yield and high efficiency in this pattern.

Effects of integrating liquid film mulching with micro-ridge-furrow planting on light energy utilization and yield improvement of summer maize in arid areas

Wang Jia-Hao, Wang Xiao-Ling, Fan Zhen, Guo Guang-Xu, Feng Wen-Jing, Zhang Xin-Bo, Luo Xuan, Ren Xiao-Long, Chen Xiao-Li

Acta Agronomica Sinica. 2026, 52(9):  2713-2724.  doi:10.3724/SP.J.1006.2026.63009

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Integrating liquid film mulching with micro-ridge-furrow planting is an effective cultivation practice for drought resistance and yield maintenance, and can help alleviate the severe constraints imposed by drought on maize yield improvement in the Guanzhong Plain of China. However, the specific effects of this integrated technology on canopy light utilization and yield formation in summer maize under dryland conditions remain unclear, and the responses of maize growth and yield to different ridge-furrow ratios in the Guanzhong Plain have not yet been fully determined. In this study, a two-year field experiment was conducted with seven treatments, including three ridge-furrow ratios and two mulching methods, with traditional flat planting used as the control. The objectives were to clarify the yield-increasing mechanism of liquid film-mulched ridge-furrow planting in dryland maize and to determine the optimal ridge-furrow ratio for the Guanzhong Plain, thereby providing new insights into dryland agricultural development in this region and beyond. The results showed that, compared with traditional flat planting, liquid film-mulched ridge-furrow treatments increased soil temperature (ST) and soil water content (SWC) by averages of 8.76% and 11.22%, respectively, and enhanced stomatal conductance (G_s), photosynthetic rate (P_n), relative chlorophyll content (SPAD), and leaf area index (LAI) by averages of 26.03%, 30.37%, 6.79%, and 20.02%, respectively, resulting in an average yield increase of 16.12%. These findings indicate that liquid film-mulched ridge-furrow treatments increase LAI, SPAD, and G_s by improving ST and SWC, thereby enhancing the photosynthetic rate of maize leaves. In addition, increases in ST and SWC can directly promote photosynthesis, ultimately contributing to higher summer maize yield. Furthermore, the results showed that, in dry years in the Guanzhong Plain, a ridge-furrow ratio of 40:40 combined with liquid film mulching was more effective in increasing yield, whereas in wet years, a ridge-furrow ratio of 40:60 combined with liquid film mulching produced a more pronounced yield-increasing effect.

Screening and characterization of high-yielding rice varieties for noodle processing in Jiangxi province, China

Liao Ping, Du Han-Meng, Jiang Xin-Tong, Dou Zhi, Gao Hui, Huang Min, Huang Shan, Zeng Yong-Jun, Zhang Hong-Cheng

Acta Agronomica Sinica. 2026, 52(9):  2725-2743.  doi:10.3724/SP.J.1006.2026.62012

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Screening high-yielding rice varieties suitable for rice noodle production and elucidating their agronomic traits, cooking quality, and eating quality are of great significance for promoting the high-quality development of the early rice industry in Jiangxi province, China. From 2024 to 2025, a field experiment was conducted in Shanggao county, Jiangxi province, to screen high-yielding rice varieties suitable for rice noodle production. A comprehensive analysis of growth duration, grain yield, cooking quality, eating quality, starch components, protein content, and rapid visco analyzer (RVA) profile characteristics was performed by integrating analysis of variance, subgroup analysis, correlation analysis, and random forest modeling. The results showed that the high-yielding varieties included Anyou 5020, Lingliangyou 211, Lingliangyou 737, Zhuliangyou 819, Songyazao 1, Xiangzaoxian 45, Zhongjiazao 17, Zhongjiazao 52, Zhongzao 35, and Zhongzao 39. Varieties with superior cooking and eating quality included Zhongjiazao 17, Zhongjiazao 52, Zhongzao 35, and Zhongzao 77. Considering high yield, good cooking quality, and desirable eating quality, Zhongjiazao 17, Zhongjiazao 52, and Zhongzao 35 were recommended as high-yielding rice varieties suitable for noodle processing and cultivation in Jiangxi province. These three varieties had growth durations of 114-117 days and grain yields of 7698-9565 kg hm^-2. In terms of rice noodle quality, cooked breakage rate, cooking loss rate, and water absorption rate ranged from 0 to 3.44%, 2.10% to 8.40%, and 51.47% to 78.46%, respectively. Hardness, chewiness, and springiness ranged from 1100 to 1462 g, 809 to 1080 g, and 90.15% to 91.81%, respectively. Total starch and amylose contents ranged from 70.91% to 77.44% and from 24.05% to 29.23%, respectively. Correlation analysis showed that total starch and amylose contents were negatively correlated with cooked breakage rate and cooking loss rate but positively correlated with water absorption rate and eating quality. Both total starch and amylose made significant contributions to cooking and eating quality. Trough viscosity was negatively correlated with cooked breakage rate and cooking loss rate but positively correlated with water absorption rate, springiness, and cohesiveness. In addition, trough viscosity ranked first in its contribution to cooking loss rate, water absorption rate, springiness, and cohesiveness. In conclusion, total starch content, amylose content, and trough viscosity can be used as key indicators for evaluating the cooking and eating quality of rice varieties for noodle processing.

Study on the regulatory mechanism of carbon-nitrogen metabolism and yield-increasing effects of exogenous sodium nitroprusside spraying on rice in saline-alkaline soil

Tang Hai-Jiang, Guo Fu-Cheng, Xiao Dong-Hao, Yang Jiu-Ju, Su Jing, Liao Ting-Lu, Wang Yan-Qi, Luo Cheng-Ke

Acta Agronomica Sinica. 2026, 52(9):  2744-2759.  doi:10.3724/SP.J.1006.2026.62007

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To clarify the regulatory effects of foliar spraying of sodium nitroprusside (a nitric oxide donor, SNP) on carbon and nitrogen metabolism and yield of rice in saline-alkaline soil, a two-year field experiment was conducted using the rice variety Ningjing 75. Three different concentrations of SNP (50 μmol L^-1, X1; 100 μmol L^-1, X2; and 150 μmol L^-1, X3) were sprayed on the leaves during the seedling to tillering stages, with distilled water as the control (CK). The effects of SNP spraying on indicators related to carbon and nitrogen metabolism and yield were systematically analyzed. The results indicated that, compared with control (CK), the net photosynthetic rate (P_n), stomatal conductance (G_s), intercellular CO₂ concentration (C_i), and transpiration rate (T_r) of rice under 50-100 μmol L^-1 SNP treatment increased by 9.23%-18.87%, 15.58%-18.41%, 7.48%-9.50%, and 9.77%-20.14%, respectively, averaged over two years. The maximum photochemical efficiency of PSII (F_v/F_m), potential maximum photosynthetic efficiency of PS (F_v/F_o), and photochemical quenching coefficient (q_P) increased, by 5.27%-7.95%, 12.78%-24.44%, and 5.78%-7.07%, respectively, while the non-photochemical quenching coefficient (NPQ) decreased by 6.33%-6.71%. The activities of key carbon-metabolism enzymes including sucrose synthase (SS), sucrose phosphate synthase (SPS), and phosphoenolpyruvate carboxylase (PEPC) were enhanced by 6.52%-11.25%, 10.30%-13.95%, and 14.06%-16.43%, respectively. The activities of key nitrogen-metabolism enzymes including nitrate reductase (NR), glutamine synthetase (GS), and glutamate synthase (GOGAT) increased by 17.99%-23.69%, 12.96%-24.23%, and 13.61%-20.20%, respectively. The improvements in photosynthetic characteristics and the activities of carbon- and nitrogen-metabolism enzymes significantly promoted dry matter accumulation and yield increase, with average increased of 6.99%-10.72% and 4.46%-6.85%, respectively. Further analysis using a partial least squares path model (PLS-PM) revealed that SNP spraying preferentially enhanced, the nitrogen metabolism enzyme activities, which indirectly influenced carbon metabolism enzyme activities and photosynthetic rate, thereby promoting dry matter accumulation and yield increase. In conclusion, spraying appropriate concentration (50-100 μmol L^-1) can effectively improve photosynthetic performance, enhance the activities of key carbon and nitrogen metabolism, and consequently increase rice yield in saline-alkaline soil.

Alleviating effect of a compound agent of potassium polyaspartate and betaine on assimilate accumulation, translocation and yield of wheat under high temperature stress during grain-filling stage

Yang Lu-Yao, Cui Ru-Ying, Dong Xue-Rui, Yan Peng, Zhang Juan, Zhang Cai-Xia, Wang Yong-Jun, Dong Zhi-Qiang, Lu Lin

Acta Agronomica Sinica. 2026, 52(9):  2760-2774.  doi:10.3724/SP.J.1006.2026.61016

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To study the effects of and physiological mechanisms of a potassium polyaspartate and betaine compound agent (total active ingredient content 35%, hereinafter referred to as “PG”) on assimilate accumulation, translocation and yield of wheat under high-temperature stress during grain filling, field experiments were carried out at the Xinxiang Experimental Base of Chinese Academy of Agricultural Sciences from 2022 to 2024. Two wheat cultivars, Zhongmai 578 (ZM578) and Xinmai 26 (XM26), were used as test materials. A randomized block design was adopted, with chemical regulation and high temperature treatment. The chemical regulation treatment involved foliar spraying of PG at the flag leaf stage, while the high-temperature treatments were applied at early grain filling stage (EH) and mid-grain filling (MH). Ambient temperature with water spray served as the control (CK). The results showed that under high-temperature stress, the accumulation of assimilate in the rachis and glumes significantly increased in both cultivars, while accumulation in leaves and grains significantly decreased; no significant difference was observed in assimilate accumulation in stems and sheaths. Compared with CK, high temperature stress significantly increased the pre-anthesis assimilate translocation amount, translocation efficiency, and contribution to grains, whereas post-anthesis assimilates accumulation amount, accumulation rate, translocation amount and contribution to grains were significantly decreased, ultimately leading to a significant decrease in total assimilate accumulation at maturity, grain weight per spike, and harvest index. Under PG application followed by high-temperature stress, the total assimilates accumulation at maturity stage, post-anthesis assimilate accumulation amount and accumulation rate and the proportion of assimilates allocated to grains significantly increased in both cultivars. The flag leaf SPAD value, sucrose synthase activity in the synthesis direction (SS-II), and grain sucrose synthase activity in the degrading direction (SS-I) increased; flag leaf sucrose content increased, while grain sucrose content decreased. Compared with EH and MH alone, PG-EH and PG-MH treatments increased the yield of ZM578 by 18.85% and 5.85% in 2023, and that of XM26 by 18.76% and 9.72%, respectively. In 2024, yield increases for ZM578 were 7.99% and 5.11%, and for XM26 were 19.71% and 10.39% respectively. In summary, foliar application of the potassium polyaspartate and betaine compound agent can significantly delay flag leaf senescence, maintain sucrose metabolic balance, enhance assimilate synthesis and translocation to grains, increase assimilate accumulation and distribution ratio of in grains, and reduce grain yield loss under high-temperature stress. This approach can serve as an important cultivation technique for heat resistance and yield increase in the Huang-Huai wheat area.

Effects of intercropping green manure on spring maize grain yield and farmland soil quality in Northeast China

Li Zong, Ye Rong-Qi, Sun Hui-Jun, Guo Wei-Hong, Luo Zi-Heng, Liu Shuo, Ren Yong-Feng, Zhang Wen, Gong Xiang-Wei, Jiang Ying

Acta Agronomica Sinica. 2026, 52(9):  2775-2791.  doi:10.3724/SP.J.1006.2026.63023

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To explore the effects of spring maize intercropping with green manure crops on soil quality and crop productivity in the cinnamon soil region of Northeast China, a field experiment was conducted at the Fuxin National Agricultural Environment Observation and Experimental Station in Fumeng County, Liaoning Province, China, from 2024 to 2025. Five cropping systems were established: traditional maize monoculture (CK), maize monoculture (MC), maize-alfalfa intercropping (MA), maize-hairy vetch intercropping (MH), and maize-common vetch intercropping (MP). Dynamic changes in soil physicochemical properties, microbial biomass carbon, microbial biomass nitrogen, and enzyme activities were systematically monitored in the 0-20 and 20-40 cm soil layers. The results showed that soil bulk density (BD) and pH under the MP treatment were 6.35% and 0.58% lower than those under CK, respectively. The mean weight diameter (MWD) and geometric mean diameter (GMD) of soil aggregates under the MA treatment were 10.53%-194.17% higher than those under CK in the 0-20 and 20-40 cm soil layers. Compared with CK, the contents of soil organic carbon (SOC), total nitrogen (TN), nitrate nitrogen (NO3^--N), available phosphorus (AP), and available potassium (AK) under the MA treatment increased by 7.69%-207.76%, with the greatest increase observed for AP. In addition, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) under the MA treatment increased by 21.93% and 93.72%, respectively, on average compared with CK. Soil β-glucosidase (BG), cellobiohydrolase (CBH), β-xylosidase (BX), leucine aminopeptidase (LAP), and alkaline phosphatase (ALP) activities increased by 18.88%-108.03% compared with CK. The soil quality index (SQI) under the MA treatment increased by 16.96% and 26.87% in the 0-20 and 20-40 cm soil layers, respectively, while maize grain yield increased by 15.16% on average compared with CK. Mantel test analysis showed that SQI and maize grain yield were significantly and positively correlated with pH, MWD, TN, available nutrients, and enzyme activities. Random forest analysis further indicated that pH, BD, SOC, TN, AK, MBC, BG, and other indicators were key factors affecting maize yield. Overall, intercropping maize with green manure crops in the cinnamon soil region of Northeast China can synergistically improve soil quality and maize yield, with maize-alfalfa intercropping showing the best performance. This system therefore has potential application value for integrating land use with soil fertility improvement.

Regulation by zinc citrate of crop salt tolerance and soil electrical conductivity

Zhao Hai-Yang, Guo Xu-Peng, Luo Yang, Yang Gang, Cai Zhen-Liang, Hu Zan-Min, Chen Yu-Hong, Fan Cheng-Ming, Zhang Xin-Yong

Acta Agronomica Sinica. 2026, 52(9):  2792-2808.  doi:10.3724/SP.J.1006.2026.64027

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Soil salinization significantly inhibits crop seed germination and seedling growth, and zinc fertilizer is often poorly utilized in saline-alkali soils. Therefore, exploring the alleviating effects of zinc citrate (ZnCit) on different crop species under salt stress and its regulatory effects on soil salinity is important for the sustainable improvement of saline-alkali land. In this study, rapeseed (Brassica napus) was used as the target crop, and maize (Zea mays), wheat (Triticum aestivum), and sorghum (Sorghum bicolor) were used for phenotypic validation. Paper-based germination, pot, and soil column simulation experiments were conducted to investigate the regulatory effects of ZnCit on crop germination, seedling growth, and soil electrical conductivity (EC) under salt stress. The results showed that 100 mg L^-1 ZnCit was the optimal concentration, significantly increasing germination rate, biomass accumulation, and root growth in all four crops under salt stress. The most pronounced alleviating effect was observed in rapeseed, in which the germination rate increased by 171.5% compared with the salt-stress control. Meanwhile, 100 mg L^-1 ZnCit reduced the EC value of the 0-5 cm topsoil layer in saline-alkali soil by 74.1%. Further physiological analysis showed that ZnCit significantly reduced the Na⁺/K⁺ in rapeseed roots, optimized Zn ion distribution, and maintained ion homeostasis. ZnCit also inhibited the excessive accumulation of H₂O₂ and O₂^? induced by salt stress, enhanced the activities of SOD, POD, and CAT, reduced MDA content, and alleviated membrane lipid peroxidation damage in rapeseed. In conclusion, ZnCit achieved the dual effects of soil desalination and enhanced salt tolerance in rapeseed through the synergistic mechanisms of rhizosphere chemical amelioration and plant physiological activation, providing a new strategy for the improvement of saline-alkali soils.

RESEARCH NOTES

Construction of a Fourier transform near-infrared (FT-NIR) prediction model for oil content in single soybean seeds

Yu Lin-Feng, Li Jing, Zhang Sheng-Rui, Ma Cai-You, Hao Zhao-Yi, Li Bin, Sun Jun-Ming

Acta Agronomica Sinica. 2026, 52(9):  2809-2821.  doi:10.3724/SP.J.1006.2026.65019

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In soybean breeding, non-destructive determination of oil content in single-seeds is of great significance for early-generation screening and individual selection. However, single-seed near-infrared (NIR) spectra are susceptible to factors such as enhanced light scattering effects, reduced signal-to-noise ratio, and reference value errors, and the modeling stability of this approach remains systematically unassessed. In this study, 89 soybean varieties with wide range of oil content variation were selected from 1600 soybean germplasm accessions, and 124 single seeds were used as experimental samples. The oil content of each single seed was determined using a modified Soxhlet extraction method (range: 14.41%-25.46%), and single-seed Fouriert-transform near-infrared (FT-NIR) reflectance spectra were collected. The effects of different spectral preprocessing methods, modeling algorithms, and feature variable selection strategies, on the performance of oil prediction models were systematically evaluated. The results showed that under the preprocessing of standard normal variate combined with first derivative (SNV+D1), the partial least squares (PLS) model achieved the best performance with an independent test set R² of 0.81 and RMSE of 0.0095, outperforming rrBLUP, random forest (RF), k-nearest neighbors (KNN), and XGBoost. Variable compression results indicated that when the number of spectral variables was reduced to 27% of the original wavebands, the model R² remained at approximately 0.59, retaining about 72% of the explanatory power, suggesting that oil-related spectral information is dispersedly distributed across the NIR region. Further comparison showed that variable subsets selected by VIP (variable importance in projection) slightly outperformed those selected by literature-based waveband strategies in predictive performance. In summary, latent-variable-based linear modeling methods exhibit higher stability and applicability for single-seed NIR-based oil prediction, and moderate spectral variable compression holds potential engineering application value while preserving predictive ability. This study provides a methodological reference for the large-scale application of single-seed NIR technology in soybean breeding.

Accurate estimation of lysine content in waxy maize based on near-infrared spectroscopy and genomic information

Zhang Shu-Yu, Ma Lu, Ma Liang, Zhu Hong, Zhang Hui-Min, Song Xu-Dong, Zhou Guang-Fei, Mao Yu-Xiang, Lu Hu-Hua, Chen Guo-Qing, Hao De-Rong, Zhang Zhen-Liang

Acta Agronomica Sinica. 2026, 52(9):  2822-2838.  doi:10.3724/SP.J.1006.2026.63006

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Lysine is one of the essential amino acid human life activities, closely associated with protein synthesis and promoting growth and development. Developing a near-infrared spectroscopy prediction model for lysine content in waxy maize is of great significancy for mining germplasm resources with elevated lysine content. In this study, 145 waxy corn samples with rich genetic variation were selected, and a partial least squares (PLS) method in Unscrambler X 10.4 software was used to construct a NIRS prediction model for lysine content in waxy maize. The model achieved a cross-validation coefficient of determination (R²) of 0.895 and a root mean square error of cross-validation (RMSECV) of 0.022. External validation under different environmental conditions, yielded correlation coefficients (r) of 0.901 and 0.907, demonstrating strong practical utility of the model. Using this model, lysine content was measured in 186 waxy maize inbred lines and 341 hybrids derived from them. The results showed that the phenotypic variation ranged of the inbred lines was 0.20-0.40 g 100g^-1, with a coefficient of variation of 10.35%. No significant differences in lysine content were observed among different heterotic groups. For hybrids, lysine content ranged from 0.16 to 0.56 g 100g^-1, with a coefficient of variation of 21.79%. The heterotic patterns, Pop2 × Pop4 and Pop1 × Pop4, were identified as optimal for lysine content in waxy maize hybrids. Using the lysine content data of 341 waxy maize hybrids as a training population, general combining ability (GCA) of the 186 inbred lines was accurately estimated via linear mixed model based on genomic information. Three genomic selection (GS) methods: BayesB, GBLUP and LASSO—were then used to predict lysine content for all possible hybrid combinations (186×185×0.5 = 17,205 hybrids) derived from the 186 inbred lines. The top 50 hybrids with the highest predicted lysine content (Top50) and the bottom 50 with the lowest (Bottom50) were selected for field validation. The results showed that the lysine content in the Top50 hybrids, as validated by BayesB, GBLUP and LASSO, was 31.3%, 22.0% and 27.7% higher than that of the control variety (Suyunuo 5), respectively; 28.8%, 22.8%, and 22.5% higher than the overall mean of all validated hybrids, respectively; and 77.5%, 54.5% and 63.5% higher than the mean of the Bottom50 validated hybrids, respectively. GCA analysis revealed that the parental inbred lines of Top50 hybrids exhibited higher GCA for lysine content, while those of Bottom50 hybrids showed lower GCA. Therefore, developing waxy maize hybrids with high lysine content, first requires breeding parental inbred lines with high GCA for lysine content. This study effectively integrates near-infrared spectroscopy technology and genomic selection, providing a novel approach for the accurate estimation of lysine content and precise breeding for quality traits in waxy maize.