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Identification of upstream regulators for mitogen-activated protein kinase 7 gene ( BnMAPK7) in rapeseed ( Brassica napus L.) WANG Zhen, ZHANG Xiao-Li, MENG Xiao-Jing, YAO Meng-Nan, MIU Wen-Jie, YUAN Da-Shuang, ZHU Dong-Ming, QU Cun-Min, LU Kun, LI Jia-Na, LIANG Ying Acta Agronomica Sinica    2021, 47 (12): 2379-2393.   DOI: 10.3724/SP.J.1006.2021.04280 Abstract （353）   HTML （173）    PDF（pc） （12120KB）（658）       Knowledge map    Save Mitogen-activated protein kinases (MAPKs) cascade plays a key role in plant growth and development, division, differentiation, apoptosis, and stress resistance. In this study, a 1612 bp promoter of C group BnMAPK7 gene, designated ProBnMAPK7, was cloned from Brassica napus. Promoter structure prediction by PlantCARE revealed that ProBnMAPK7 contained a lot of ACE, MRE, ABRE, TGACG-motif, and TC-rich repeats cis-acting elements, which involved in light, hormones, defense, and wounding responsiveness. At the same time, we analyzed the expression patterns of MAPK7 genes in Arabidopsis and B. napus, and found that MAPK7 played an important regulatory role in growth and development process and responding to biotic and abiotic stresses. Different lengths of ProBnMAPK7 were gradually ligated to the pCambia1305.1-GUS expression vector to identify the core fragment. GUS histochemical staining analysis showed that the core fragment of ProBnMAPK7 was located in the -467 to -239 bp (ProBnMAPK7-rPE) region. Three copies of the promoter core fragment were integrated into the genome of Y1H gold to test the AbA background. The data demonstrated that the expression background of ProBnMAPK7-rPE in yeast cells was completely inhibited by 500 ng mL-1 AbA. Using yeast one-hybrid, we screened the library of the upstream regulatory factors of BnMAPK7, and obtained three candidates, including BnNAD1B (NADH dehydrogenase 1B), BnERD6 (early response to dehydration 6), and BnPIG3 (quinone oxidoreductase PIG3-like). Taken together, these results suggested that BnNAD1B, BnERD6, and BnPIG3 might bind to ProBnMAPK7-rPE to regulate the transcription of BnMAPK7, to further involve in photosynthesis and responding to stresses. This study lays a foundation for further elucidating the function of BnMAPK7 in rapeseed, and provides a new perspective for research into MAPKs cascade. Table and Figures | Reference | Related Articles | Metrics

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Research progress on traits and assessment methods of stalk lodging resistance in maize ZHAO Xue, ZHOU Shun-Li Acta Agronomica Sinica    2022, 48 (1): 15-26.   DOI: 10.3724/SP.J.1006.2022.03055 Abstract （422）   HTML （46）    PDF（pc） （959KB）（604）       Knowledge map    Save Maize stalk lodging causes yield loss, decreases grain quality, increases harvest costs, and makes it impossible for grain dehydration after physiological maturity which limits mechanical grain harvest. Previous researches have been conducted to study the traits related to stalk lodging, including morphological and anatomical traits, chemical constituents of the plant and internode. However, there exist some disagreements, and lack quantitative studies on stalk lodging resistance. In this study, we review the evaluation methods and indicators of stalk lodging resistance, the determination methods of mechanical properties as well as analysis methods of stalk lodging related traits and some factors that may have effects on the results. Furthermore, we put forward the existing problems in previous researches on traits and evaluation indicators related to stalk lodging resistance and the contents need to be given further attention. These results provide a reference for further study of maize stalk lodging resistance traits and evaluation methods, lodging resistance breeding and optimization of cultivation measures. Table and Figures | Reference | Related Articles | Metrics

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Dissecting the genetic architecture of maize kernel size based on genome-wide association study QU Jian-Zhou, FENG Wen-Hao, ZHANG Xing-Hua, XU Shu-Tu, XUE Ji-Quan Acta Agronomica Sinica    2022, 48 (2): 304-319.   DOI: 10.3724/SP.J.1006.2022.13002 Abstract （306）   HTML （34）    PDF（pc） （4960KB）（598）       Knowledge map    Save Kernel size related traits are one of the important compounds of yield, and they are also complex quantitative traits regulated by multiple genes. Mining the key regulatory genes of maize kernel size related traits will help to improve the yield. In this study, 212 excellent maize inbred lines were selected as materials. The kernel length, kernel width, and kernel thickness were measured in 2018 and 2019, respectively, and we performed genome-wide association study (GWAS) based on 73,006 single nucleotide polymorphic (SNP) markers uniformly distributed in maize genome. Based on the FarmCPU algorithm, 47 SNP markers associated with kernel size related traits were detected on 10 chromosomes in maize. Combined with the public dynamic spatio-temporal transcriptional data of kernel development of B73 maize inbred line, 58 candidate genes related to kernel size were detected in the linkage disequilibrium (LD) region marked by significant SNP. The proteins encoded by candidate genes interacted with multiple proteins and participated in and regulated many biological processes closely related to kernel development. These results provide a new reference for understanding the molecular regulation mechanism of maize kernel development, improving kernel size and increasing crop yield. Table and Figures | Reference | Related Articles | Metrics

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Research advances of cover crops and their important roles JIAN Shu-Lian, LI Shu-Xin, LIU Sheng-Qun, LI Xiang-Nan Acta Agronomica Sinica    2022, 48 (1): 1-14.   DOI: 10.3724/SP.J.1006.2022.03058 Abstract （537）   HTML （80）    PDF（pc） （1301KB）（558）       Knowledge map    Save In crop planting system, the influences of field weeds and soil properties on crop growth and development, yield, and quality have always been paid close attention to agriculture field. Overdose applications of chemical fertilizers and herbicides are beneficial for crop yield and well control of weeds, however, their negative impacts on soil and environment seriously restrict the sustainable development of agricultural production. Planting cover crops have been considered as a novel strategy to achieve sustainable agricultural development, which can help to control weeds, reduce nitrogen application, and improve soil quality. We summarize the current research advance progress of cover crops and their application in crop cultivation, including the origin and development process, main types, functions, and cropping systems of cover crops, in order to provide a theoretical basis for the research and application of cover crops in agriculture production in China. Table and Figures | Reference | Related Articles | Metrics

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Genetic diversity analysis of Chinese fresh corn hybrids using SNP Chips XIAO Ying-Ni, YU Yong-Tao, XIE Li-Hua, QI Xi-Tao, LI Chun-Yan, WEN Tian-Xiang, LI Gao-Ke, HU Jian-Guang Acta Agronomica Sinica    2022, 48 (6): 1301-1311.   DOI: 10.3724/SP.J.1006.2022.13031 Abstract （392）   HTML （56）    PDF（pc） （5135KB）（456）       Knowledge map    Save China is a major fresh corn production and consumption country in the world. Assessment of genetic diversity and relationships among fresh corn hybrids in China has great benefit for hybrid identification and breed cultivation. In this study, an Illumina Maize 6K chip was employed to perform genome-wide scanning for the population structure and genetic distance of 385 fresh corn hybrids nationwide. The results showed that the average genetic diversity of 5067 SNP markers in 385 fresh corn hybrids was 0.406, with a range of 0.097-0.500. The average polymorphic information content (PIC) was 0.319, with a range of 0.092-0.375. The results of PCA and population genetic structure analysis revealed that the hybrids were mainly divided into three groups, which were non-sweet corn group (185 varieties), temperate sweet corn group (123 varieties), and tropical sweet corn group (77 varieties). The genetic distance between any two hybrids ranged from 0.132 to 0.472, with an average of 0.37. A total of 160 genome regions indicated strong population differentiation among different groups following FST analysis. Four key genes (sh2, su1, su2, and wx1) of starch synthesis pathway in maize grains were detected. Two candidate genes (sh2 and DGAT1-2) demonstrated different selection patterns in fresh corn groups and were validated using molecular markers. These results provide important theoretical guidance for the breeding and improvement of fresh corn varieties in China. Table and Figures | Reference | Related Articles | Metrics

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Mapping and candidate gene analysis of silique number mutant in Brassica napus L. ZHAO Gai-Hui, LI Shu-Yu, ZHAN Jie-Peng, LI Yan-Bin, SHI Jia-Qin, WANG Xin-Fa, WANG Han-Zhong Acta Agronomica Sinica    2022, 48 (1): 27-39.   DOI: 10.3724/SP.J.1006.2022.04281 Abstract （321）   HTML （28）    PDF（pc） （10417KB）（394）       Knowledge map    Save The silique number is one of the important components of yield per plant in oilseed rape (Brassica napus L.) and the exploitation and utilization of its excellent alleles are essential to increase yield. More than hundreds of silique number QTLs have been mapped in oilseed rape, but they are difficult to be fine-mapped or cloned because of their moderate and unstable effects. A oilseed rape mutant (No.7931) was detected in previous study and it had few siliques at mature stage due to the stop growth after differentiation about 10 flowers on the top of inflorescence. A F2 segregating population consisting of 3400 individuals was constructed using this mutant and another more-silique lines No.73290. Among them, we performed BSA-seq on 30 individuals with extreme more- or less-siliques and detected three associated intervals of 0-1.1 Mb, 4.7-6.2 Mb, and 11.5-12.4 Mb on the C02 chromosome. These genomic intervals contained a total of 522 annotated genes in the reference genome DarmorV8.1, among which 235 genes had functional annotation and SNP/InDel variation. At the early stage of flower bud differentiation, the shoot apical meristems of two parents were subjected to RNA-seq, and a total of 8958 differentially expressed genes (DEGs) were detected. These DEGs were significantly enriched into 20 pathways, including carbohydrate metabolism, translation, and amino acid metabolism (highly associated with flower bud differentiation) and so on, among which 99 were located in the associated intervals. By the integration of gene functional annotation as well as sequence and expression variation analysis, a total of nine candidate genes (BnaC02g00490.1D2, BnaC02g01030.1D2, BnaC02g01120.1D2, BnaC02g00270.1D2, BnaC02g02670.1D2, BnaC02g08680.1D2, BnaC02g08890.1D2, BnaC02g09480.1D2, and BnaC02g10490.1D2) were identified, which were mainly involved in the maintenance of inflorescence meristems and the regulation of flower development. The above results lay the foundation for the following fine-mapping and cloning of the silique number mutant gene in oilseed rape. Table and Figures | Reference | Related Articles | Metrics

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Contents and compositions of amino acids in rice grains and their regulation: a review YANG Jian-Chang, LI Chao-Qing, JIANG Yi Acta Agronomica Sinica    2022, 48 (5): 1037-1050.   DOI: 10.3724/SP.J.1006.2022.12062 Abstract （415）   HTML （55）    PDF（pc） （658KB）（394）       Knowledge map    Save Amino acids in cereal grains are important nutrients for both human and animals. Increasing the content of amino acids in the rice grain, especially lysine and other essential amino acids, plays a very important role in improving the nutritional standard of people in the countries with rice as staple food. This paper reviewed some research progresses in the contents and compositions of amino acids in the mature grain of rice and their distribution in the different parts of a grain, the synthesis and metabolism of amino acids in the grain, the role of plant hormones in regulating the synthesis and metabolism of on amino acids, and the effects of environmental factors and cultivation practices on the contents and compositions of amino acids in the grain, and discussed the existing problems and key points for future research. It merits further investigating the temporal (at different filling stages) and spatial (at different parts of a grain) distribution characteristics of the contents and compositions of amino acids in a grain during the filling, their physiological and biochemical mechanism, and cultivation regulation and its principle. Such a study is expected to gain new insight into the mechanism in the formation and distributions of amino acids in a rice grain, and explore a new way to increase the contents of amino acids, especially essential amino acids such as lysine, in milled rice. Table and Figures | Reference | Related Articles | Metrics

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Research progress regarding the function and mechanism of rice AP2/ERF transcription factor in stress response CHEN Yue, SUN Ming-Zhe, JIA Bo-Wei, LENG Yue, SUN Xiao-Li Acta Agronomica Sinica    2022, 48 (4): 781-790.   DOI: 10.3724/SP.J.1006.2022.12026 Abstract （467）   HTML （55）    PDF（pc） （277KB）（385）       Knowledge map    Save AP2/ERF (APETALA2/ethylene responsive factor) is a family of plant specific transcription factors that are widely involved in various biological processes including plant growth and development and stress responses. Rice is an important food crop in China, but it is severely affected by multiple adverse environmental factors during growth period. It has been found that AP2/ERF transcription factors play important roles in stress response in rice. In this paper, we reviewed the classification and structure architecture of rice AP2/ERF transcription factors and summarized the function and molecular mechanism of different AP2/ERF subfamilies in rice response to disease, drought, saline, and low temperature stresses. This study provides a reference for further interpretation of the molecular network of rice AP2/ERFs-mediated regulatory network in stress responses and their application potential for stress resistance improvement of rice cultivars. Table and Figures | Reference | Related Articles | Metrics

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Editorial: strengthening the research on the interaction between cultivated measures and environment/resource allocation of field economic crops to promote the development of industry with high efficiency and high quality ZHOU Guang-Sheng, WANG Jing, KUAI Jie, WANG Bo Acta Agronomica Sinica    2021, 47 (9): 1633-1638.   DOI: 10.3724/SP.J.1006.2021.04633 Abstract （320）   HTML （43）    PDF（pc） （225KB）（381）       Knowledge map    Save Reference | Related Articles | Metrics

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Genome-wide association study of pre-harvest sprouting traits in wheat XIE Lei, REN Yi, ZHANG Xin-Zhong, WANG Ji-Qing, ZHANG Zhi-Hui, SHI Shu-Bing, GENG Hong-Wei Acta Agronomica Sinica    2021, 47 (10): 1891-1902.   DOI: 10.3724/SP.J.1006.2021.01078 Abstract （383）   HTML （22）    PDF（pc） （5692KB）（372）       Knowledge map    Save To understand the genetic mechanism of wheat pre-harvest sprouting (PHS) in wheat breeding, it is significant to explore marker loci and candidate genes associated with PHS resistance using intact spikes. In this study, a total of 207 wheat varieties (lines) from China and 16,686 SNP markers were analyzed in wheat whole genome. The mixed liner model (Q + K) was used to analyze PHS phenotypic data in three environments. Genome-wide association study showed that there were abundant phenotypic variations in different environments and wheat varieties (lines). The coefficient of variation was 0.34 and 0.25, the polymorphic information content of value (PIC) was from 0.01 to 0.38, and the attenuation distance of whole genome LD was 3 Mb. The population structure and principal component analysis revealed that 207 wheat varieties (lines) could be divided into three subgroups. GWAS results indicated that 34 SNP markers were detected, which were significantly associated with pre-harvest sprouting at P < 0.001. They were located on chromosomes 3A, 3B, 4A, 4B, 5D, 6A, 6B, 6D, 7B, and 7D, and each explained 5.55%-11.63% of phenotypic variation. There were 16 markers loci detected in more than two environments, and the marker Np_Ex_c14101_22,012,676 on 6B chromosome detected in E1, E2, and average environment. Meanwhile, 13 candidate genes were screened out by mining association loci with large phenotypic effect value and stable inheritance. TraesCS3A01G589400LC, TraesCS6B01G138600/TraesCS6B01G516700LC/TraesCS6B01G548900LC, TraesCS6D01G103600, and TraesCS7B01G200100 could affect seed dormancy by regulating the sensitivity of endogenous ABA in plants. The F-box proteins were encoded by TraesCS3B01G415900LC, TraesCS6A01G144700LC, and TraesCS6B01G294800, which played major roles in plant hormone signal transduction, light signal transduction, and flower organ development. TraesCS6A01G108800, TraesCS6B01G138200/ TraesCS6B01G293700 encoded Myb transcription factor family. These candidate genes are important genes related to wheat sprouting. Table and Figures | Reference | Related Articles | Metrics

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Characteristics of carbon emission and approaches of carbon mitigation and sequestration for carbon neutrality in China’s crop production YAN Sheng-Ji, DENG Ai-Xing, SHANG Zi-Yin, TANG Zhi-Wei, CHEN Chang-Qing, ZHANG Jun, ZHANG Wei-Jian Acta Agronomica Sinica    2022, 48 (4): 930-941.   DOI: 10.3724/SP.J.1006.2022.12073 Abstract （306）   HTML （27）    PDF（pc） （777KB）（371）       Knowledge map    Save Crop production not only ensures national food security, but also is the main source of agricultural carbon emissions and an important pool of carbon sequestration. To clarify the characteristics of carbon emissions from crop production and discuss the approaches to reach the peak and neutrality in major agricultural areas can provide important scientific basis to the decision making of green and high-quality agricultural development and “dual-carbon” goal. Based on the national statistical data, this study compared and analyzed the characteristics of carbon emissions in crop planting regions in China, and presented the recommendations for carbon sequestration and greenhouse gas emission mitigation. The carbon emissions of crop production accounted for 45.5% of the national agricultural total carbon emissions in 2018, and the emissions of farmland methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) of diesel consumption accounted for 22.9%, 14.7%, and 7.9% of the total carbon emissions of agricultural production, respectively. In terms of the regional emissions, both the total carbon emission of crop production and the carbon emission per sowing area are higher in South than North China, with the highest emissions in East and central China and the greatest potential for emission mitigation. In the carbon emission from crop production, CH4 emission from rice fields accounts for the main part (50.3%) and is the focus of emission reduction. The annual carbon emission of crop production in China peaked in 2015, and then dropped down. It was mainly attributed to the decrease trend of rice sown area, agricultural nitrogen application rate, and diesel oil consumption. If the existing agricultural imports are not significantly affected, the carbon emissions in crop production have basically reached the peak. However, it is very difficult to achieve carbon neutrality in crop production if only by soil carbon sequestration of farmland, and it is necessary to consider both farmland emission reduction and carbon sequestration. On the premise of high and stable grain yield, the carbon neutrality of modern crop production should prioritize CH4 and N2O reduction, and fully exploit the integrated carbon sequestration potential of farmland ecosystems, such as straw utilization, combination of the use and protection of farmland, and construction of farmland forest network. Table and Figures | Reference | Related Articles | Metrics

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Research progress on genetic regulatory mechanism of seed color in soybean ( Glycine max) QIU Hong-Mei, CHEN Liang, HOU Yun-Long, WANG Xin-Feng, CHEN Jian, MA Xiao-Ping, CUI Zheng-Guo, ZHANG Ling, HU Jin-Hai, WANG Yue-Qiang, QIU Li-Juan Acta Agronomica Sinica    2021, 47 (12): 2299-2313.   DOI: 10.3724/SP.J.1006.2021.14022 Abstract （436）   HTML （49）    PDF（pc） （2315KB）（359）       Knowledge map    Save The color of soybean seeds is an important morphological marker and evolutionary trait. During the process of domestication, seed coat has gradually evolved from black to yellow, green, black, brown, and bicolor, and cotyledons has evolved from green to yellow. The dark seed coat contains anthocyanins, which are natural pigments with medicinal and nutritional values. Therefore, it is of great importance to study the genetic regulation mechanism of seed color for evolutionary theory, variety breeding, and practical application. The pigment content and composition of seeds result in diverse seed coat colors through complex molecular regulatory mechanisms. In this paper, we described the research progress on genetic loci, related genes, regulatory mechanisms, and flavonoid biosynthesis pathways that controlling the color of soybean seeds. Specifically, we introduced the 9 classical genetic loci I, R, T, O, W1, K1, G, D1, D2, and related molecular markers, as well as the interactions between the loci; 22 related genes that controlling seed color, and the regulatory mechanisms of some allelic variants; as well as the physiological functions of the flavonoid biosynthesis pathways and major metabolites involved in the related genes. The progress of researches on genetic regulation of the color of seed coat, seed hilum, and cotyledon in soybean was reviewed, in addition the regulatory network was mapped with genetic loci, genes, allelic regulatory mechanisms, and flavonoid metabolic pathways, in order to provide references for the quality of seed appearance and genetic improvement of anthocyanin components. Table and Figures | Reference | Related Articles | Metrics

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Identification of salt tolerance and screening of salt tolerant germplasm of mungbean ( Vigna radiate L.) at seedling stage HU Liang-Liang, WANG Su-Hua, WANG Li-Xia, CHENG Xu-Zhen, CHEN Hong-Lin Acta Agronomica Sinica    2022, 48 (2): 367-379.   DOI: 10.3724/SP.J.1006.2022.04283 Abstract （268）   HTML （29）    PDF（pc） （1348KB）（359）       Knowledge map    Save Soil salinization has become one of the important factors affecting agricultural production in China. It is of great significance to screen germplasm resources of mungbean [Vigna radiate (L.) Wilczek] for the utilization of salinized land. In the present study, the seedlings of 346 domestic and foreign collections of mungbean were exposed to 150 mmol L -1 NaCl. To evaluate the salt-tolerance of different mungbean genotypes at seedling stage, 12 indicators were calculated, including plant height, fresh weight of above-ground part, fresh weight of root, dry weight of above-ground part, dry root weight, root length, and root volume. Salt tolerance of each sample was comprehensively evaluated and classified by principal component analysis, membership function analysis, salt tolerance comprehensive evaluation, and cluster analysis; and the regression equation of salt tolerance prediction was established by stepwise regression analysis. The results revealed that there were significant differences between treatment group and control group in each trait evaluation index, and the salt tolerance coefficients of the 12 indicators were correlated to some content. Combining the classification of salt damage symptoms and the comprehensive evaluation results of salt tolerance, 26 mungbean germplasms with high salt tolerance, 65 germplasms with high salt tolerance, 74 germplasms with salt sensitive, and 18 germplasms with extremely salt sensitive were selected at seedling stage. Among them, 10 varieties such as C04125 from Jiangxi and C06310 from the Philippines had the strongest salt tolerance, which could be used as excellent resources for mungbean salt tolerance breeding. Above-ground fresh weight, root fresh weight, root dry weight, root length, root volume, and root branch number could be used to predict salt tolerance of mungbean at seedling stage. Table and Figures | Reference | Related Articles | Metrics

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Advances of QTL mapping for seed size related traits in peanut HUANG Li, CHEN Yu-Ning, LUO Huai-Yong, ZHOU Xiao-Jing, LIU Nian, CHEN Wei-Gang, LEI Yong, LIAO Bo-Shou, JIANG Hui-Fang Acta Agronomica Sinica    2022, 48 (2): 280-291.   DOI: 10.3724/SP.J.1006.2022.14046 Abstract （382）   HTML （26）    PDF（pc） （851KB）（357）       Knowledge map    Save Peanut is an important oil and economic crop in China. Currently, the domestic production of peanut remains far below the needs of consumers. Thus, further improving the yield per unit area is a crucial approach to meet the rising market demand. Seed size related traits are important agronomic traits in peanut, fundamentally contributing to improving yield per unit area. This review summarized the research progress on the regulatory pathways of seed size in plants, molecular markers, genetic linkage map construction, and QTL mapping of seed size related traits in peanut. We discussed the frontline challenges and opportunities for the coming researches of peanut seed related traits and the perspectives of yield improvement in peanut. Table and Figures | Reference | Related Articles | Metrics

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Research advance on optimizing annual distribution of solar and heat resources for double cropping system in the Yellow-Huaihe-Haihe Rivers plain ZHOU Bao-Yuan, GE Jun-Zhu, SUN Xue-Fang, HAN Yu-Ling, MA Wei, DING Zai-Song, LI Cong-Feng, ZHAO Ming Acta Agronomica Sinica    2021, 47 (10): 1843-1853.   DOI: 10.3724/SP.J.1006.2021.13012 Abstract （489）   HTML （33）    PDF（pc） （298KB）（355）       Knowledge map    Save Optimizing the distribution of annual solar and heat resources is an important way to improve the annual yield and resource use efficiency without increasing input for the winter wheat-summer maize of the Yellow-Huaihe-Haihe Rivers plain. During 1980s, the researchers began to explore ways to increase the efficiency utilization of solar and heat resources from the sowing/harvest adjustment, variety selection, and intensive cropping system innovation. Based on study of matching relation between crop growth and resources, a technological approach to optimize the distribution of solar and heat resources was put forward by strengthening the high photosynthetic efficiency of “C4 maize”. Then, the winter wheat and summer maize “double late” technology, winter wheat/spring maize/summer maize, winter wheat/spring maize/summer maize/autumn maize cropping systems were established, which realized high yield and high efficient utilization of resources. In this paper, we reviewed current theoretical and regulation approaches for optimizing distribution of solar and heat resources of double cropping system in the Yellow-Huaihe-Haihe Rivers plain. Then proposed a quantitative and optimal resources distribution method for double cropping system, and set up the unified quantitative indexes for resources distribution between winter wheat and summer maize, which could provide theory support for further increasing anniversary production and resource utilization efficiency of the Yellow-Huaihe-Haihe Rivers plain. Table and Figures | Reference | Related Articles | Metrics

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Identification of gene co-expression modules of peanut main stem growth by WGCNA WANG Ying, GAO Fang, LIU Zhao-Xin, ZHAO Ji-Hao, LAI Hua-Jiang, PAN Xiao-Yi, BI Chen, LI Xiang-Dong, YANG Dong-Qing Acta Agronomica Sinica    2021, 47 (9): 1639-1653.   DOI: 10.3724/SP.J.1006.2021.04223 Abstract （532）   HTML （56）    PDF（pc） （2038KB）（338）       Knowledge map    Save This study was investigated the difference of transcriptome using three different peanut varieties with high main stem by RNA-seq. Transcriptomics combined with weighted gene co-expression network analysis (WGCNA) was used to explore the hub genes related to main stem growth and the molecular mechanisms of morphological formation of peanut stems. Results showed that 5872 differential expressed genes (DEGs) were detected in the Df216 and Huayu 33 comparation group, while 6662 DEGs were detected in the Df216 and Shanhua 108 comparation group. GO analysis suggested that these DEGs were mainly involved in molecular function and biological process, including the primary and secondary cell wall organization and biogenesis, phenylpropanoid biosynthetic and metabolic process, lignin biosynthetic process, and cellulose synthase activity, respectively. There were 33 modules were identified by WGCNA, among which five modules (Grey60, Cyan, Darkolivegreen, Brown, and Blue) were highly significant association with main stem height. According to the connectivity of genes in modules, caffeoyl-CoA O-methyltransferase, transcription factorATAF2, WAT1 (walls are thin1), and GDSL esterase/lipase were the hub genes, respectively. The results of hub gene networks by weighted values indicated that coumaroylquinate 3’-monooxygenase, 4-coumarate-CoA ligase, shikimate O-hydroxycinnamoyltransferase, rapid alkalinization factor,COBRA-like protein, and zinc finger protein had high connections with ADRL3Lin the Grey60 module, while β-1,4-galactosyltransferase, LRR receptor-like serine/threonine-protein kinase, pectin acetylesterase, leucine-rich repeat extensin-like protein had high connections with TZB0A2 in the Brown module. The identification of co-expression modules and their hub genes, and the analysis of gene function and gene networks of key genes will be helpful for revealing the genetic basis of the main height in peanut. Table and Figures | Reference | Related Articles | Metrics

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Effects of elevated temperature and CO 2 concentration on growth and yield of maize under intercropping with peanut WANG Fei, GUO Bin-Bin, SUN Zeng-Guang, YIN Fei, LIU Ling, JIAO Nian-Yuan, FU Guo-Zhan Acta Agronomica Sinica    2021, 47 (11): 2220-2231.   DOI: 10.3724/SP.J.1006.2021.03018 Abstract （255）   HTML （9）    PDF（pc） （2184KB）（333）       Knowledge map    Save To clarify the effects of climate change on the growth development and yield of maize in the system of maize intercropping peanut, we performed the planting pattern of two rows maize intercropping and four rows peanut. Field experiments were carried out with TC (ambient temperature and ambient CO2 concentration), +T+C (elevated temperature and elevated CO2 concentration) in 2018, and TC, +TC (elevated temperature and ambient CO2 concentration), and +T+C in 2019, with two phosphorus levels of P0 (P2O5 0 kg hm-2) and P180 (P2O5 180 kg hm-2), respectively. The effects of elevated temperature and CO2 concentration on growth, dry matter accumulation and distribution, photosynthesis and yield of intercropping maize were studied. Results were as follows: (1) Compared with TC, the numbers of days from emergence to silking, silking to maturity, and emergence to maturity of intercropping maize under +TC were shortened respective by 4, 2, and 6 days. Compared with +TC, the number of days from emergence to silking of intercropping maize under +T+C was shortened by three days, while the numbers of days from silking to maturity, and emergence to maturity were increased by five days and two days. Compared with TC, the number of days from emergence to silking, and emergence to maturity of intercropping maize under +T+C was shortened by 4-7 days and 2-4 days, respectively; and the number of days from emergence to maturity was extended by 1-4 days. (2) The leaf area, net photosynthetic rate, and leaf area duration of intercropping maize were +T+C>+TC>TC before silking, +T+C>TC>+TC from silking to milk stage, and +T >+T+C>+TC after milk stage. Compared with TC, ear grain number and 100-grain weight of intercropping maize under +T+C were increased by 4.14%-65.70% and 1.70%-14.0%, respectively. (3) Compared with TC, the dry matter of intercropping maize at maturity stage increased by 7.39%-21.30% and the yield increased by 19.18%-28.07% under +TC. The dry matter and yield of intercropping maize increased by 10.0%-57.7% and 4.41%-52.00% under +T+C, respectively. The grain yield of intercropping maize was improved by applying phosphorus after increasing temperature and CO2 concentration. These results indicated that elevated temperature and CO2 concentration could promote dry matter accumulation and grain yield improvement by increasing net photosynthetic rate, leaf area index, and leaf area duration of intercropping maize at early growth stage, shortening vegetative growth period, prolonging grain filling time, and increasing ear grain number and grain weight per panicle. Elevated temperature and CO2 concentration had mutual promoting effect on the growth of intercropping maize before silking stage, while increasing CO2 concentration could make up for the inhibiting effect of increasing temperature on the growth of intercropping maize after silking. Table and Figures | Reference | Related Articles | Metrics

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A critical review on the principles and procedures for cultivar development and evaluation YAN Weikai Acta Agronomica Sinica    2022, 48 (9): 2137-2154.   DOI: 10.3724/SP.J.1006.2022.11105 Abstract （163）   HTML （11）    PDF（pc） （890KB）（328）       Knowledge map    Save Plant breeding plays an indispensable role in meeting the increasing need for food and comfort of the mankind in a changing climate. Numerous concepts and procedures aiming at improving breeding efficiency have been put forward, such as various strategies for dealing with genotype by environment interaction, stability analyses, mega-environment analyses, experimental designs and analyses, biplot analyses, and selection indices. In addition, genomic selection has evolved into a stage that plant breeders must consider and cannot ignore. It is of practical importance to understand the relationships among these concepts and procedures, their usefulness, drawbacks, and pitfalls, as well as their place in the theoretical framework of plant breeding and genotype evaluation. Based primarily on personal research and experience, this article attempted to develop a systematic narrative on the principles, key concepts, and analytic procedures related to cultivar development and evaluation, with demonstrations using real-world data. Table and Figures | Reference | Related Articles | Metrics

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Genome-wide association analysis and candidate gene selection of yield related traits in rice YANG Fei, ZHANG Zheng-Feng, NAN Bo, XIAO Ben-Ze Acta Agronomica Sinica    2022, 48 (7): 1813-1821.   DOI: 10.3724/SP.J.1006.2022.12047 Abstract （188）   HTML （20）    PDF（pc） （4541KB）（323）       Knowledge map    Save Rice is the most important food crop for more than half of the world’s population, and the cultivation of rice varieties with high and stable yield is crucial for solving the world’s food problems. In this study, 226 rice core materials with relatively consistent growth stage were selected from “3K Rice Genome Project” and 2429 kb of high density genotype and 10 agronomic traits including growth period, plant height, effective panicle number, panicle length, spikelet density, seed setting rate, thousand-grains weight, yield per plant, spikelet per panicle, and grains per panicle were investigated by genome-wide associate study combined with 2429 kb of high-density genotype data. A total of 43 loci significantly associated with main agronomic traits were identified, including seven known loci, such as qRGP7.2, qPH12, qPL6.2, qSD6.2, qTGW1.1, qGP1, and qGP5.2. Six candidate genes were screened out, including LOC_Os12g18760 related to plant height, LOC_Os03g33530 related to effective panicle number, LOC_Os06g30940 related to panicle length, LOC_Os01g49810 related to thousand grains weight, LOC_Os09g25260 related to yield per plant, and LOC_Os09g32620 related to spikelet density and spikelet per panicle. These results provide important gene resources and the theoretical reference for genetic improvement of rice yield. Table and Figures | Reference | Related Articles | Metrics

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Genome wide association analysis of petiole angle based on 783 soybean resources ( Glycine max L.) CHEN Ling-Ling, LI Zhan, LIU Ting-Xuan, GU Yong-Zhe, SONG Jian, WANG Jun, QIU Li-Juan Acta Agronomica Sinica    2022, 48 (6): 1333-1345.   DOI: 10.3724/SP.J.1006.2022.14102 Abstract （322）   HTML （25）    PDF（pc） （7956KB）（317）       Knowledge map    Save Petiole angle is one of the important factors that affects the high-efficiency light posture of plants. It is very important to improve soybean plant architecture by adjusting the leaf angle petioles. Soybean petiole angle is a quantitative trait, which is limited to QTLs mapping for most studies up to date. The reported gene GmILPA1controlling leaf petiole angle gene was cloned from mutants. Identification of more regulatory genes and elite alleles is urgent both for the clarification of genetic mechanism for petiole angle and its breeding utilization. In this study, 783 and 690 soybean germplasms were phenotypic for petiole angle in Hainan and Beijing in 2019 and 2020, respectively, and genome-wide associated study (GWAS) were performed using genome-wide distributed SNPs. Results showed that the petiole angle at different nodes (top, middle, and bottom nodes) were in normal distribution, suggesting that the trait of typical quantitative was inheritance. A total of 325 SNPs associated with petiole angle were identified by two-point GWAS analysis in two years, including 51, 230, 10, and 34 SNPs for petiole angles of the top, middle, bottom, and mean value of different nodes, respectively. Three candidate genes (Glyma.05G059700: auxin regulatory protein, Glyma.06G076900: AFR, and Glyma.06G076000: COP9) were obtained by LD block analysis. Transcriptional analysis revealed that all these three candidate genes had high expression level in shoot apical meristem (SAM), however, high expression level were also identified in leaf for Glyma.06G076900, leaf and stem for Glyma.06G076000. Table and Figures | Reference | Related Articles | Metrics

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Effects of side deep placement of nitrogen on rice yield and nitrogen use efficiency HUANG Heng, JIANG Heng-Xin, LIU Guang-Ming, YUAN Jia-Qi, WANG Yuan, ZHAO Can, WANG Wei-Ling, HUO Zhong-Yang, XU Ke, DAI Qi-Gen, ZHANG Hong-Cheng, LI De-Jian, LIU Guo-Lin Acta Agronomica Sinica    2021, 47 (11): 2232-2249.   DOI: 10.3724/SP.J.1006.2021.02086 Abstract （259）   HTML （13）    PDF（pc） （318KB）（316）       Knowledge map    Save Lateral deep fertilization is an efficient, high-quality, and safe cultivation technology of rice mechanical transplanting. In order to improve the technical system of lateral deep fertilization, we investigated the effects of different fertilization methods on rice yield and nitrogen use efficiency under the condition of lateral deep fertilization. In this study, Nanjing 9108 and Nanjing 5718, the representative varieties of quality and delicious rice of Jiangsu, were used as materials. Four different lateral deep fertilization methods were arranged, including 100% base fertilizer side deep application FM1 (fertilization method 1), 70% base fertilizer side deep application + 30% tillering fertilizer FM2 (fertilization method 2), 70% base fertilizer side deep application + 30% panicle fertilizer FM3 (fertilization method 3), and 35% base fertilizer side deep application + 35% tillering fertilizer + 30% panicle fertilizer FM4 (fertilization method 4). In addition, the conventional fertilization method and no nitrogen treatment were added. The effects of different treatments on rice yield, leaf area index, photosynthetic potential, dry matter accumulation, population growth rate, and nitrogen use efficiency were compared. The results revealed that the yield of FM3 and FM4 were higher than those of other treatments. The main reason was that the spikelet number of the population was significantly higher than that of other treatments on the basis of stable panicle number. The leaf area index and dry matter accumulation of FM3 treatment were higher in the middle and late growth stages, especially from heading to maturity stage. Nitrogen accumulation of FM3 was less before jointing stage, but nitrogen accumulation after jointing stage and the total nitrogen uptake during the whole growth period were significantly higher than those of other treatments. Moreover, the nitrogen agronomic utilization rate, nitrogen physiological utilization rate, nitrogen absorption utilization rate, and nitrogen partial productivity of FM3 were significantly higher than those of the other treatments. At the same time, compared with CFM and FM4, FM3 can reduce fertilization times by 1-2 times, save labor and cost, and is conducive to large-scale production. It is a high-yield, simple and efficient fertilization method for rice. Table and Figures | Reference | Related Articles | Metrics

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Enhancement of plant variety protection and regulation using molecular marker technology XU Yunbi, WANG Bing-Bing, ZAHNG Jian, ZHANG Jia-Nan, LI Jian-Sheng Acta Agronomica Sinica    2022, 48 (8): 1853-1870.   DOI: 10.3724/SP.J.1006.2022.23001 Abstract （413）   HTML （53）    PDF（pc） （834KB）（313）       Knowledge map    Save Plant variety protection is one of the important approaches for plant intellectual property protection. The distinctness, uniformity and stability (DUS) and essentially derived variety (EDV) are two major concepts in plant variety protection. DUS-EDV has been evaluated largely through morphological traits and pedigrees at the very beginning, to an integrated approach using morphological traits, pedigrees and molecular marker information and now to a stage largely driven by molecular diagnostics. Molecular diagnostic technology has been evolved from RFLP to SSR and SNP marker systems. The liquid SNP chip, represented by genotyping by target sequencing through capture in solution, has advantages of low cost, high flexibility in marker combinations and wide suitability for DUS-EDV evaluation across plant species. There are two important strategies in DUS-EDV evaluation, one being examined based on the analysis and comparison at the whole genome level and the other being examined at specific genomic regions for target functional loci associated with important phenotypes. Evaluation criteria should be established separately for DUS and EDV. The former can be evaluated based on the criteria constructed for specific fingerprint maps, haplotypes, unique alleles, genomic regions, target functional markers, minimum genetic homozygosity, and within-variety variation, whereas the latter can be examined by the genetic similarity between the potential EDV and check variety estimated using a large number of molecular markers evenly distributed across the genome, rather than by the number of markers. The number and the genomic coverage of molecular markers are two key factors affecting the efficiency and reliability in DUS and EDV assessment. Using only a small number of markers in such assessment will likely result in a large sampling error for the estimates. The threshold of genetic similarity required for distinguishing EDV and non-EDV can vary greatly across plant species and with the levels of plant variety protection. After reviewed the current status of plant variety protection across countries, the authors proposed that a national consultant expert committee should be established for consistent support to implement and improve DUS-EDV system, and an official database system should be constructed for public service and comparison of variety DNA fingerprint data to facilitate innovative activities in plant breeding. Table and Figures | Reference | Related Articles | Metrics

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Research progress of crop diseases monitoring based on reflectance and chlorophyll fluorescence data JING Xia, ZOU Qin, BAI Zong-Fan, HUANG Wen-Jiang Acta Agronomica Sinica    2021, 47 (11): 2067-2079.   DOI: 10.3724/SP.J.1006.2021.03057 Abstract （342）   HTML （32）    PDF（pc） （520KB）（305）       Knowledge map    Save Crop diseases are biological disasters that affect grain production and quality. The infestation of diseases consumes the nutrients and water, disrupts its normal life process, and causes changes in the internal physiological and biochemical state and external appearance of the crop. Canopy reflectance spectrum can detect crop population structure information well, and chlorophyll fluorescence data can sensitively reflect changes in crop photosynthetic physiology, both methods are capable of detecting crop diseases via remote sensing technology. This article outlined the current research status of crop diseases detection based on reflectance spectrum through remote sensing technology from the aspects of monitoring methods and monitoring scales, summarized the research progress of using active fluorescence, passive fluorescence and coordinated solar-induced chlorophyll fluorescence and reflectance spectroscopy to monitor crop diseases, analyzed the advantages and disadvantages of reflectance spectrum and chlorophyll fluorescence data in crop disease early warning detection, and discussed the possible problems in the remote sensing detection of crop diseases. On the basis, we made a prospect for the development of remote sensing monitoring crop diseases. This paper provides an important reference for the subsequent applications of crop diseases detection based on reflectance spectrum and chlorophyll fluorescence data. Table and Figures | Reference | Related Articles | Metrics

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Effects of nutrient uptake and utilization on yield of maize-legume strip intercropping system YANG Huan, ZHOU Ying, CHEN Ping, DU Qing, ZHENG Ben-Chuan, PU Tian, WEN Jing, YANG Wen-Yu, YONG Tai-Wen Acta Agronomica Sinica    2022, 48 (6): 1476-1487.   DOI: 10.3724/SP.J.1006.2022.13017 Abstract （250）   HTML （18）    PDF（pc） （1677KB）（301）       Knowledge map    Save To clarify the difference of nutrient uptake and utilization to yield advantage between maize-soybean relay intercropping and maize-peanut intercropping, we conducted a field experiment for two consecutive years. The results were obtained by comparing nitrogen (N), phosphorous (P), and potassium (K) absorption efficiency and utilization in the intercropping with sole cropping. The results showed that land equivalent ratio (LER) of maize-soybean relay intercropping was 1.16-1.72, which had the advantage of intercropping yield, but the LER of maize-peanut intercropping was 0.89-1.13, which had no obvious yield disadvantage. In maize-soybean relay intercropping system, the amount of N, P, and K uptake was higher than that of the corresponding sole cropping by 32.60%-54.22%, 27.35%-34.64, and 17.74%-24.42%, respectively, but the N utilization efficiency was lower by 21.99%-42.07%. The contributions of the N, P, and K uptake efficiencies to LER were 0.34-0.62, 0.31-0.46, and 0.22-0.32, and the utilization efficiencies contributions were -0.11 to -0.35, -0.03 to -0.31, and -0.11 to 0.22, respectively. In maize-peanut intercropping system, the amount of N, P, and K uptake was higher than that of the corresponding sole cropping by -7.86% to 31.58%, 23.09%-46.52%, and 1.60%-55.48%, respectively, and the N utilization efficiency was higher by 7.55-26.60. The contributions of the N, P and K uptake efficiencies to LER were 0-0.22, 0.05-0.27, and -0.11-0.32, respectively, and the utilization efficiencies contributions were -0.25-0.19, -0.32-0.11, and -0.47-0.32, respectively. In conclusion, yield advantage of maize-soybean relay intercropping was mainly from enhanced nutrient uptake efficiency, but there was no obvious yield advantage in maize-peanut intercropping mainly due to relatively less contribution of nutrient uptake to yield advantage. Table and Figures | Reference | Related Articles | Metrics

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Phylogeny of wild Setaria species and their utilization in foxtail millet breeding ZHAO Mei-Cheng, DIAO Xian-Min Acta Agronomica Sinica    2022, 48 (2): 267-279.   DOI: 10.3724/SP.J.1006.2022.14047 Abstract （392）   HTML （46）    PDF（pc） （526KB）（298）       Knowledge map    Save Foxtail millet (Setaria italica) was domesticated from the wild ancestor, green foxtail (S. viridis), about ten thousand years ago in China. Foxtail millet belongs to Setaria genus, which includes about 125 species of panicoid grasses worldwide, and 15 species of them in China varied from diploid to octoploid. Currently, six genomes in the Setaria genus have been identified by GISH (genomic in situ hybridization). Molecular phylogenetic analyses show that the Setaria genus is polyphyletic, in line with the characteristic of diversified genomes. Phylogeny of Setaria genus reveal that foxtail millet is most closely related with green foxtail, and then S. fabrei and S. verticillata, and that A genome of S. italica/S. viridis appears to be closer to B genome of S. adhaeran and C genome of S. grisebachii than the other known genomes. For utilization of wild species resources, foxtail millet breeders have successfully introduced the naturally mutated herbicide-resistant genes from green foxtail into cultivars, resulting in the herbicide-resistant foxtail millet variety. Here, we review the recent advances of wild species of foxtail millet in species classification, genome constitution and phylogenetic relationships, and highlight the utility of the wild species resources for breeding and domestication of foxtail millet. We also discuss the potentials of the wild Setaria species in discovery of domestication genes and breeding in foxtail millet in the future. Table and Figures | Reference | Related Articles | Metrics

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Physiological mechanisms of pre-anthesis waterlogging priming on waterlogging stress tolerance under post-anthesis in wheat MA Bo-Wen, LI Qing, CAI Jian, ZHOU Qin, HUANG Mei, DAI Ting-Bo, WANG Xiao, JIANG Dong Acta Agronomica Sinica    2022, 48 (1): 151-164.   DOI: 10.3724/SP.J.1006.2022.11005 Abstract （252）   HTML （15）    PDF（pc） （1344KB）（296）       Knowledge map    Save In order to investigate the responses and mechanisms of different wheat varieties to waterlogging stress and waterlogging priming, waterlogging priming was conducted for two days at the four-leaf and six-leaf stages, respectively, and waterlogging stress was performed for five days at post-anthesis using wheat varieties with different responses to waterlogging stress and waterlogging priming as experimental materials. Results showed that waterlogging stress significantly reduced chlorophyll content (SPAD) and actual photochemical efficiency (ΦPSII), inhibited the accumulation of post-anthesis photosynthetic assimilation accumulation (PAA), decreased kernel weight and grain yield. Compared with the waterlogging-sensitive varieties, the waterlogging-tolerance varieties could maintain higher SPAD, ΦPSII and PAA, and higher activities of superoxide dismutase (SOD), Catalase (CAT), ascorbate peroxidase (APX) and glutathione reductase (GR), lower contents of H2O2, O2?production rate and malondialdehyde (MDA) under post-anthesis waterlogging stress. Compared with non-primed plants, primed plants could maintain higher chlorophyll fluorescence performance and higher activities of antioxidant enzymes. Compared with the waterlogging priming-insensitive varieties, the priming-sensitive varieties increased SPAD (8.8%) and ΦPSII (17.6%), decreased the non-regulated energy dissipation ΦNO (10.7%) and the regulation energy dissipation ΦNPQ (16.5%), increased the activities of SOD (15.8%), CAT (17.8%), APX (8.9%) and GR (30.7%), increased the contents of total soluble sugar (17.5%) and sucrose (21.6%), increased remobilization efficiency of pre-anthesis stored dry matter (REP, 20.0%) and PAA (10.8%). The waterlogging tolerant varieties could maintain higher photosynthesis rate, dry matter translocation capacity and activities of antioxidant enzymes. Compared with waterlogging sensitive varieties, the increase amplitude of photosynthetic ability and antioxidant enzyme activity of priming-sensitive cultivars was higher under waterlogging stress. Table and Figures | Reference | Related Articles | Metrics

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Different responses of rice cultivars to salt stress and the underlying mechanisms YAN Jia-Qian, GU Yi-Biao, XUE Zhang-Yi, ZHOU Tian-Yang, GE Qian-Qian, ZHANG Hao, LIU Li-Jun, WANG Zhi-Qin, GU Jun-Fei, YANG Jian-Chang, ZHOU Zhen-Ling, XU Da-Yong Acta Agronomica Sinica    2022, 48 (6): 1463-1475.   DOI: 10.3724/SP.J.1006.2022.12027 Abstract （224）   HTML （21）    PDF（pc） （1151KB）（295）       Knowledge map    Save The objective of this study is to elucidate the responses of physiological traits and yield with different salt stress to salt-tolerant and salt-susceptible rice cultivars. Five salt-tolerant rice cultivars and two salt-susceptible rice cultivars were grown in pots with five different salt concentration levels including 0, 1, 2, 2.5, and 3 g kg-1 of per pot for two years. Results showed that the yields of salt-tolerant cultivars were less reduced than that of salt-susceptible cultivars, and salt-tolerant cultivars was able to tolerate higher salt concentration of 2.5 g kg-1. Salt-tolerant varieties produced higher grain yield mainly due to the greater total spikelets per area and higher filled grain percentage under salt stress. Salt-tolerant rice cultivars also had higher activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), higher contents of osmotic substances such as fructose, trehalose, and sorbitol, and higher K+/Na+ ratio from mid-tillering to heading. The crop growth rate from tillering to jointing and from heading to maturity, and photosynthetic rate at heading stage were higher in salt-tolerant cultivars than in salt-susceptible cultivars. The above results revealed that the differences in grain yields between salt-tolerant and salt-susceptible rice varieties were mainly due to the performances of physiological traits at mid-tillering, panicle initiation, and heading stages. These growth stages were the key stages that determined the number of panicles, spikelets per panicle, and the percentage of filled grains. The better physiological traits in the salt-tolerant rice varieties during key stages were the basis for higher grain yield. The results of this study could be helpful for the physiological researches and the breeding of salt-tolerant rice. Table and Figures | Reference | Related Articles | Metrics

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Characterization and genetic mapping of a classic-abortive-type recessive genic-male-sterile mutant ap90 in rice ( Oryza sativa L.) CHEN Chi, CHEN Dai-Bo, SUN Zhi-Hao, PENG Ze-Qun, Adil Abbas, HE Deng-Mei, ZHANG Ying-Xin, CHENG Hai-Tao, YU Ping, MA Zhao-Hui, SONG Jian, CAO Li-Yong, CHENG Shi-Hua, SUN Lian-Ping, ZHAN Xiao-Deng, LYU Wen-Yan Acta Agronomica Sinica    2022, 48 (7): 1569-1582.   DOI: 10.3724/SP.J.1006.2022.12044 Abstract （245）   HTML （50）    PDF（pc） （12430KB）（290）       Knowledge map    Save In this study, we obtained a stable male sterile mutant abortive pollen 90 (ap90) from the mutant library of Zhonghui 8015 (wild-type, WT), an indica restorer line, induced by Ethyl Methy Sulfone (EMS). Compared to the WT, the ap90 mutant displayed no significant differences in plant height, plant type, tiller number, heading date and other agronomic traits, but the anthers were thinner, light creamy yellow and pollen grains were completely abortive. Semi-thin sections observation of anther development at different stages showed that the ap90 mutant carried an abnormal development process of anther wall cells. Namely, the tapetum cell degradation was obviously abnormal, the microspore cells could not form a normal pollen wall structure during mitosis and the starch filling process was blocked which eventually resulted in the degradation of microspores into threadlets and failure of anther dehiscence. Scanning electron microscopic (SEM) observations of the anther surface and pollen exine suggested that the anther epidermis of mutant ap90 were shrunk and covered by more compactly arranged cuticles. The shape of Ubisch distributed on the inner surface of anther locule were irregular, closely arranged and disordered. The pollen grains were shriveled and the sporopollenin on the pollen exine were abnormally arranged. Genetic analysis showed that the ap90 phenotype was controlled by a pair of recessive nuclear genes. Gene preliminary mapping located the mutation site into a 491.73 kb interval between RM21421 and RM21435 on the long arm of rice chromosome 7. Further Mut-Map sequencing analysis confirmed that there was a 37 bp deletion and a following single base substitution in the second exon region of LOC_Os07g22850 in the ap90 mutant, which resulted in the shifted coding sequence, prematurely terminated transcription and translation, leading to the entire abortive pollen and sterile spikelet in the ap90 mutant. Expression pattern analysis results demonstrated that the OsAP90 gene was specifically expressed in anthers and the OsAP90 protein was mainly located in the endoplasmic reticulum (ER). The qPCR results suggested that the relative expression level of many male sterility-related genes in the ap90 mutant was affected by the mutation site, which further proved that OsAP90 played an important role during the formation of Ubisch and pollen wall in rice anther development. Table and Figures | Reference | Related Articles | Metrics

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Dissecting the genetic architecture of lodging related traits by genome-wide association study and linkage analysis in maize YU Rui-Su, TIAN Xiao-Kang, LIU Bin-Bin, DUAN Ying-Xin, LI Ting, ZHANG Xiu-Ying, ZHANG Xing-Hua, HAO Yin-Chuan, LI Qin, XUE Ji-Quan, XU Shu-Tu Acta Agronomica Sinica    2022, 48 (1): 138-150.   DOI: 10.3724/SP.J.1006.2022.03072 Abstract （306）   HTML （22）    PDF（pc） （752KB）（289）       Knowledge map    Save Lodging is one of the main factors affecting the grain yield and mechanized harvesting in maize. Dissecting the genetic basis of lodging related traits can provide a theoretical basis for high yield and mechanized harvest breeding of maize. In this study, genome-wide association study (GWAS) and linkage analysis were combined to identify the significant loci interrelated with lodging related traits using 153 inbred lines from China and abroad. We detected 5, 14, 16, and 21 SNPs significant SNPs related to stem strength, plant height, ear height, and ear height-to-plant height ratio, respectively. Among these significant SNPs, the maximum effect value of a single site was 13.24. Twenty-one QTLs related to lodging related traits were identified by linkage analysis, which explaining the phenotypic variations of 3.86%-16.58% in F5 population constructed by KA105 and KB020. Further, we noticed that two QTL intervals were coincided with the candidate intervals of association analysis. Finally, GRMZM2G105391, GRMZM2G014119, and GRMZM2G341410 candidate genes related to cell wall biosynthesis, cell division and elongation were predicted by functional annotation for these candidate regions. These results can provide a new reference for further analysis of the genetic basis of lodging resistance in maize. Table and Figures | Reference | Related Articles | Metrics

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Phenotypic characterization and gene mapping of an early senescence leaf H5( esl-H5) mutant in rice ( Oryza sativa L.) ZHENG Chong-Ke, ZHOU Guan-Hua, NIU Shu-Lin, HE Ya-Nan, SUN wei, XIE Xian-Zhi Acta Agronomica Sinica    2022, 48 (6): 1389-1400.   DOI: 10.3724/SP.J.1006.2022.12035 Abstract （192）   HTML （11）    PDF（pc） （10822KB）（288）       Knowledge map    Save A stable mutant esl-H5 (early senescence leaf H5) was identified from the mutant library of japonica rice Huaidao 5 population induced by ethyl methane sulfonate (EMS) treatment. The mutant was normal at seedling stage. However, the lower leaves in esl-H5 mutant displayed premature senescence at about 50 days after sowing. Compared with the wild type (WT), the heading date of the esl-H5 mutant was delayed, while agronomical traits including plant height, panicle length, grain number per panicle, effective tiller numbers, and 1000-grain weight were significantly reduced. Moreover, chlorophyll content was also decreased in esl-H5 mutant. Genetic analysis indicated that the early senescence trait in esl-H5 mutant was controlled by a single recessive gene. ESL-H5 gene was localized on chromosome 1 using molecular marker. MutMap analysis further revealed that one nucleotide G to A replace occurred in the last exon of Os01g0533000 gene which encodes callose synthase. The G to A replace in the ESL-H5 introduced a premature stop codon. Phylogenetic analysis showed that ESL-H5 was homology with Arabidopsis AtGSL7 (Glucan Synthase-Like 7). At tillering stage, the contents of soluble sugar and starch were significantly increased in the leaves of the esl-H5 mutant compared with those of the WT. These results implied that the mutation of ESL-H5 affected the transport of photosynthetic products, resulting in premature leaf senescence phenotypes. The qRT-PCR analysis revealed that the expression levels of disease resistance-related genes PR1a, PR1b, PR2, PR4, PR5, and PR10 in esl-H5 mutant were higher than those in WT, which was consistent with the observation that esl-H5 mutant improved bacterial blight resistance. The present results lay the foundation for studying the roles of sugar signal in regulating rice senescence and disease resistance. Table and Figures | Reference | Related Articles | Metrics

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Cloning and functional identification of gene OsATS in rice LI Xiao-Xu, WANG Rui, ZHANG Li-Xia, SONG Ya-Meng, TIAN Xiao-Nan, GE Rong-Chao Acta Agronomica Sinica    2021, 47 (10): 2045-2052.   DOI: 10.3724/SP.J.1006.2021.02079 Abstract （278）   HTML （15）    PDF（pc） （4705KB）（281）       Knowledge map    Save The plant embryo specific protein ATS3 is closely related to osmotic stress response in plants. Here, the stress resistance related gene OsATS was preliminarily studied in rice. Fluorescence quantitative PCR showed that the relative expression level of OsATS increased significantly after salt stress in rice. The overexpression vector of OsATS was constructed and transformed into Arabidopsis thaliana. The stress resistance test revealed that the overexpression of OsATS gene could significantly improve the salt tolerance of Arabidopsis thaliana at germination and adult stages. After that, the overexpression vector p1300-35s:OSATS and RNA interference vector pTCK303-OsATS-RNAi were transferred into rice. The stress tolerance analysis indicated that the salt tolerance of OsATS overexpression rice lines significantly increased at germination stage and seedling stage, while the salt tolerance of OsATS RNAi rice lines significantly decreased. Results of qRT-PCR and physiological index detection demonstrated that the relative expression levels of OSATS gene might regulate the protein content of proline and LEA cells by regulating the expression of OsP5CS1, OsLEA3-1 and OsPDH, thus affecting the salt tolerance in rice. This study preliminarily revealed the stress resistance function of OSATS gene, which laid a foundation for improving rice stress resistance by adjusting the relative expression level of OSATS gene. Table and Figures | Reference | Related Articles | Metrics

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Root system architecture analysis and genome-wide association study of root system architecture related traits in cotton SUN Si-Min, HAN Bei, CHEN Lin, SUN Wei-Nan, ZHANG Xian-Long, YANG Xi-Yan Acta Agronomica Sinica    2022, 48 (5): 1081-1090.   DOI: 10.3724/SP.J.1006.2022.14067 Abstract （232）   HTML （33）    PDF（pc） （4931KB）（279）       Knowledge map    Save Root is the main organ of plants that absorbs water and nutrients. The growth of the root system will directly affect the absorption and utilization of nutrients, the resistance to abiotic stress and finally the yield of cotton. In this study, a natural population of 220 upland cotton accessions and a chromosomal segment substitution line (CSSL) population with 325 lines, derived from the crossing and backcrossing of Gossypium barbadense acc. 3-79 with G. hirsutum cv. ‘Emian 22’ were selected to collect the major root phenotypic traits. Four major traits, namely main root length (MRL), root fresh weight (RFW), root dry weight (RDW) and lateral root angle (LRA) were investigated, and genome-wide association analysis (GWAS) was performed for four root traits in natural populations in combination with genome resequencing. The results showed that the four root traits of the natural population are all in line with normal distribution, and the CSSL population were all in skewed distribution. The mean value of root index of CSSL population was higher than that of natural population. A total of 2,714,140 SNP was obtained from the resequencing data of the natural population. The principal component analysis (PCA) showed that the RFW and MRL could be used as two indexes for cotton root classification, through which the cotton root could be divided into nine types in each population. The analysis of population structure demonstrated that the natural population can be divided into five subgroups. Genome-wide association analysis rrevealed that two association sites were simultaneously associated by RFW and RDW in natural populations. The results of this study provide a theoretical basis for further research on root system architecture (RSA) and its genetic mechanism, and it is also of great significance to cotton breeding of abiotic stress resistance. Table and Figures | Reference | Related Articles | Metrics

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Research progress of photosynthetic physiological mechanism and approaches to application in dense planting maize GUO Yao, CHAI Qiang, YIN Wen, FAN Hong Acta Agronomica Sinica    2022, 48 (8): 1871-1883.   DOI: 10.3724/SP.J.1006.2022.13024 Abstract （336）   HTML （46）    PDF（pc） （767KB）（278）       Knowledge map    Save To ensure enough crop production of limited land area is important to food security. The key to solve this issue is to increase yield per unit area. Dense planting is an effective agronomic management practice to increase yield per unit area, photosynthetic rate would not be decreased or even improved by increasing planting density moderately, and then enhancing the yield per unit area. It is a key research focus on revealing the mechanism of photosynthetic physiology for improving yield per unit area by dense planting condition of maize. Dense planting would lead to change photosynthetic characteristics, so controlling the physiological factors that restricts photosynthesis is essential for increasing yield. Tap the photosynthetic physiologic potential for maize condition is physiological basis to ensure yield, which plays an important role in addressing food security issues. Therefore, this review focuses on the changes of the research methods and ideas in photosynthetic physiology, and the research status of the photosynthetic physiological response of maize adapted to dense planting and related agronomic regulation pathways at home and abroad, based on previous research results, so as to provide the theoretical and technical methods basis for photosynthetic physiology research. Based on the development trend of modern technology, it is believed that tapping photosynthetic potential and narrowing the gap between photosynthetic potential and actual photosynthetic efficiency are still the main goals of maize dense planting research by traditional research methods combined with molecular biology techniques in the future. In further study, research emphasis should be to investigate the responses of differential expression of photosynthetic physiological function genes to cultivation measures, clarifying the relationship and interaction between agronomic management practice and information expression of photosynthetic-related genes in densely planted maize, enhancing photosynthetic potential for maize via agronomic management practice and molecular biology technology, in order to provide photosynthetic physiological theory and practice to support for maize dense planting. Table and Figures | Reference | Related Articles | Metrics

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Genome-wide association study of seed density and its related traits in Brassica napus L. LEI Wei, WANG Rui-Li, WANG Liu-Yan, YUAN Fang, MENG Li-Jiao, XING Ming-Li, XU Lu, TANG Zhang-Lin, LI Jia-Na, CUI Cui, ZHOU Qing-Yuan Acta Agronomica Sinica    2021, 47 (11): 2099-2110.   DOI: 10.3724/SP.J.1006.2021.04245 Abstract （205）   HTML （19）    PDF（pc） （6958KB）（271）       Knowledge map    Save Seed density reflects the accumulation characteristics of crop photosynthetic products in the grains, which plays an important role in the thousand-seed weight of rape. Selecting high seed density germplasm resources and studying the genetic characteristics of seed density are very important in the breeding of rapeseed. A natural population containing 187 Brassica napus L. varieties (lines) with different genetic backgrounds was used as plant materials to determine the seed density and its related traits (thousand-seed weight and seed volume) in the two environments. Genome-wide association study was carried out based on the optimal model and the candidate genes associated with seed density, thousand-seed weight, and seed volume was predicted. In the two years, there were significant differences in the seed density and its related traits among 187 materials at P < 0.05, and three materials with high seed density or thousand-seed weight were selected. A total of 24 SNP loci, that were significantly associated with seed density, seed weight, and seed volume, were identified by GWAS, which explained the phenotypic variation of 8.21%-10.40%. Haplotype analysis was used to determine the block interval of the SNP sites. The blocks containing 11 SNPs covered 12 candidate genes, which mainly encoded transcription factors such as WOX8, HAIKU1, AP2/ERF transcription factors, Dof family-zinc finger superfamily, BZR1 transcription factors, enzymes such as BKI1, KAT2, CEL1, UBP15, DNA binding proteins, and hormone response proteins such as ARF2 and J3. These results provide the theoretical basis for the development of high seed density rape varieties and the functional research of subsequent genes. Table and Figures | Reference | Related Articles | Metrics

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Effect of water and nitrogen reduction on main photosynthetic physiological parameters of film-mulched maize no-tillage rotation wheat XU Long-Long, YIN Wen, HU Fa-Long, FAN Hong, FAN Zhi-Long, ZHAO Cai, YU Ai-Zhong, CHAI Qiang Acta Agronomica Sinica    2022, 48 (2): 437-447.   DOI: 10.3724/SP.J.1006.2022.01093 Abstract （240）   HTML （23）    PDF（pc） （1747KB）（268）       Knowledge map    Save The effect of no-tillage combined with water and nitrogen reduction of mulching maize on the stability and increase of wheat yield has been verified, but the research of the photosynthetic physiological mechanism of its formation is still relatively weak. From 2018 to 2020, the split zone design was adopted, and two farming methods of film-mulched corn no-tillage (NT) and traditional tillage (CT) was arranged with two irrigation levels of traditional irrigation (I2, 2400 m 3 hm ?2) and traditional irrigation reduce 20% (I1, 1920 m 3 hm ?2) and three nitrogen application levels of 225 kg hm ?2 (N3), 180 kg hm ?2 (N2) and 135 kg hm ?2 (N1). The results showed that farming measures and nitrogen application level had significant effects on wheat leaf area index, photosynthetic potential, SPAD value, and photosynthetic rate; irrigation level had significant effects on photosynthetic rate. During the whole growth periods, compared with CT, NT increased wheat leaf area index, photosynthetic potential, SPAD value, and photosynthetic rate by 14.5%-44.1%, 13.2%-16.3%, 7.4%-9.0%, and 14.5%-24.2%, respectively; Compared with I2, the photosynthetic rate of wheat I1 decreased by 6.5%-13.6%. Compared with N3, the leaf area index, photosynthetic potential, SPAD value, and photosynthetic rate of N1 decreased by 6.4%-13.6%, 7.5%-12.7%, 6.0%-10.2%, and 7.5%-17.5%, respectively. There was no significant difference between N2 and N3. Cultivation measures, nitrogen application level, and irrigation level all had significant effects on dry matter accumulation and grain yield in wheat. Compared with CT, NT increased by 13.4%-16.5% and 9.0%-13.4%; Compared with I2, I1 decreased by 6.5%-6.7% and 4.3%-7.4%; Compared with N3, the dry matter accumulation and grain yield of N1 decreased by 10.0%-11.9% and 12.6%-19.4%, respectively, and there was no significant difference between N2 and N3. Correlation matrix analysis showed that the combined water and nitrogen reduction of no-tillage maize mulching could delay the decrease of wheat SPAD value, prolonged the photosynthetic time, and increased the photosynthetic potential and photosynthetic rate of wheat to increase yield. Table and Figures | Reference | Related Articles | Metrics

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Effects of exogenous melatonin on morphology, photosynthetic physiology, and yield of spring soybean variety Suinong 26 under drought stress ZHANG Ming-Cong, HE Song-Yu, QIN Bin, WANG Meng-Xue, JIN Xi-Jun, REN Chun-Yuan, WU Yao-Kun, ZHANG Yu-Xian Acta Agronomica Sinica    2021, 47 (9): 1791-1805.   DOI: 10.3724/SP.J.1006.2021.04154 Abstract （275）   HTML （13）    PDF（pc） （923KB）（262）       Knowledge map    Save It is of great significance to study the mechanism of improving the drought resistance ability of soybean seedlings for the growth of soybean seedlings in Northeast China. This experiment was conducted using ‘Suinong 26’ as the experimental material with four treatments to investigate the physiological indexes and yield of soybean under drought stress, including the normal nutrient solution (CK), the drought stress treatment (D), the drought stress + foliar spraying melatonin treatment (LM), and the drought stress + irrigation melatonin treatment (RM). The results indicated that the gas exchange parameters, the dry matter accumulation of organ at seedling stage, the activities of antioxidant enzyme, and the content of soluble protein were increased under LM and RM compared with D. The net photosynthetic rate and stomatal conductance were significantly increased at V2 and V4 stages, and the transpiration rate and intercellular carbon dioxide concentration were significantly increased at V4 stage with P < 0.05; POD and CAT of RM were significantly increased at P < 0.05; the content of soluble protein was significantly increased after drought stress at V2 and V4 stages at P < 0.05. Compared with D, the yield of soybean with LM at V2 and V4 stages was increased by 24.2% and 19.1% at P < 0.05, RM increased by 38.6% and 56.3% at P < 0.05. Compared with LM, the yield of soybean with RM at V2 and V4 stages was increased by 11.6% and 31.3% at P < 0.05. These results revealed that the application of melatonin increased the yield of soybean under drought stress and the yield of soybean with irrigation melatonin treatment was higher than that of foliar spraying melatonin treatment. Table and Figures | Reference | Related Articles | Metrics

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Effects of interaction between calcium and nitrogen fertilizers on dry matter, nitrogen accumulation and distribution, and yield in peanut WANG Jian-Guo, ZHANG Jia-Lei, GUO Feng, TANG Zhao-Hui, YANG Sha, PENG Zhen-Ying, MENG Jing-Jing, CUI Li, LI Xin-Guo, WAN Shu-Bo Acta Agronomica Sinica    2021, 47 (9): 1666-1679.   DOI: 10.3724/SP.J.1006.2021.04186 Abstract （277）   HTML （12）    PDF（pc） （485KB）（260）       Knowledge map    Save The purpose of this study was to investigate the effects of calcium and nitrogen fertilizer on dry matter, nitrogen accumulation and distribution, and yield in peanut. A field experiment was conducted using Huayu 25 with two calcium (Ca) rates (0 and 600 kg hm-2), and five nitrogen (N) rates (0, 75, 150, 225, and 300 kg hm-2) in Jiyang (JY) and Yinmaquan (YMQ) in 2019. The results showed that compared with Ca0, the dry matter accumulation of peanuts under Ca600 treatment was significantly increased by 13.5% in the Jiyang, by 12.6% in Yinmaquant. Compared with N0, nitrogen fertilizer significantly promoted the accumulation of dry matter in peanut, and the N75, N150, N225, N300 treatments increased dry matter accumulation by 12.8%, 17.7%, 26.3%, 21.0% in Jiyang and 16.7%, 28.4%, 24.9%, 22.9% in Yinmaquan, respectively. The dynamic curve of peanut dry matter and nitrogen absorption accumulation conformed to the Logistic model, and the maximal nitrogen accumulation (Ym) was obtained under Ca600N225treatment in Jiyang and Ca600N150 treatment Yinmaquan. Compared to the average, the maximal speed of accumulation (Vm), the maximal biomass, duration of rapid accumulation (T), were increased at two plots by 12.4% and 10.6%, 14.9% and 13.7%, 2.3% and 3.1%, respectively. The starting date of rapid accumulation period (t1) was 7.5 days and 9.4 days earlier for nitrogen than for dry matter, indicated that the nutrient absorption of peanut was the premise of dry matter accumulation. The pod yield of peanut of Ca600N225 in Jiyang and Ca600N150 and Ca600N225 in Yinmaquan was higher than other treatments. Effects of interaction between calcium rates and nitrogen rates had a significant impact on peanut yield. Increasing calcium fertilizer application was an important way to improve nitrogen use efficiency, which increased pod number and 100-pod weight and promoted stably high yield in peanut. In this study, calcium fertilizer (600 kg hm-2) and nitrogen fertilizer (75 kg hm-2) were applied as the optimal fertilization scheme in the cultivation of less-fertilizer, stable-yield, and improved-efficiency treatment, while calcium fertilizer (600 kg hm-2) and nitrogen fertilizer (150-225 kg hm-2) as high-yield and high-efficiency treatment. Table and Figures | Reference | Related Articles | Metrics

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Effects of salinity stress on spikelets formation and grains filling in rice ( Oryza sativa L.) WEI Huan-He, ZHANG Xu-Bin, GE Jia-Lin, CHEN Xi, MENG Tian-Yao, YANG Yang, XIONG Fei, CHEN Ying-Long, DAI Qi-Gen Acta Agronomica Sinica    2021, 47 (12): 2471-2480.   DOI: 10.3724/SP.J.1006.2021.02083 Abstract （260）   HTML （20）    PDF（pc） （358KB）（259）       Knowledge map    Save This study was conducted to explore the effects of salinity stress on spikelets formation and grains filling in rice. To analyze the effects of salinity stress on the differentiation and degradation of spikelets, development of floral organs, and grain-filling characteristics in rice, conventional japonica rice Nanjing 9108 and Yandao 12 were used with three salinity treatments under pot-cultivation conditions, control (CK, 0 salt concentration), medium-salinity stress (MS, 0.15% salt concentration), and high-salinity stress (HS, 0.3% salt concentration). As a result, compared with the CK, (1) rice grain yield was decreased under salinity stress. The grain yield of Nanjing 9108 was decreased by 18.7% and 54.5%, and Yandao 12 was decreased by 24.3% and 58.6%, under MS and HS treatments, respectively. (2) the number of spikelets per panicle was decreased under salinity stress. The number of spikelets per panicle of Nanjing 9108 was 8.6% and 19.8%, and Yandao 12 was 8.0% and 25.9% lower than that of CK under MS and HS treatments, respectively. Besides, the filled-grain percentage and grain weight of Nanjing 9108 and Yandao 12 under MS and HS were also significantly lower than CK. (3) the number of differentiated and survived spikelets was decreased, while the number of retrograded spikelets and its rate was increased under salinity stress. Salinity stress reduced the differentiated and survived spikelets on the primary and secondary branches, while increased retrograded spikelets. The decline in the number of differentiated and survived spikelets on the secondary branches were higher than those of primary branches, and the similar observations were also for the increase in the number of retrograded spikelets. (4) the length, width, and volume of anther were decreased under salinity stress, and the similar trends were also observed for dehiscence rate of anther, pollen vigor, and the length and width of spikelets. Our results suggested that, salinity stress could inhibit the differentiation of rice spikelets and promote the degradation of spikelets, resulting in a significant decrease in the number of spikelets per panicle; it adversely affected the development of floral organs and reduced the fullness of grains, which significantly deteriorated the characteristics of grain plumpness. Table and Figures | Reference | Related Articles | Metrics

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Analysis of main quality index of corn harvesting with combine in China WANG Ke-Ru, LI Lu-Lu, GAO Shang, WANG Yi-Zhou, HUANG Zhao-Fu, XIE Rui-Zhi, MING Bo, HOU Peng, XUE Jun, ZHANG Guo-Qiang, HOU Liang-Yu, LI Shao-Kun Acta Agronomica Sinica    2021, 47 (12): 2440-2449.   DOI: 10.3724/SP.J.1006.2021.03046 Abstract （295）   HTML （21）    PDF（pc） （1541KB）（257）       Knowledge map    Save Mechanical harvest of corn grains is of major importance for China’s corn production. In this study, we used data from a total of 155 experimental sites to study mechanical grain harvest in 21 major corn producing provinces, cities, or autonomous regions in China from 2012 to 2019. Corn hybrids suitable for mechanical grain harvest were selected and field tests of mechanical harvest quality were carried out. A total of 865 corn varieties (hybrid combinations) were tested, and 8961 samples of mechanically harvested grain were obtained from 2987 tests. The harvested grains were assessed for grain quality to provide a basis for developing mechanical harvest corn in China. Results showed that, on the average, moisture content of harvested grain was 25.91%, grain breakage rate was 7.96%, impurity rate was 1.18%, and loss rate was 3.54%. Additionally, the ear loss accounted for 76.5% of the total harvest losses. Compared with the test data from 2012 to 2015, the quality of corn harvest in China had been significantly improved in recent years, with the average moisture content of harvested grains decreasing by an average of 0.78 percentage point every year and the average grain breakage rate decreasing by an average of 0.51 percent every year between 2015 and 2019. Compared with data of corn harvest of the United States between 2011 and 2019, the average moisture content of harvested corn from the present study was 9.5 percentage points higher, and the breakage rate and impurity rate were also significantly higher. Further analysis showed that both grain breakage rate and impurity rate were positively correlated with the grain moisture content. Additionally, grain breakage rate was the lowest when grain moisture content was 19.06%. Cross regarding different corn producing regions, the grain moisture content and grain breakage rate were the highest in the Huang-Huai-Hai summer corn region and lowest in the Northern China spring corn region, with medium values in the Northwestern China spring corn region and the Northeastern China spring corn region. The findings suggested that, in China, it was necessary to reduce the grain breakage rate, impurity rate, combine losses, and improve the harvest quality by breeding corn varieties with fast grain dehydration, low grain moisture content, and strong stalk stand ability at harvest stage, as well as by appropriately matching the dehydration characteristics of corn varieties with regional climate characteristics, improving the performance of harvesting machinery, and harvesting at the most appropriate time. Table and Figures | Reference | Related Articles | Metrics

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An growing-period indicator of maize cultivars for mechanical kernel harvest LI Lu-Lu, MING Bo, CHU Zhen-Dong, ZHANG Wan-Xu, GAO Shang, WANG Yi-Zhou, HOU Liang-Yu, ZHOU Xian-Lin, XIE Rui-Zhi, WANG Ke-Ru, HOU Peng, LI Shao-Kun Acta Agronomica Sinica    2021, 47 (11): 2199-2207.   DOI: 10.3724/SP.J.1006.2021.03049 Abstract （323）   HTML （19）    PDF（pc） （434KB）（256）       Knowledge map    Save The high kernel moisture of maize (Zea mays L.) at harvest stage limits the field-application of mechanical kernel harvesting. The breeding and selection of fast dry-down cultivars is the key to solve this problem. However, there is still a lack of such indicators for evaluating the kernel dry-down rate in China. To explore the indicators, the crop growth and the kernel dry-down of two cultivars, Xianyu 335 and Zhengdan 958, were investigated across various maize belts in China from 2014 to 2018. Between the two cultivars, there were significant varietal differences in thermal times (TT) at the stages of planting-maturity (P-M), planting-25% moisture (P-25%), and maturity-25% moisture (M-25%), respectively. The TTP-M on average were 3039°C d (2752-3249°C d) for Xianyu 335 and 3090°C d (2750-3546°C d) for Zhengdan 958, with a difference value of 51°C d, and the corresponding coefficient of variations (CV) of TTP-M were 4% and 6%, respectively. The TTP-25% on average was 3097°C d (2920-3392°C d) for Xianyu 335 and 3309°C d (2980-3613°C d) for Zhengdan 958, with a larger difference value of 212°C d, while their CV were 4% and 5%. In several, the TTM-25% for Xianyu 335 and Zhengdan 958 were 66°C d (0-287°C d) and 166°C d (36-338°C d) with the CV of 131% and 54%. On account of its better reflection of kernel dry-down rate among cultivars, the TTP-25% could be considered as the growing period indicator for the breeding and selection of cultivars fitting to present mechanical kernel harvesting. In addition, this indicator might vary with region, year, or planting date, the same field and year were recommended to ensure a consistent environmental condition for measuring it. Conclusively, a new indicator (TTP-25%) for breeding and selection of fast dry-down hybrids was proposed, which potentially prompting maize kernel harvesting in China. Table and Figures | Reference | Related Articles | Metrics