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    Physiological response of crop to elevated atmospheric carbon dioxide concentration: a review
    Yan-Sheng LI, Jian JIN, Xiao-Bing LIU
    Acta Agronomica Sinica    2020, 46 (12): 1819-1830.   DOI: 10.3724/SP.J.1006.2020.02027
    Abstract604)   HTML65)    PDF(pc) (1292KB)(841)       Save

    The increase of atmospheric concentration of carbon dioxide ([CO2]) has substantially had a huge impact on agricultural production. As the sole substrate for photosynthesis, the increase of atmospheric [CO2] stimulates the net photosynthetic rate, thus promoting the biomass accumulation and yield level in many crops. However, the ‘fertilization’ effect of the elevated atmospheric [CO2] on crop production is less than theoretical expectation, and elevated [CO2] increases the health risk due to the decline in grain quality. The relevant mechanism is still unclear. In this paper, we analyzed the effect of elevated [CO2] on crop photosynthesis system, reviewed various responses of key photosynthesis indicators, such as the leaf net photosynthetic rate, the intercellular [CO2] of leaves, maximum carboxylation rate of Rubisco (Vc, max), and the capacity of Rubp-regeneration (Jmax) in different crops, in response to the elevated atmospheric [CO2]. Based on the C-N metabolism of the whole plant, we summarized two prevailing hypotheses about the acclimation of photosynthetic capacity under elevated atmospheric [CO2], namely the source-sink regulation mechanism and N limitation mechanism, respectively. We summarized the influence of elevated [CO2] on the nutritional quality of the grain, such as the change in the protein, oil, mineral elements, and vitamin concentrations. Furthermore, we also reviewed the potential interactive effect of the elevated atmospheric temperature and [CO2] on crop growth. Finally, the main research directions of this field in the future are proposed. In summary, this review can provide theoretical reference for accurately assessing the changes in crop yield and quality under climate change conditions, maximizing the ‘fertilization’ effect of elevated [CO2], and mitigating the adverse effects of climate change on crop production.

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    Breeding of a novel clubroot disease-resistant Brassica napus variety Huayouza 62R
    LI Qian, Nadil Shah, ZHOU Yuan-Wei, HOU Zhao-Ke, GONG Jian-Fang, LIU Jue, SHANG Zheng-Wei, ZHANG Lei, ZHAN Zong-Xiang, CHANG Hai-Bin, FU Ting-Dong, PIAO Zhong-Yun, ZHANG Chun-Yu
    Acta Agronomica Sinica    2021, 47 (2): 210-223.   DOI: 10.3724/SP.J.1006.2021.04086
    Abstract532)   HTML27)    PDF(pc) (6984KB)(823)       Save

    The rapeseed clubroot disease incidence in China is about 0.67 million hectare, accounting for 10% of the canola production area, which become a serious threat for the safety of Brassica napus industry. Based on this, we used CR Shinki, a Chinese cabbage material containing CRb clubroot disease resistance locus, as the donor parent, and Pol.CMS restorer line Bing409, the parent of Brassica napus national approved varieties Huayouza 62, as the recipient parent, and the CRb resistance locus was introduced into Bing409 by breeding programs such as crossing, backcrossing, self-cross with the foreground and genetic background selection. In the BC3F2 generation, a new restorer line Bing409R with a genetic background close to Bing409 containing CRb resistance locus was obtained, and Huayouza 62R, the first rapeseed hybrid resistant to clubroot disease in China was successfully developed. The results were as follows: CRb disease resistance locus appeared as a dominant single-gene inheritance in B. napus background, and the genetic improvement of resistance to clubroot disease did not at the expense of yield and quality losses for new restorer line Bing409R and its hybrid Huayouza 62R. Bing409R and Huayouza 62R were showed immune-resistance to physiological races of Plasmodiophora brassicae in Sichuan, Hubei, and Anhui provinces in China. This study will provide valuable resources for the breeding of rapeseed in China, and supplemented important support to overcome the threat of rapeseed clubroot disease.

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    Effects of water saving and nitrogen reduction on soil nitrate nitrogen distribution, water and nitrogen use efficiencies of winter wheat
    LUO Wen-He, SHI Zu-Jiao, WANG Xu-Min, LI Jun, WANG Rui
    Acta Agronomica Sinica    2020, 46 (6): 924-936.   DOI: 10.3724/SP.J.1006.2020.91060
    Abstract707)   HTML25)    PDF(pc) (854KB)(697)       Save

    In order to solve the problems of excessive nitrogen input and irrigation water resources scarcity in current winter wheat production in Guanzhong Plain, winter wheat grain yield, water and nitrogen use efficiency, and nitrate nitrogen leaching were investigated to hopefully provide a theoretical basis for determining water-saving and nitrogen-reducing cultivation model. The two-factor split-plot field experiment (2017-2019) was conducted in Yangling, Shaanxi province, China, where the nitrogen application rates of N300 (300 kg hm -2), N225 (225 kg hm -2), N150 (150 kg hm -2), N75 (75 kg hm -2), N0 (0 kg hm -2, no nitrogen application) were assigned to the main plots, and the irrigation amount of W2 (1200 m 3 hm -2), W1 (600 m 3 hm -2), W0 (0, no irrigation) were assigned to the subplots. The amount of irrigation and nitrogen application had significant effects on wheat yield, water and nitrogen use efficiency, soil nitrate nitrogen content as well as its leaching loss. In the 2017-2018 and 2018-2019 wheat seasons, the irrigation treatments (W1 and W2) significantly increased the wheat yield by 14.88%-15.01% and 4.11-4.16 times, respectively, but the difference between them was not significant, while the risk of soil nitrate nitrogen leaching under irrigation of 600 m 3 hm -2 in overwintering period was significantly reduced. Under the irrigation of 600 m 3 hm -2in overwintering period, the yield was the highest in N150 treatment in 2017-2018, and in N225 treatment in 2018-2019, the N150 treatment had higher nitrogen use efficiency, and soil nitrate nitrogen leaching was also reduced by 15.87% and 10.20% compared with that of N225 treatment in 2017-2019. Therefore, N150 treatment (with nitrogen application rate of 150 kg hm -2) combined with W1 treatment (irrigated 600 m 3 hm -2in overwintering period) can improve the water and nitrogen utilization efficiencies and reduce the risk of nitrate nitrogen leaching, realizing the water-saving and nitrogen reduction production of winter wheat in Guanzhong Plain.

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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
    Abstract353)   HTML173)    PDF(pc) (12120KB)(658)       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.

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    Cloning and functional analysis of a drought tolerance-related gene IbNAC72 in sweet potato
    ZHANG Huan, YANG Nai-Ke, SHANG Li-Li, GAO Xiao-Ru, LIU Qing-Chang, ZHAI Hong, GAO Shao-Pei, HE Shao-Zhen
    Acta Agronomica Sinica    2020, 46 (11): 1649-1658.   DOI: 10.3724/SP.J.1006.2020.04051
    Abstract932)   HTML117)    PDF(pc) (4569KB)(649)       Save

    NAC (NAM/ATAF/CUC) is a plant-specific transcription factor family, which plays an important role in plant growth, development and stress responses. In this study, we cloned IbNAC72, a drought tolerance-related gene from sweet potato [Ipomoea batatas (L.) Lam.] variety Lizixiang by RACE method. The IbNAC72 cDNA of 1319 bp in length, had an open reading frame (ORF) of 1008 bp, and encoded a 335 amino acids polypeptide, with a molecular weight of 37.4 kD and an isoelectric point (pI) of 8.76. The genomic DNA of IbNAC72 gene was 1199 bp and was deduced to contain 3 exons and 2 introns. Sequence alignment and phylogenetic analysis revealed that IbNAC72 had a close relationship with the predicted protein products of Ipomoea nil. RT-qPCR analysis showed that IbNAC72 was expressed at the highest level in the leaves of sweet potato, and it was strongly induced by PEG-6000 and NaCl, respectively. IbNAC72 was transformed into tobacco via Agrobacterium-mediated transformation. Its overexpression significantly enhanced drought tolerance in the transgenic tobacco plants. Under drought stress, transgenic plants developed stronger root system; the SOD activity was significantly increased whereas the MDA content was significantly decreased in transgenic plants compared to those of wild type plants. This study showed that IbNAC72 gene was closely related to drought tolerance, providing a basis for in-depth study on the drought tolerance molecular mechanism of IbNAC72 in sweet potato.

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    Genome dominance and the breeding significance in Triticeae
    LIU Deng-Cai, ZHANG Lian-Quan, HAO Ming, HUANG Lin, NING Shun-Zong, YUAN Zhong-Wei, JIANG Bo, YAN Ze-Hong, WU Bi-Hua, ZHENG You-Liang
    Acta Agronomica Sinica    2020, 46 (10): 1465-1473.   DOI: 10.3724/SP.J.1006.2020.01022
    Abstract690)   HTML46)    PDF(pc) (4156KB)(627)       Save

    Triticeae tribe houses a number of allopolyploid species that harbor combinations of various genomes. The different genomes of an allopolyploid may have asymmetric contributions to morphological traits. For instance, the taxon traits of allopolyploids within genus Triticum is highly like those from the donor species of A-genome, termed this phenomenon as A-genome dominance. Because of genome dominance, the allopolyploids of Triticeae are grouped into different species clusters with A, D, U, or St as the pivotal (dominant) genome. Genome dominance may confer the advantages in evolution and adaptation. In breeding, it is an important factor to influence the development of novel allopolyploid crops and the design of wheat-alien chromosome translocations.

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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
    Abstract422)   HTML46)    PDF(pc) (959KB)(604)       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.

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    Functional characteristics of TaPYR1, an abscisic acid receptor family gene in mediating wheat tolerance to drought stress
    HAN Le,DU Ping-Ping,XIAO Kai
    Acta Agronomica Sinica    2020, 46 (6): 809-818.   DOI: 10.3724/SP.J.1006.2020.91067
    Abstract727)   HTML106)    PDF(pc) (2376KB)(603)       Save

    ABA receptors are involved in the mediation of ABA signaling transduction through interaction with abscisic acid (ABA) molecules induced by osmotic stresses and play critical roles in regulating the drought stress tolerance in plants. In this study, TaPYR1, an ABA family gene in wheat that was shown to be differentially expressed in our previous transcriptome analysis was used to analyze its molecular property, expression patterns under drought stress condition, and functions in mediating plant adaptation to drought stress. TaPYR1 shares high similarities to its plant counterparts at amino acid level. TaPYR1 protein contains the conserved domains specified by the plant PYR proteins and was targeted onto the plasma membrane after endoplasmic reticulum (ER) assortment. The expression of TaPYR1 was induced in both roots and leaves under drought, with the highest expression levels at 48 h of drought treatment. Transgene analysis on TaPYR1 was performed to assess the gene function in mediating plant drought tolerance. Compared with wild type (WT), the tobacco lines overexpressing TaPYR1 enhanced growth vigor and increased fresh and dry weight under drought stress. In addition, the transgenic lines with TaPYR1 overexpression also increased photosynthetic function, enhanced activities of cellular antioxidant enzymes, and elevated the contents of osmolytes (i.e., proline and soluble sugar) under drought condition. Our investigation suggests that TaPYR1 transcriptively responds to drought stress signaling and plays an important role in regulating plant drought adaptation by improving the associated physiological processes.

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    Review of biochar structure and physicochemical properties
    ZHANG Wei-Ming, XIU Li-Qun, WU Di, SUN Yuan-Yuan, GU Wen-Qi, ZHANG Hong-Gui, MENG Jun, CHEN Wen-Fu
    Acta Agronomica Sinica    2021, 47 (1): 1-18.   DOI: 10.3724/SP.J.1006.2021.02021
    Abstract774)   HTML36)    PDF(pc) (2839KB)(602)       Save

    As a new emerging technology, biochar and its applications have been rapidly developed in recent years. However, due to large differences in carbonization materials and processes, it is difficult to compare or even contrast the results of biochar application studies, thus hindering the development of biochar applications to some extent. For this reason, our paper focuses on the key factors restricted the function of biochar, namely, the structure as well as physical and chemical properties of biochar, and then systematically presents the main research advances in recent years from the following perspectives of biochar such as definition, formation, structure, elemental composition, and other main physical-chemical properties, and property controlling-technologies. The paper analyses and summarizes the common and differential characteristics of biochar structure and physical and chemical properties and clarifies the relevant basic perspectives, statuses, trends, and consensus on the structure and properties of biochar. The structure and fundamental physical and chemical properties of biochar are believed to be the most important factors affecting the roles, function, and effects of biochar. They also determine the application field, scope, amount, objective, and direction of biochar. Therefore, the modification technology or optimal regulation technique is the key to develop the efficacy advantage, potential and values of biochar. By further combining the research and application of biochar, the basic principles and development directions of biochar physicochemical property research in the future focusing on the physical and chemical properties of biochar are evaluated from cycle and sustainable development of resources and material perspectives. This paper aims to provide the basis and reference for the development of basic scientific science and application technology studies on biochar.

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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
    Abstract306)   HTML34)    PDF(pc) (4960KB)(598)       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.

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    Establishment of screening method for salt tolerant soybean at emergence stage and screening of tolerant germplasm
    LIU Xie-Xiang,CHANG Ru-Zhen,GUAN Rong-Xia,QIU Li-Juan
    Acta Agronomica Sinica    2020, 46 (01): 1-8.   DOI: 10.3724/SP.J.1006.2020.94062
    Abstract674)   HTML89)    PDF(pc) (3749KB)(575)       Save

    Salinity is an important factor affecting crop production. Screening salt tolerant soybean germplasm is of great significance for the utilization of salinized soil in major soybean production regions. In order to select salt tolerant soybean, a screening method was developed by using six soybean accessions, including Zhonghuang 35, Zhonghuang 39, Williams 82, Tiefeng 8, Peking, and NY27-38. Seeds were grown in vermiculite and treated with 0, 100, and 150 mmol L -1 NaCl solution. Seedling rate (SR), plant height (H), fresh weight of shoot and root (FWS and FWR), dry weight of shoot and root (DWS and DWR) were decreased significantly under 150 mmol L -1 NaCl treatment, with significant difference among varieties. Therefore, 150 mmol L -1 NaCl was suitable to identify salt tolerant soybean at emergence stage. The salt tolerance index (SI) based on the growth and development of seedlings and the salt tolerance coefficient (ST) were significantly correlated with the salt tolerance. The method using salt tolerance index is non-destructive and does not require planting control, which could save time and labor in salt tolerant germplasm identification. Twenty-seven soybean resources were screened, in which three were highly tolerant (grade 1) and seven tolerant (grade 2) at emergence stage. Among them, Yundou 101, Zheng 1311, Wansu 1015, and Tiefeng 8 also showed salt tolerance (grade 1) at seedling stage. In summary, an effective method for screening salt tolerant soybean at emergence stage was developed, with vermiculite as the substrate, 150 mmol L -1 NaCl as suitable treatment solution, and salt tolerance index as the indicator. Four soybean accessions were found to be salt tolerant at both emergence and seedling stages. This screening method will be useful for identification of salt tolerant soybean germplasm.

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    Response of rhizosphere bacterial community diversity to salt stress in peanut
    DAI Liang-Xiang, XU Yang, ZHANG Guan-Chu, SHI Xiao-Long, QIN Fei-Fei, DING Hong, ZHANG Zhi-Meng
    Acta Agronomica Sinica    2021, 47 (8): 1581-1592.   DOI: 10.3724/SP.J.1006.2021.04160
    Abstract321)   HTML8)    PDF(pc) (1106KB)(567)       Save

    To characterize the peanut rhizosphere bacteria community in response to salt stress, a pot experiment was performed with different salt concentrations. The peanut rhizosphere soils at flowering and mature stages were sampled to extract DNA for constructing bacterial 16S rRNA gene library, and then high-throughput sequencing was performed for sequencing and bioinformatics analysis. The results showed that Proteobacteria, Actinobacteria, Patescibacteria, Acidobacteria, and Chloroflexi were the dominant phyla, and the orders Saccharimonadales, Betaproteobacteria, Sphingomonadales, Gemmatimonadales, and Rhizobiales were dominated in the peanut rhizosphere soils. Comparisons of the bacterial community structure of peanuts revealed that the relative abundance of Proteobacteria dramatically increased, while that of Actinobacteria decreased in salt-treated soils, and the fluctuation increased with the increase of the salt concentration. Moreover, applying calcium fertilizer under salt stress increased the abundance of Betaproteobacteria, Gemmatimonadales, and Sphingomonadales, which were affected by salt stress, growth stages, and exogenous calcium application. Cluster analysis revealed that the dominant bacteria of soil groups with high salt concentration were similar and clustered together, while the soil samples of the same growth period were similar and clustered together according to the bacterial structure at the genus level under non-salt stress conditions. Bacterial community structure differed in the growth stages and soil salt concentrations, whereas the differences of soil groups with or without calcium application were relatively small. Function prediction analysis indicated that the sequences related to secondary metabolites, glycan biosynthesis and metabolism, and amino acid and lipid metabolism were enriched in high salt-treated soils. The functional groups increased significantly during the fast-growth period, low salt stress, and basal calcium fertilizer treatments, which may play an important role on the growth and stress response in peanut. This study of microbial communities could lay the foundation for future improvement of stress tolerance of peanuts via modification of the soil microbes.

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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
    Abstract537)   HTML80)    PDF(pc) (1301KB)(558)       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.

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    Screening and identification of salt-tolerant rice germplasm in whole growth period
    SUN Xian-Jun,JIANG Qi-Yan,HU Zheng,ZHANG Hui-Yuan,XU Chang-Bing,DI Yi-Huan,HAN Long-Zhi,ZHANG Hui
    Acta Agronomica Sinica    2019, 45 (11): 1656-1663.   DOI: 10.3724/SP.J.1006.2019.92012
    Abstract676)   HTML21)    PDF(pc) (1389KB)(543)       Save

    Five hundred and fifty rice germplasm collected from different regions at home and abroad were tested at 10 days after transplanting treated with various salt concentrations (0, 0.3%, and 0.5% salinity) during whole growth period, the various salt concentrations were obtained by watering different volumes of water and seawater. Six agronomic-related traits, including plant height, panicle number per plant, main panicle length, seed setting rate, yield per plant and heading date, were investigated under 0, 0.3% salinity treatments, and salt-tolerant phenotype was investigated under 0.5% salinity treatment. Under the salt treatment of 0.3% salinity during whole growth period, the plant height of 550 (100%) rice varieties decreased significantly; and there were significant difference in panicle number per plant of 124 (90 up, 34 down) rice varieties, main panicle length of 414 (405 down, 9 up) rice varieties, seed setting rate of 145 (84 down, 61 up) rice varieties, yield per plant of 375 (343 down, 32 up) rice varieties, while no significant difference in heading date. Principal component analysis showed that 77.25% variation was contributed by the three agronomic-related traits including main spike seed-setting rate, effective tiller number and yield per plant. One hundred and twenty-one salt-tolerant rice varieties with yield salt tolerance index ≥ 0.8 were obtained under 0.3% salinity treatment, 78 salt-tolerant rice varieties with salt tolerance phenotype of level 3 were screened under the durable 42 days salt treatment of 0.5% salinity. There were 25 rice varieties with both the yield salt tolerance index ≥ 0.8 under 0.3% salinity treatment and phenotype of level 3 under the durable 42 days salt treatment of 0.5% salinity. These salt-tolerant varieties can be used for cultivar innovation and the further study on mechanism of salinity tolerance.

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    CRISPR/Cas9-mediated editing of the thermo-sensitive genic male-sterile gene TMS5 in rice
    CHEN Ri-Rong,ZHOU Yan-Biao,WANG Dai-Jun,ZHAO Xin-Hui,TANG Xiao-Dan,XU Shi-Chong,TANG Qian-Ying,FU Xing-Xue,WANG Kai,LIU Xuan-Ming,YANG Yuan-Zhu
    Acta Agronomica Sinica    2020, 46 (8): 1157-1165.   DOI: 10.3724/SP.J.1006.2020.92059
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    Thermo-sensitive genic male-sterile (TGMS) gene tms5 is most widely used in the two-line hybrid breeding system in China. To develop novel rice thermo-sensitive male sterile lines, we knocked out the TMS5 genes of six elite japonica and four indica rice varieties by using CRISPR/Cas9 gene editing technology. By analyzing the critical sterility-inducing temperature (CIST) of the newly TGMS lines, it was found that the CIST of japonica TGMS lines ZG75S, CYGS, YG0618S, ZG07S, T0361S, and 7679S were between 28°C and 32°C, the CIST of indica TGMS lines 2537S, 6150S and 6379S were between 24°C and 28°C, and the CIST of indica TGMS line 1109S was lower than 23.5°C. These results indicated that the CIST of tms5 mutant from different genetic background materials was different. The TGMS lines with lower CIST could be obtained by knocking out the TMS5 from different genetic background materials. A hybrid rice combination 1109S/8048 had high quality and high yield. The yield of 1109S/8048 was 13.1% higher than that of Fengliangyou 4. The creation of the TGMS 1109S and the high-yield cross combination 1109S/8048 provides a new way for high-yield breeding.

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    Effects of increasing planting density and decreasing nitrogen rate on dry matter, nitrogen accumulation and distribution, and yield of cotton
    Shi-Hong WANG,Zhong-Xu YANG,Jia-Liang SHI,Hai-Tao LI,Xian-Liang SONG,Xue-Zhen SUN
    Acta Agronomica Sinica    2020, 46 (3): 395-407.   DOI: 10.3724/SP.J.1006.2020.94074
    Abstract598)   HTML9)    PDF(pc) (578KB)(534)       Save

    A field experiment was conducted using Liaomian 6 with the treatments of three plant densities (5.25×10 4, 6.75×10 4, and 8.25×10 4 plants hm -2), and five nitrogen rates (0, 105, 210, 315, and 420 kg hm -2) in 2016 and 2017. Compared with D5.25, D6.75, and D8.25 dry matter accumulation of cotton significantly increased by 17.6% and 28.7% in 2016, 12.6% and 20.9% in 2017, respectively. Compared with N0, N105, N210, N315, and N420 increased dry matter accumulation by 4.5%, 11.1%, 13.7%, 16.3% in 2016 and 3.6%, 13.5%, 15.3%, 19.8% in 2017, respectively. The dynamic curve of cotton dry matter and nitrogen absorption accumulation conformed to the Logistic model, and the maximal nitrogen accumulation (Ym) was obtained under D8.25 N420 treatment in 2016 and 2017. Compared to the average, the maximal biomass, duration of rapid accumulation (T), the maximal speed of accumulation (Vm) increased by 17.3% and 23.8%, 5.20% and 9.9%, 11.45% and 13.8%, respectively in two years. The starting date of rapid accumulation period (t1) was 4.1 d and 6.4 d earlier for nitrogen than for dry matter, indicating that the nutrient absorption of cotton was the premise of dry matter accumulation. The lint yield of D5.25N315, D6.75N210 and D6.75N105 in 2016 as well as D5.25N315 and D6.75N210 in 2017 was significantly higher than that of other treatments. The interaction effect of planting density and nitrogen application amount significantly affected cotton yield. Increasing planting density and reducing nitrogen application amount can obtain high yield. It is recommended for this region that the cotton planting density should be increased from 5.25×10 4 to 6.75×10 4 plants hm -2, and the amount of nitrogen application decreased from 300 kg hm -2 to 105 kg hm -2in the first year, and then to 210 kg hm -2 in the next year.

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    Interactive effects of sowing pattern and planting density on grain yield and nitrogen use efficiency in large spike wheat cultivar
    Fei-Na ZHENG,Jin-Peng CHU,Xiu ZHANG,Li-Wei FEI,Xing-Long DAI,Ming-Rong HE
    Acta Agronomica Sinica    2020, 46 (3): 423-431.   DOI: 10.3724/SP.J.1006.2020.91046
    Abstract530)   HTML7)    PDF(pc) (530KB)(502)       Save

    In order to find out the way to achieve further improvement in the grain yield (GY) and nitrogen use efficiency (NUE) of winter wheat, two sowing pattern (the wide range sowing and conventional drilling sowing) and seven planting densities (130×10 4, 200×10 4, 270×10 4, 340×10 4, 410×10 4, 480×10 4, and 550×10 4 plants hm -2) were designed during 2015-2016 and 2016-2017 growing seasons. Tainong 18, a winter wheat cultivar with larger spike and lower tillering capacity, was used to investigate the combined effects of sowing pattern and planting density on GY and NUE. Compared with the conventional drilling sowing, the wide range sowing with higher planting density effectively alleviated the negative effect of increasing spikes per unit area and nitrogen uptake efficiency (NUpE) on decreasing single spike weight and nitrogen utilization efficiency (NUtE), respectively. Concurrent improvement in GY and NUE was achieved by increasing the number of spikes per unit area and NUpE. The planting density resulting in the highest GY and NUE under wide range sowing conditions was 410×10 4 plants hm -2, which was significantly higher than that (340×10 4 plants hm -2) under conventional drilling sowing. Moreover, the increase percentage of GY and NUE under wide ranging sowing was also significantly higher than that under drilling sowing. In summary, it is feasible to further improve GY and NUE of large spike wheat cultivar through rational combination of wide range sowing with higher planting density. Under the condition of this experiment, the optimal combination measure for high GY and NUE was sowing width of 8-10 cm with plant density of 410×10 4 plants hm -2.

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    Research advance on calcium content in wheat grains
    LIU Yu-Xiu, HUANG Shu-Hua, WANG Jing-Lin, ZHANG Zheng-Mao
    Acta Agronomica Sinica    2021, 47 (2): 187-196.   DOI: 10.3724/SP.J.1006.2021.01045
    Abstract577)   HTML67)    PDF(pc) (418KB)(489)       Save

    Increasing the mineral content is becoming the important research direction and major target for crops breeding in the world. Calcium is an essential mineral element for human health and plays a pivotal role in skeletogenesis and metabolism. It is estimated that about 3.5 billion people was suffered from calcium deficiencies. Calcium deficiency has become a major international problem harming human health. The staple food is an optimal and safe way to mineral supplement. Wheat, one of the main food crops in China and even in the world, is the main source of food for 35%-40% of global population, a main source for human’s calcium intake as well as an important crop of mineral element biofortification. Improving the calcium content in wheat grains through genetic improvement is considered to be the most economical, effective and sustainable measure to solve the calcium deficiency, which has aroused great concern from international scholars. This paper summarized the recent advances in the study of calcium content in wheat grains, mainly including the genetic variation, affecting factors, the relationship with related traits and regulation mechanism of calcium content in grain. Furthermore, we also put forward the direction of future research on calcium-fortified wheat, which provides solutions for accelerating the effective calcium supplementation through staple food, promoting the healthy and nutritious dietary pattern, ensuring the food security to meet the transition from “quantitative” to “qualitative” demands, improving people’s health, and reducing economic losses caused by calcium deficiency.

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    Effect of integrated agronomic managements on leaf growth and endogenous hormone content of summer maize
    YU Ning-Ning,ZHANG Ji-Wang,REN Bai-Zhao,ZHAO Bin,LIU Peng
    Acta Agronomica Sinica    2020, 46 (6): 960-967.   DOI: 10.3724/SP.J.1006.2020.93050
    Abstract517)   HTML25)    PDF(pc) (622KB)(483)       Save

    The leaves are the main place of photosynthesis directly related to the nutritional status, dry matter accumulation and yield formation of maize plants. The experiment was conducted using summer maize hybrid Zhengdan 958 with treatments of T1: local conventional cultivation practices; T2: based on T1, increasing planting density, delaying harvesting time, decreasing fertilizer application, and changing fertilization time; T3: based on T2, further increasing planting density, and further increasing fertilizer rate; T4: based on T3, decreasing planting density and the amount of fertilizer; and nitrogen treatments of N0, N1, N2, and N3, with 0, 129.0, 184.5, and 300.0 kg N hm -2, respectively. The contents of IAA, ZR, and GA3 decreased and the content of ABA increased, resulting in the decreases of SPAD, leaf area index (LAI) and specific leaf mass, when nitrogen application was not enough. And the contents of IAA, ZR, and GA3 increased, and ABA content decreased, and LAI, SPAD and dry matter accumulation per plant increased significantly with increasing nitrogen application. Integrated agronomic management practices could regulate the content of endogenous hormones in leaves. In T4 treatment, IAA, ZR, and GA3 contents increased by 23.1%, 9.8%, and 14.7%, the ABA content decreased by 12.4%, resulting in a suitable LAI; SPAD and final dry matter accumulation per plant were by 4.2% and 12.6% higher, respectively, than those in T1 treatment. Integrated agronomic managements could coordinate endogenous hormone contents, increase leaf SPAD and specific leaf mass, and be beneficial to dry matter accumulation per plant under the condition of reducing nitrogen application combining with optimal agronomic managements, which might be one of the important reasons for increasing summer maize yield.

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    Mapping and genetic analysis of QTLs for Fusarium head blight resistance to disease spread in Yangmai 16
    HU Wen-Jing,ZHANG Yong,LU Cheng-Bin,WANG Feng-Ju,LIU Jin-Dong,JIANG Zheng-Ning,WANG Jin-Ping,ZHU Zhan-Wang,XU Xiao-Ting,HAO Yuan-Feng,HE Zhong-Hu,GAO De-Rong
    Acta Agronomica Sinica    2020, 46 (02): 157-165.   DOI: 10.3724/SP.J.1006.2020.91048
    Abstract772)   HTML77)    PDF(pc) (2398KB)(481)       Save

    Fusarium head blight (FHB) resistance of Yangmai wheat cultivars has been paid much attention, but the underlying genetic mechanism is unclear. In recent years, Yangmai 16 is a predominant wheat cultivar durably resistant to FHB in production. A population of 174 double haploid lines (DH) produced by crossing Yangmai 16 (YM16) with the susceptible cultivar Zhongmai 895 (ZM895) was evaluated for FHB response using point inoculation from 2017 to 2019. The DH population was genotyped with wheat 660K SNP array and a high-density genetic map was constructed. Six resistance QTLs were detected, and among them, five were from the resistant parent Yangmai 16 and one from Zhongmai 895. QFhb.yaas-4DS and QFhb.yaas-6AS were detected at least in two years, explaining 8.8% to 15.0% of the phenotypic variances, respectively. QFhb.yaas-2DL and QFhb.yaas-3BL were detected only in one year, accounting for 10.5% and 14.7% of the phenotypic variances. QFhb.yaas-5BL and QFhb.yaas-4BS were detected in one year, too, accounting for 6.4% and 8.3% of the phenotypic variances, respectively. Pyramiding of multiple resistant loci with large effects (>10%) is an effective approach to increase FHB resistance. The QTLs identified from Yangmai 16 in the present study will provide a starting point for genetic studies of other Yangmai cultivars, and the QTLs closely linked to markers will be useful for marker-assisted selection in wheat FHB improvement.

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    Genome-wide association studies of leaf orientation value in maize
    PENG Bo,ZHAO Xiao-Lei,WANG Yi,YUAN Wen-Ya,LI Chun-Hui,LI Yong-Xiang,ZHANG Deng-Feng,SHI Yun-Su,SONG Yan-Chun,WANG Tian-Yu,LI Yu
    Acta Agronomica Sinica    2020, 46 (6): 819-831.   DOI: 10.3724/SP.J.1006.2020.93063
    Abstract788)   HTML57)    PDF(pc) (2510KB)(474)       Save

    Leaf orientation value is a comprehensive index reflecting the two characteristics of “straight” and “vertical” of leaves. The varieties with high leaf orientation value have straight and not curved leaves, and small angle, which are conducive to the wind ventilation and light transmission for maize population. When the planting density is high, it is easier to obtain high yield than the expanded plant-type. It is of great significance for molecular design breeding of ideal plant type to clarify the genetic basis of leaf orientation value. In this study, 285 diverse lines genotyped by the MaizeSNP50 chip were evaluated for leaf orientation in 2017 and 2018. The genome-wide association analysis (GWAS) were used to identified the SNPs, which were significant association with leaf orientation values. The analysis of variance showed that the significant variations were observed for leaf orientation value of different inbred lines (P < 0.01). In the selection of the optimal model, it was found that the Q + K model was the most suitable for the leaf orientation association analysis in this study. A total of 15 loci (P < 4.05E-5) were detected by GWAS, including 27 SNPs, explaining 5.54%-8.73% of phenotypic variation, and 15 candidate genes were mined in two years. Among them, site 2 in 1.07 bin was an important site found in this study, and its candidate gene might be Zm00001d032050 encoding cyclin dependent protein kinase, which needed to be further confirmed by map-based cloning.

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    Effect of nitrogen application on yield and rice quality of mechanical transplanting high quality late rice
    TANG Jian,TANG Chuang,GUO Bao-Wei,ZHANG Cheng-Xin,ZHANG Zhen-Zhen,WANG Ke,ZHANG Hong-Cheng,CHEN Heng,SUN Ming-Zhu
    Acta Agronomica Sinica    2020, 46 (01): 117-130.   DOI: 10.3724/SP.J.1006.2020.92010
    Abstract569)   HTML26)    PDF(pc) (498KB)(471)       Save

    The experiment was conducted by using four high quality late rice varieties, including Taiyou 398, Huanghuazhan, Tianyouhuazhan, and Meixiangxinzhan under four nitrogen treatments of 0, 135, 180, and 255 kg hm -2 to select the optimum nitrogen application rate for the coordination of high quality and high yield. The appropriate increase of nitrogen application improved the yield of high quality rice, which reached maximum under the nitrogen treatment of 180 kg hm -2. When the nitrogen application was 180 kg hm -2, the indicators such as the brown rice rate, milled rice rate and head milled rice rate for all varieties reached maximum except for the head milled rice rate of Huanghuazhan. As more nitrogen was gradually applied, there were growing length-width ratio, protein content and gel consistency of double-season high-quality late rice while in contrast reduction in chalky grain percentage, chalkiness degree and amylose content, which also brought about a steady drop in peak viscosity, trough viscosity, breakdown, final viscosity while a rise in setback and pasting temperature. To sum up, the appropriate increase of nitrogen application can improve the processing quality, appearance quality, cooking and nutritional quality while deteriorate the RVA characteristics. The nitrogen application of 180 kg hm -2 facilitates a better coordination between quality and yield in high quality double-season late rice under mechanical transplanting.

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    Research advances on characteristics, damage and control measures of weedy rice
    CHEN Lei, JIN Man, ZHANG Wei-Le, WANG Cheng-Xu, WU Yong-Bin, WANG Zhi-Zhong, TANG Xiao-Yan
    Acta Agronomica Sinica    2020, 46 (7): 969-977.   DOI: 10.3724/SP.J.1006.2020.92064
    Abstract736)   HTML69)    PDF(pc) (3059KB)(470)       Save

    Weedy rice (Oryza sativa f. spontanea) presumably originated from rice but has weedy characteristics. It is one of the malignant weeds in rice field that decreases rice production and grain quality severely. In this study, the biological characteristics of weedy rice were described from morphology, shattering, dormancy and stress tolerance. The process of weedy rice origination from de-domestication of cultivated rice was summarized briefly. We also introduced the worldwide distribution of weedy rice as well as its non-uniform distribution in China with the most severe occurrence in middle-south area of Jiangsu province and Zhanjiang of Guangzhou province. In addition, we analyzed the agricultural damage on rice yield, rice quality and paddy field ecology environment by weedy rice. To control the occurrence and spread of weedy rice, we further proposed comprehensive measures, including prevention and controlling measures, reasonable cultivation system, and scientific use of chemical herbicides.

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    Effects of drought treatments at different growth stages on growth and the activity of osmotic adjustment in sweet potato [ Ipomoea batatas (L.) Lam.]
    ZHANG Hai-Yan, WANG Bao-Qing, FENG Xiang-Yang, LI Guang-Liang, XIE Bei-Tao, DONG Shun-Xu, DUAN Wen-Xue, ZHANG Li-Ming
    Acta Agronomica Sinica    2020, 46 (11): 1760-1770.   DOI: 10.3724/SP.J.1006.2020.04079
    Abstract581)   HTML29)    PDF(pc) (545KB)(468)       Save

    Field experiments were conducted using two sweet potato cultivars (Jishu 21, a drought-tolerant cultivar, and Jizishu 1, a drought-sensitive cultivar) with four water treatments to investigate the effects of drought treatments at different growth stages on growth and the activity of osmotic adjustment in sweet potato [Ipomoea batatas (L.) Lam.], including well-watered treatment during the whole growth period (WW, control), drought stress during the establishment stage (DS1), drought stress during the storage root initial stage (DS2), and drought stress during the storage root bulking stage (DS3). Drought stress resulted in significant decrease of fresh weight of storage roots in sweet potato. Compared with drought stress in different periods, drought stress during the establishment stage (DS1) decreased the fresh weight most. Compared between cultivars, drought-sensitive cultivar decreased the fresh weight most. The average in three years, compared with the control, the fresh weight of drought-tolerant cultivar (Jishu 21) and drought-sensitive cultivar (Jizishu 1) decreased 28.59% and 38.77% in DS1 treatment, respectively, while 25.20% and 33.50% in DS2 treatment, respectively and 14.55% and 19.56% in DS3 treatment, respectively. Drought stress resulted in significant decrease of biomass of storage roots in sweet potato. One hundred days after planting, compared with the control, the biomass of aboveground part of Jishu 21 in DS1, DS2, and DS3 decreased 32.68%, 20.79%, and 11.72%, respectively, while Jizishu 1 decreased 46.45%, 31.89%, and 18.43%, respectively. The biomass of underground part of Jishu 21 in DS1, DS2, and DS3 decreased 37.69%, 25.86%, and 10.67%, respectively, while Jizishu 1 decreased 54.34%, 33.48%, and 14.20%, respectively. Under drought stress, the relative water content of functional leaves decreased, and the content of soluble sugar, soluble protein, free amino acid and proline in functional leaves, fibrous roots and storage roots increased. The earlier the application of drought stress, the greater the decrease or increase. The effects of drought stress applied at early stages on osmotic adjustment could not be effectively recovered after re-watering, while the osmotic adjustment could be recovered to the control level after re-watering when drought stress was applied at later stage.

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    Effect of planting density on light interception within canopy and grain yield of different plant types of maize
    Yan-Wen BAI,Yong-Hong YANG,Ya-Li ZHU,Hong-Jie LI,Ji-Quan XUE,Ren-He ZHANG
    Acta Agronomica Sinica    2019, 45 (12): 1868-1879.   DOI: 10.3724/SP.J.1006.2019.93011
    Abstract597)   HTML35)    PDF(pc) (976KB)(466)       Save

    The objective of this study was to clarify the relationship between light interception in canopy and dry matter production and grain yield in different plant types of maize. The response of morphological characteristics, canopy light distribution, grain filling parameters and dry matter accumulation were studied using three different maize hybrids Shaandan 609 (SD609, compact), Qinlong 14 (QL14, semi-compact), and Shaandan 8806 (SD8806, flat) with four plant densities (4.5×10 4, 6.0×10 4, 7.5×10 4, and 9.0×10 4plants hm -2) in the field from 2016 to 2017. The average yields of SD609, QL14, and SD8806 were 12,176, 9624, and 8533 kg hm -2, respectively, within two years, reaching high yields under 9.0×10 4, 7.5×10 4, and 6×10 4 plants hm -2, with the yield increase of 26.9%, 20.4%, and 19.7% compared with those under 4.5×10 4 plants hm -2, respectively. With the increase of plant density, leaf area decreased, but LAI and leaf orientation value increased. The middle leaves of SD609 were more upright and larger than those of QL14 under 9×10 4 plants hm -2. With increasing plant density, Dmax (days to the maximum grain-filling rate), Wmax (kernel weight at the maximum grain filling rate), Gmax (maximum grain-filling rate), Gave (average grain-filling rate) and P (active filling period) decreased, the Dmax for SD609 was 1.4 days and 3.0 days earlier than that of QL14 and SD8806, and the Wmax and P were higher than those of SD636 (0.3 g and 3.3 d) and SD8806 (1.1 g and 5.4 d), respectively. The dry matter accumulation after silking and the contribution of dry matter transportation to grain yield increased and then decreased with the increase of plant density, the accumulation, transportation and contribution to grain of dry matter after anthesis were higher in SD609 than QL14 (5.1%, 36.0%, 33.5%) and SD8806 (26.6%, 46.7%, 59.1%). The light interception in the ear canopy was significantly correlated with yield (r = 0.631, P < 0.05), the dry matter accumulation after silking (r = 0.661) and average grain filling rate (r = 0.859) at P < 0.01. Thus, compared with QL14 and SD8806, SD609 could regulate the mid and upper leaves more vertical under close planting, improve the light distribution in the mid and lower canopy, maintain a higher area of green leaves, delay the senescence of canopy leaves, increase dry matter accumulation after anthesis and grain filling rate, so obtain a higher grain yield.

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    Characteristics of post-anthesis carbon and nitrogen accumulation and translocation in maize cultivars with different low nitrogen tolerance
    WU Ya-Wei, PU Wei, ZHAO Bo, WEI Gui, KONG Fan-Lei, YUAN Ji-Chao
    Acta Agronomica Sinica    2021, 47 (5): 915-928.   DOI: 10.3724/SP.J.1006.2021.03033
    Abstract442)   HTML18)    PDF(pc) (1959KB)(462)       Save

    To understand the suitable amount of nitrogen (N) application and the potential of increasing yield and improve efficiency for the maize cultivars with different low N tolerance. The experiment was setting from 2017 to 2019, the low-N tolerant cultivar ‘Zhenghong 311 (ZH311)’ and the low-N sensitive cultivar ‘Xianyu 508 (XY508)’ were selected and four N application rates (0 kg hm-2, 150 kg hm-2, 300 kg hm-2, and 450 kg hm-2) were set to investigate the effects of N level on carbon (C) and N accumulation and translocation in the later growth stage of different maize cultivars. The results showed that in low N environment, maize increased the C and N translocations of pre-silking to the grain to ensure the yield. Increasing the N fertilizer applications could improve the contribution rates of dry matter and carbohydrate to grain yield. Compared with XY508, ZH311 had higher accumulations of plant dry matter, N and non-structural carbohydrate (NSC) of pre- and post-silking, and higher contribution rates of dry matter, N and accumulations to grain yield of post-silking, so it had higher grain yield. There was no significant difference between cultivars in the rate of dry matter, N and NSC translocation of pre-silking. In the face of low N stress, ZH 311 not only ensured the sufficient C and N translocations of pre-silking to the grain, but also maintained a higher capacity of assimilate accumulation to affect the yield formation.

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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
    Abstract392)   HTML56)    PDF(pc) (5135KB)(456)       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.

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    Seedling root characteristics and drought resistance of wheat in Shanxi province
    ZHAO Jia-Jia, QIAO Ling, WU Bang-Bang, GE Chuan, QIAO Lin-Yi, ZHANG Shu-Wei, YAN Su-Xian, ZHENG Xing-Wei, ZHENG Jun
    Acta Agronomica Sinica    2021, 47 (4): 714-727.   DOI: 10.3724/SP.J.1006.2021.01048
    Abstract474)   HTML21)    PDF(pc) (1008KB)(453)       Save

    Wheat root morphology at the seedling stage is the basis of root distribution at the adult stage. It is closely related to stress resistance and yield. A comprehensive understanding of the root system characteristics at seedling stage and drought resistance is of great significance for the excellent germplasm utilization and early screening of drought resistance. Using 239 wheat varieties (lines) from Shanxi province, the root traits at seedling stage and their response to water stress were evaluated. The results showed that under normal growth, Shanxi wheat had a great variation in root traits at seedling stage, with the greatest variation in landraces. The maximum root length (MRL) tended to decrease slightly with the years, while other root traits were first increased and then decreased. There were differences among the root traits in response to water stress. The total root length (TRL) is the most sensitive to water, followed by root surface area (RSA), root volume (RV) and root biomass. The maximum root length (MRL) and the average number of roots (RN) were insensitive. The drought resistance of seedling roots showed a trend of decreasing first and then increasing with the years. Landraces and varieties released from 1970 to 1979 had moderately resistance to water stress, varieties released from 1980 to 1999 had lower drought resistance, and varieties released after 2000 had the better resistance, of which the dryland varieties were the best resistance. Correlation analysis of the seedling root characteristics and yield related traits suggested that the maximum root length, total root length, root volume and root biomass were significantly positively correlated with 1000-kernel weight and yield under rain-fed conditions, and the maximum root length and root biomass were also significantly positively correlated with adult plant drought resistance. The present study suggests that the maximum root length and root biomass at the seedling stage can be used as early generation selection parameters for drought resistance and yield in dryland breeding in semi-arid areas.

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    Difference of physiological characteristics of grain weight at various kernel positions in wheat spikelets
    LI Yan-Xia,YANG Wei-Bing,YIN Yan-Ping,ZHENG Meng-Jing,CHEN Jin,YANG Dong-Qing,LUO Yong-Li,PANG Dang-Wei,LI Yong,WANG Zhen-Lin
    Acta Agronomica Sinica    2019, 45 (11): 1715-1724.   DOI: 10.3724/SP.J.1006.2019.91004
    Abstract478)   HTML20)    PDF(pc) (1605KB)(450)       Save

    The object of the experiment was to explore the main physiological mechanism of heterogeneous development of grains located at the various kernel positions in wheat spikelets, further to reveal the factors restricting grain filling of inferior grains located on the distal kernel positions. Two varieties with different spike sizes of winter wheat (a large-spike cultivar Tainong 18 and a multiple-spike cultivar Shannong 20) were used to as the experimental materials. We have studied the dynamic changes of concentrations of endogenous hormones, soluble sugar and total nitrogen in grains located at different kernel positions in wheat spikelets during grain-filling period, and the microstructure of vascular bundle junction on kernel handle and kernel weight. Correlation analysis showed that the grain filling rate was significantly correlated with the contents of GA and IAA in grains. Higher GA and IAA contents in proximal kernels could make the conversion from sucrose to starch start earlier, the seed differentiate rapidly and the grain-filling rate higher, which is the physiological mechanism of the higher weight of proximal kernel in wheat spikelets. The micrograph showed that the cross-sectional area of vascular bundle of seed stalk on proximal kernels at the early stage of grain-filling period was significantly larger than that of distal kernels, and the microcosmic space was small and orderly, which is conducive to the transport of assimilates and physiological active substances, showing an anatomical basis for the rapid increase of seed weight and higher grain-filling rate in the proximal kernels of spikelets.

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    Genome-wide association study of nitrogen use efficiency related traits in common wheat ( Triticum aestivum L.)
    JIN Yi-Rong, LIU Jin-Dong, LIU Cai-Yun, JIA De-Xin, LIU Peng, WANG Ya-Mei
    Acta Agronomica Sinica    2021, 47 (3): 394-404.   DOI: 10.3724/SP.J.1006.2021.01024
    Abstract438)   HTML30)    PDF(pc) (3110KB)(446)       Save

    Nitrogen application plays an important role in plant growth and development. Exploring genetic loci related to nitrogen use efficiency is of great significance for improving wheat yield and reducing environmental pollution. Root system architecture (RSA) determined the composition of plant root system, and significantly affected by nitrogen level. Under different nitrogen levels (deficiency and normal), 160 winter wheat accessions from the Huanghuai valley and Northern winter wheat region were counted for their root architecture-related traits (total root length, total root surface area, total root volume, average root diameter, and root tip number). Genotype was analyzed using 660K SNP (single nucleotide polymorphism) data. Genome-wide association study (GWAS) was employed to identify the relevant loci for nitrogen use efficiency. A total of 34 associated loci were detected, which explained 6.9%-15.4% of the phenotypic variation. These loci distributed on all chromosomes and mainly centered on chromosomes 1A, 2B, 3B, 5B, 6A, 6B, and 7A, respectively. Among the loci detected in this study, 11 loci overlapped or were close to the reported ones, while the other 23 might be novel loci. In addition, we explored a candidate gene encoding the E3 ubiquitin ligase. This study is of great significance for understanding the genetic mechanism of nitrogen utilization and breeding high-yield wheat varieties.

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    Genetic diversity of phenotypic traits in 257 Jerusalem artichoke accessions
    Meng-Liang ZHAO,Li-Hui WANG,Yan-Jing REN,Xue-Mei SUN,Zhi-Qiang HOU,Shi-Peng YANG,Li LI,Qi-Wen ZHONG
    Acta Agronomica Sinica    2020, 46 (5): 712-724.   DOI: 10.3724/SP.J.1006.2020.94098
    Abstract651)   HTML13)    PDF(pc) (450KB)(442)       Save

    In order to fully understand and effectively utilize the genetic diversity of Jerusalem artichoke accessions in China. 257 Jerusalem artichoke accessions were analyzed. Among them, 12 quantitative traits had 6%-50% of the coefficient of variation, with a mean of 24.75%, which was the highest in tuber weight per plant (50%) and the smallest in growth period (6%). The diversity index (H') of these 12 traits was 1.24-1.53, with a mean of 1.44, which was the highest in tuber number per plant (1.53) and the lowest in leaf width (1.24). The diversity index of the eight quality traits was 0.85-1.08, with a mean of 0.98, which was the highest in tuber habit and the lowest in tuber uniformity, showing rich genetic diversity in most traits. The subordinate function of 257 Jerusalem artichoke accessions was 0.12-0.58, in which the highest was in JA1095 (0.58) with the obvious advantages of flower number and tuber weight per plant. The correlation analysis of 12 quantitative traits indicated that stem diameter, leaf length, flower and disk size could be used as the main target traits for high yield Jerusalem artichoke varieties breeding in the future. The results of principal component analysis showed that the cumulative contribution rate of the seven principal component factors was 66.794%. Among them, the number of flowers, the tuber number per plant, the number of tuber hairs and the smoothness of tuber epidermis were the main factors contributing to the phenotypic difference of Jerusalem artichoke. By cluster analysis, 257 accessions materials were divided into five categories based on 20 traits,among them class I and class II accounted for 85% of the total germplasm resources. This results can provide an important reference for the utilization of Jerusalem artichoke accessions and variety breeding.

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    Genome-wide association study of ear cob diameter in maize
    MA Juan, CAO Yan-Yong, LI Hui-Yong
    Acta Agronomica Sinica    2021, 47 (7): 1228-1238.   DOI: 10.3724/SP.J.1006.2021.03048
    Abstract394)   HTML23)    PDF(pc) (8297KB)(441)       Save

    Maize ear cob diameter is an important trait impacting the yield of grain and cob, and the analysis of its genetic mechanism will provide a guidance for high-yield breeding. In this study, the genotypes of 309 inbred lines were identified by genotyping-by-sequencing technology. FarmCPU (fixed and random model circulating probability unification), MLMM (multiple loci mixed linear model), and CMLM (compressed mixed linear model) were used to identify significant single nucleotide polymorphisms (SNP) for ear cob diameter of Yuanyang of Henan province, Dancheng of Henan province, Yucheng of Henan province, Sanya of Hainan province in 2017 and 2019, and best linear unbiased estimate environment. A total of 12 significant SNP for ear cob diameter were detected at P < 8.60E-07. S4_29277313 was detected from Yuanyang in 2017 using FarmCPU and MLMM. The phenotypic variance explained of S1_29006330, S2_170889116, S2_2046026464, and S4_83821463 ranged from 10.23% to 14.17%, and were considered major-effect SNP. In addition, S1_29006330 was mapped in the interval of known QTL for ear cob diameter. A total of 17 candidate genes were identified. Among them, WAKL14 (wall-associated receptor kinase-like 14), transcription factor ZIM35 (zinc-finger protein expressed in inflorescence meristem 35), HMGA (HMG-Y-related protein A), histone-lysine N-methyltransferase ATX4 (Arabidopsis trithorax 4), and XTH32 (xyloglucan endotransglucosylase/hydrolase protein 32) might be important genes for ear cob diameter. The identification of four major-effect SNP and five candidate genes can provide an information for molecular marker-assisted breeding, fine mapping, and gene cloning.

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    Identification of co-expressed modules of cotton genes responding to Verticillium dahliae infection by WGCNA
    Ming-Chuan FU,Hao LI,Yi-Zhen CHEN,Zhan-Ji LIU,Ren-Zhong LIU,Li-Guo WANG
    Acta Agronomica Sinica    2020, 46 (5): 668-679.   DOI: 10.3724/SP.J.1006.2020.94124
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    Weighted gene co-expression network analysis (WGCNA) is a classic systematic biological method, which can be used to identify co-expressed modules, investigate relationships between modules and specific traits, and screen hub genes in the networks. Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, can cause severe fibre quality reduction and yield loss of cotton. Studying on cotton genes and molecular mechanisms related to defense responses against V. dahliae can shed light on cotton breeding. In this study, 21 transcriptome data of Gossypium barbadense seedling roots infected by V. dahliae were used to investigate differentially expressed genes (DEGs). By filtering out the genes with low variation, 35,647 genes were selected for WGCNA. In total, 22,850 DEGs were identified under V. dahliae infection, with 4685 in common at all inoculated time points. Co-expression network analysis identified 18 modules, in which five modules significantly associated with V. dahliae infection (black, mediumpurple3, darkolivegreen, plum3 positively correlated with the 2 h, 6 h, 48 h, and 72 h inoculated time points, respectively; mediumpurple2 negatively correlated with the 2 h inoculated time point). GO and KEGG enrichment analysis were performed on these five specific modules, which could be enriched in GO terms and metabolic pathways, such as cellular response to stimulus, calcium ion binding and flavonoid biosynthesis. The hub genes were screened by calculating gene connectivity in the corresponding networks, and they may play important roles in the resistance against biotic/abiotic stresses. In summary, by WGCNA, a few defense-related co-expressed modules and hub genes were identified. The results of this study would be beneficial for further understanding of the molecular mechanisms of pathogen resistance in cotton, and provide new gene resources for cotton breeding in the future.

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    Development and identification of transgenic rapeseed with a novel gene for glyphosate resistance
    LI Jie-Hua, DUAN Qun, SHI Ming-Tao, WU Lu-Mei, LIU Han, LIN Yong-Jun, WU Gao-Bing, FAN Chu-Chuan, ZHOU Yong-Ming
    Acta Agronomica Sinica    2021, 47 (5): 789-798.   DOI: 10.3724/SP.J.1006.2021.04169
    Abstract455)   HTML34)    PDF(pc) (11274KB)(428)       Save

    Glyphosate is the most widely used broad-spectrum herbicide in the world. However, at present there is no glyphosate-tolerant rapeseed variety with independent intellectual property rights in China. In the study, a novel glyphosate-resistant genes I. variabilis EPSPS was transferred to the Brassica napus pure line J9707 via the Agrobacterium tumefaciens-mediated hypocotyl method, and 126 T0-positive transgenic plants with 97.0% positive rate were generated. The T-DNA insertion with a single copy (44.8%) is dominant. The insertion locations of T-DNA in the lines of EPS-2, EPS-6, and EPS-7 were identified by inverse PCR method. The stability of the T-DNA insertion in these lines were further confirmed by insertion-specific PCR in their T0 to T3 plants. The gene expression analysis revealed that the I. variabilis EPSPS gene and its protein was stably expressed in different generations of transgenic lines in RNA and protein levels. Treatments with different doses of glyphosate indicated that the lines of EPS-1, EPS-2, EPS-5, EPS-6, and EPS-7 could tolerate four times of the recommended dose of glyphosate in production. Thus, the novel glyphosate-tolerant rapeseed lines generated in the present study will lay the foundation for the herbicide- tolerance rapeseed breeding in China.

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    Characteristics of yield components and population quality in high-nitrogen- utilization wheat cultivars
    DING Yong-Gang,LI Fu-Jian,WANG Ya-Hua,TANG Xiao-Qing,DU Tong-Qing,ZHU Min,LI Chun-Yan,ZHU Xin-Kai,DING Jin-Feng,GUO Wen-Shan
    Acta Agronomica Sinica    2020, 46 (4): 544-556.   DOI: 10.3724/SP.J.1006.2020.91041
    Abstract385)   HTML26)    PDF(pc) (721KB)(418)       Save

    In the rice-wheat rotation system, 24 and 23 wheat cultivars were separately planted in Yangzhou and Suining of Jiangsu province in 2016-2017 and 2017-2018. According to nitrogen utilization rate (NUR), these cultivars were clustered into three groups, i.e., NUR-H (NUR ≥ 50%), NUR-M (NUR 40%-50%), and NUR-L (NUR ≤ 40%), to identify the differences in grain yield, yield components, and population quality, which would provide a reference for cultivar selection for high-yield and high-efficiency in wheat production. Yangmai 25 and Ningmai 21 in Yangzhou and Huaimai 35 in Suining showed NUR-H phenotypes in consecutive two years. Grain yield of the NUR-H cultivars was more than 6500 kg hm -2 in Yangzhou and 7000 kg hm -2 in Suining, which were significantly higher than those of NUR-M and NUR-L groups. NUR-H group had more spikes, and it grains per spike and 1000-grain weight were not significantly different from those of the other groups. Grain yield and spikes number were significantly positively correlated with NUR among different cultivars. More stem and tiller number, higher percentage of fertile tillers and higher leaf area index (LAI) at the milk-ripening stage were shown in the NUR-H group. A higher dry matter accumulation at stages of booting, anthesis, and maturity, after anthesis, and in the vegetative organs at maturity were found in the NUR-H group. However, there were no differences in dry matter remobilization and harvest index among different cultivars. Number of stems and tillers at booting and anthesis, LAI at the milk-ripe stage, and dry matter accumulation at each stage after anthesis, and in the vegetative organs at maturity were significantly positively correlated with NUR in the all cultivar in two sites. A vigorous tillering capacity at the early growing phase and a higher LAI and photosynthetic production at the late growth stages could be observed in NUR-H cultivars, resulting in more photosynthate for grain-filling. Furthermore, the critical parameters of cultivar screening for high-yield and high-efficiency in wheat following rice were proposed, that is 16,000-20,000 kg hm -2 dry matter accumulation at maturity and 4100-6700 kg hm -2 dry matter accumulation after anthesis.

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    Comparative proteomic analysis of two wheat genotypes with contrasting grain softness index
    LIU Pei-Xun,MA Xiao-Fei,WAN Hong-Shen,ZHENG Jian-Min,LUO Jiang-Tao,PU Zong-Jun
    Acta Agronomica Sinica    2020, 46 (8): 1275-1282.   DOI: 10.3724/SP.J.1006.2020.91068
    Abstract465)   HTML22)    PDF(pc) (636KB)(413)       Save

    Wheat is the crop most widely grown in the world and provides the daily protein and 20% food calories for 4.5 billion people. It is crucial to understand the genetic basis of grain hardness for improving wheat quality. In order to explore the molecular basis of the formation of wheat grain hardness, two wheat cultivars Chuanmai 66 and Shumai 969 with significant hardness difference in southwest wheat region were selected to analyze the proteins differential expression by TMT quantitative proteomics (tandem mass tags) and bioinformatic methods of function and pathway enrichment analysis. A total of 6020 effective proteins were identified and quantified, including 113 differentially expressed proteins (DEPs), of which 69 were up-regulated and 44 were down-regulated in soft wheat Chuanmai 66. These DEPs were enriched into 65 GO terms, including a biological process term, a cellular component term and six molecular function terms at extremely significant level. Based on the enrichment analysis, we suggested that nutrient reservoir activity proteins, enzyme inhibitor proteins and glutathione metabolism proteins might participate in the formation of wheat grain hardness, and grain hardness related proteins might mainly distribute in the extracellular region of cells and had defensive function. According to the phylogenetic analysis, it was inferred that puroindolines and its homologous proteins might be as not only wheat grain storage proteins, but also enzyme inhibitors regulating grain development. This study provides a basis for further exploring the genetic mechanism of wheat grain hardness.

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    Mapping of an incomplete dominant gene controlling multifoliolate leaf by BSA-Seq in soybean ( Glycine max L.)
    ZHANG Zhi-Hao, WANG Jun, LIU Zhang-Xiong, QIU Li-Juan
    Acta Agronomica Sinica    2020, 46 (12): 1839-1849.   DOI: 10.3724/SP.J.1006.2020.04075
    Abstract360)   HTML23)    PDF(pc) (3196KB)(412)       Save

    The leaves of cultivated soybean (Glycine max L.) are comprising of three leaflets in general, but there are also individual varieties or mutants which have a high frequency of compound leaves with 4-7 leaflets, named multifoliolate leaves. Compound leaf formation enhances the plant's ability to adapt to the external environment. Study of related genes to multifoliolate leaves might contribute to the improvement yield level of and soybean agronomic traits. In this study, a multifoliolate leaf mutant Zhonghuang 622 was identified from the mutant library of soybean cultivar Zhongpin 661, which had 4-9 leaflets in each compound leaf. The compound leaf phenotypes of F2 and F2:3 population from a cross between Zhongpin 661 and Zhonghuang 622 were investigated in Beijing and Hainan, respectively. Analysis of phenotypic data from F2 and F2:3 population revealed that the multifoliolate leaf trait was controlled by an incomplete dominant gene. BSA-Seq method was used for gene mapping. The two bulks of normal trifoliate and multifoliolate individuals in F2 population were constructed and sequenced for an average depth of 32.75×, which covered 99.22% genome compared to the reference genome. Through correlation analysis of mixed pool sequencing results by ED method, two regions were located on chromosome 11, with a total length of 5.29 Mb and a total length of 1103 genes. Three regions were identified on chromosome 11 at confidence of 0.99, with a total length of 3.42 Mb and a total of 701 genes by the association analysis of SNP-index method. There were 690 genes located simultaneously and six SNP genes between parents by the two association analysis methods. These results lay the foundation for map-based cloning of the genes related to compound leaf development.

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    Efficient screening system of effective sgRNA for cotton CRISPR/Cas9 gene editing
    ZHOU Guan-Tong, LEI Jian-Feng, DAI Pei-Hong, LIU Chao, LI Yue, LIU Xiao-Dong
    Acta Agronomica Sinica    2021, 47 (3): 427-437.   DOI: 10.3724/SP.J.1006.2021.04178
    Abstract397)   HTML10)    PDF(pc) (4263KB)(412)       Save

    Single guide RNA (sgRNA) is one of the important elements of the CRISPR/Cas9 genome editing technology system. However, studies have shown that many sgRNAs cannot work effectively. It is worth screening to verify the effectiveness of multiple design candidate sgRNAs. Instantaneous transformation of protoplasts or leaves with complete editing vectors were used to verification of the effectiveness of sgRNA in the early stage. These methods are time-consuming and laborious, and the success rate is not high, especially for cotton with low efficiency of the protoplasmic system. In this study, target sequences were designed for GhMAPKKK2 and GhAE genes, and two vectors of GhU6-5P::MAPKKK2-sgRNA-1300, GhU6-5P::AE-sgRNA-1300 which transcibed only sgRNA were constructed and injected YZ-1 Cas9 transgenic cotton plant leaves through Agrobacterium; meanwhile, two corresponding complete CRISPR/Cas9 genome editing vectors of GhU6-5P::MAPKKK2-sgRNA-Cas9 and GhU6-5P::AE-sgRNA-Cas9 were constructed and injected YZ-1 wild-type cotton leaves with Agrobacterium. In addition, target sequences were designed for GhPDS, GhCLA1, GhMAPKKK2, and GhAE genes, respectively, and GhU6-5P-2::PDS-sgRNA- CLCrVA, GhU6-5P-2::CLA1-sgRNA-CLCrVA, GhU6-5P-2::MAPKKK2-sgRNA-CLCrVA and GhU6-5P-2::AE-sgRNA-CLCrVA virus delivery vectors were constructed and injected YZ-1 Cas9 transgenic cotton plant leaves through Agrobacterium. In the above experiments, the plants transformed with the empty vector were used as controls. The genomic DNA of the transformed cotton leaves was subjected to PCR and enzyme digestion, and the PCR products which were not completely digested were cloned and sequenced. The results showed that no mutation in target gene was detected in the cotton plants transformed with the GhU6-5P::AE-sgRNA-1300, GhU6-5P::MAPKKK2-sgRNA-Cas9 and GhU6-5P::AE-sgRNA-Cas9, and the target genes mutation in the Cas9 transgenic plants transformed with GhU6-5P::MAPKKK2-sgRNA-1300, GhU6-5P-2::PDS-sgRNA-CLCrVA, GhU6-5P-2::CLA1-sgRNA-CLCrVA, GhU6-5P-2::MAPKKK2-sgRNA-CLCrVA and GhU6-5P-2::AE-sgRNA-CLCrVA vector was uncovered. The types of mutations included base substitution, base deletion and base insertion. The results indicated that the strategy of using Cas9 transgenic plants as transformation recipients can efficiently and truly verify the effectiveness of sgRNA, which eliminated false negative results due to low transformation efficiency, and the strategy of using virus as vectors to deliver sgRNA was more efficient and accurate. The establishment of this sgRNA high-efficiency verification system provides an important technical basis for cotton functional genomics research.

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    Anatomy and microscopic observation of Ricinus communis seed structure
    GUO Xue-Min,ZHAO Xiao-Man,XU Ke,WANG Xin-Rui,ZHANG Chen-Yu,DONG-FANG Yang
    Acta Agronomica Sinica    2020, 46 (6): 914-923.   DOI: 10.3724/SP.J.1006.2020.94141
    Abstract2772)   HTML44)    PDF(pc) (15210KB)(404)       Save

    We systematically observed the structure and distribution of vascular bundles of castor (Ricinus communis) testa, endosperm and embryo with germination, separation, paraffin sectioning technique, and microscopic observation techniques, stained with safranine and fast green, along with schiff’s reagent, respectively. (1) Micropyle at the dorsal base of the seed was not covered by the caruncle. (2) The testa consisted of three parts: episperm, endopleura and the caruncle, in which the episperm was composed of the long columnar epidermal layer, sponge parenchma and palisade parenchma from outside to inside, while the endopleura was composed of Malpighian layer, sponge parenchma and the inner integument layer, with an air chamber surrounded by the inner layer and outer layer of endopleura at the end of the caruncle, similar to that of eggs. (3) Both the episperm and endopleura were distributed with vascular bundles, and the large ones of the episperm only distributed in the spongy parenchma of the ventral raphe of the seed, which extended from the hilum to the opposite end of the caruncle; while those of endopleura were also distributed in the spongy parenchtma, and they branched step by step through the bundle band, ending at the edge of the air chamber at the end of the caruncle; those of both the episperm and endopleura were continuous through the junction point of the chalazal end to form the vascular system of the testa. (4) The caruncle was composed of epidermis and parenchyma, in which parenchyma consisted of small parenchyma cells on the outside and large parenchyma cells on the inside. In the middle and ventral part of the caruncle, there were only two vascular bundles, which constituted the vascular system of the caruncle independently. In the caruncle, caruncle channel was also found, with the inner end opening in the air chamber of the endopleura and the outer end being blind. (5) No vascular bundles were found in the endosperm, which consisted of parenchymal cells containing a large number of aleurone grains. In the embryo, the vascular bundles were collateral, which differentiated in the hypocotyle and entered the main vein of two cotyledons from both sides of the top of the hypocotyle respectively, gradually reduced from 4 to 1 in the main veins, and the branches became thinner in the cotyledon, forming the vascular system of embryo. The cotyledon epidermis and mesophyll cells contained aleurone grains, but no aleurone grains were found in the plumule, hypocotyle and radicle. Two cotyledons separated from each other on the adaxial surface, while their abaxial surfaces were connected with the endosperm through the mucilaginous layers. The hypocotyle and radicle were spatially separated from the endosperm. These results provide an anatomical basis for comprehensively understanding the structure of the seeds and studying the seed development and germination and their material transportation.

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    Grain filling characteristics of summer maize varieties under different sowing dates in the Huang-Huai-Hai region
    XU Tian-Jun, LYU Tian-Fang, ZHAO Jiu-Ran, WANG Rong-Huan, ZHANG Yong, CAI Wan-Tao, LIU Yue-E, LIU Xiu-Zhi, CHEN Chuan-Yong, XING Jin-Feng, WANG Yuan-Dong, LIU Chun-Ge
    Acta Agronomica Sinica    2021, 47 (3): 566-574.   DOI: 10.3724/SP.J.1006.2021.03023
    Abstract309)   HTML12)    PDF(pc) (1102KB)(401)       Save

    In order to provide helpful information for maize variety selection and realizing high yield, the grain filling characteristics of 18 summer maize varieties were investigated under 6/10 (S1), 6/20 (S2), and 6/30 (S3). The results showed that: (1) There were significant differences in the final 100-grain dry weight among varieties and sowing date treatments, characterized by S1 (35.20 g) > S2 (33.45 g) > S3 (31.38 g), and the range of variation was 28.50 g (HM 1) to 36.37 g (JNK 728). (2) The average filling rate (Gave) under different sowing date treatments was S1 (0.74 g 100-grain -1d-1) > S2 (0.65 g 100-grain -1d-1) > S3 (0.57 g 100-grain -1d-1). The average grain filling rate of S1 was 0.09 g 100-grain-1d-1and 0.17 g 100-grain-1d-1 higher than that of S2 and S3, increased by 13.85% and 29.82%, respectively. The Gave of JNK 728 (0.75 g 100-grain -1 d-1) was the highest among varieties, which significantly higher than ZD 958 and XY 335 (0.58 g 100-grain-1 d-1 and 0.67 g 100-grain-1 d-1), increased by 29.31% and 11.94%. The active grain filling period (P) showed that S1 (47.85 d) < S2 (51.39 d) < S3 (55.04 d). (3) The yield under different sowing date treatments was S1 (10,628.67 kg hm-2) > S2 (10,207.65 kg hm -2) > S3 (9144.59 kg hm -2), with S1 4.12% and 16.23% higher than S2 and S3, respectively. Among them, NK 815, MC 121, JNK 729, MC 812, JNK 728 and XY 335 had relatively high yields, with an average of 10,730.56 kg hm-2, significantly higher than ZD 958 (10,080.85 kg hm-2), increased by 6.44%. (4) Correlation analysis showed that yield level was significantly and positively correlated with Gave (0.70 **) and grain weight (0.68**), and was significantly and negatively correlated with P (-0.36 **); Grain weight was significantly correlated with Gave (0.58 **). In conclusion, maize yield, grain weight and grain filling rate reduced with the sowing date delay, but P increased accordingly, early sowing properly was beneficial to achieve higher yield in Huang-Huai-Hai summer maize region, by selecting varieties such as JNK 728, JNK 729, MC 812, MC 121, NK 815, and XY 335 which characterized by suitable growing period, higher grain filling rate, suitable active grain filling period and higher yield level. JNK 728, characterized by medium-early maturity, higher grain filling rate and yield, was suitable for the later sowing conditions or areas with insufficient accumulated temperature, and could reach physiological maturity in mid-October when sowing at the end of June.

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the Crop Science Society of China
the Institute of Crop Science, CAAS
China Science Publishing & Media Ltd.
Published: Science Press
Editor-in-chief: Wan Jian-min
Associate Editors-in-Chief:
Chen Xiao-ya Yang Jian-chang Zhang Xian-long Wang Jian-kang Xu Ming-liang Liu Chun-ming Wang Dao-wen Sun Chuan-qing Ding Yan-feng Jin Wei-wei Chu Cheng-cai Cheng Wei-hong
Director of the editorial department:
Cheng Wei-hong
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

  • Started in 2013
  • Covered by SCIE
  • Open access in ScienceDirect

Editor in chief: Wan Jian-min
CN 10-1112/S
ISSN 2095-5421, 2214-5141(online)
Online published:
Submission: https://www.editorialmanager.com/cj/
E-mail: cropjournal@caas.cn
Tel: 8610-82108548