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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
    Abstract422)   HTML25)    PDF(pc) (6984KB)(750)       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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    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
    Abstract475)   HTML52)    PDF(pc) (1292KB)(673)       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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    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
    Abstract803)   HTML115)    PDF(pc) (4569KB)(598)       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
    Abstract563)   HTML42)    PDF(pc) (4156KB)(576)       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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    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
    Abstract592)   HTML22)    PDF(pc) (854KB)(573)       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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    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
    Abstract647)   HTML106)    PDF(pc) (2376KB)(567)       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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    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
    Abstract237)   HTML6)    PDF(pc) (1106KB)(505)       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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    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
    Abstract592)   HTML33)    PDF(pc) (2839KB)(490)       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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    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
    Abstract523)   HTML7)    PDF(pc) (578KB)(477)       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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    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
    Abstract518)   HTML28)    PDF(pc) (25179KB)(469)       Save

    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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    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
    Abstract633)   HTML76)    PDF(pc) (2398KB)(450)       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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    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
    Abstract448)   HTML22)    PDF(pc) (622KB)(443)       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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    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
    Abstract516)   HTML64)    PDF(pc) (418KB)(441)       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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    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
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    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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    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
    Abstract430)   HTML7)    PDF(pc) (530KB)(432)       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 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
    Abstract347)   HTML72)    PDF(pc) (1301KB)(430)       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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    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
    Abstract321)   HTML17)    PDF(pc) (1959KB)(416)       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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    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
    Abstract272)   HTML41)    PDF(pc) (959KB)(399)       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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    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
    Abstract447)   HTML28)    PDF(pc) (545KB)(393)       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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    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
    Abstract709)   HTML56)    PDF(pc) (2510KB)(386)       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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    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
    Abstract510)   HTML11)    PDF(pc) (450KB)(375)       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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    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
    Abstract405)   HTML17)    PDF(pc) (636KB)(375)       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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    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
    Abstract387)   HTML26)    PDF(pc) (3110KB)(374)       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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    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
    Abstract820)   HTML25)    PDF(pc) (1659KB)(364)       Save

    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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    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
    Abstract308)   HTML24)    PDF(pc) (721KB)(363)       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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    Effect of OsPAL2;3 in regulation of rice allopathic inhibition on barnyardgrass ( Echinochloa crusgalli L.)
    LI Lan-Lan, MU Dan, YAN Xue, YANG Lu-Ke, LIN Wen-Xiong, FANG Chang-Xun
    Acta Agronomica Sinica    2021, 47 (2): 197-209.   DOI: 10.3724/SP.J.1006.2021.02034
    Abstract332)   HTML36)    PDF(pc) (13621KB)(362)    PDF(mobile) (13621KB)(37)    Save

    Phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) is the key enzyme in regulation of the synthesis of phenolic acid allelochemicals. PAL gene in rice belongs to a multigene family. In allelopathic accession rice PI312777 and non-allelopathic rice accession Lemont, the promoter sequences of the same PAL gene member were different, and there was the largest difference in OsPAL2;3 and OsPAL2;4 gene promoter sequence. Gene promoter of OsPAL2;3 from PI3127777 showed higher activity than the corresponding promoter from Lemont. Overexpression of OsPAL2;3 in PI312777 and Lemont resulted in increasing allelopathic inhibition on barnyardgrass (Echinochloa crusgalli L.), and the inhibitory ratios was increased by 11.11% in PI312777 and 5.56% in Lemont. Gene expression level of OsPAL2;3, OsC4H, OsCCA, OsCOL, and OsOMT was up-regulated in the OsPAL2;3-overexpressed transgenic rice compared with that of wild-type rice, and the contents of protocatechuic acid and vanillic acid were also increased. The results from Co-IP combined with mass spectrometry showed that transketolase, carbonic anhydrase, fructose-bisphospate aldolase isozyme, ATP synthase subunit alpha and ATP synthase subunit beta were interacted with OsPAL2;3 protein, resulting in regulating the phenylalanine pathway in rice. Our study indicated that the transcriptional activity of OsPAL2;3 contributed to the alleloapthic activity between PI312777 and Lemont, OsPAL2;3 was interacted with a couple of proteins to jointly regulate the synthesis of phenolic acids, and OsPAL2;3 could be considered as a candidate gene to improve the allelopathy of rice in breeding.

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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
    Abstract368)   HTML33)    PDF(pc) (11274KB)(357)       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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    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
    Abstract368)   HTML20)    PDF(pc) (1008KB)(351)       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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    A large-scale screening of maize germplasm for resistance to multiple diseases in multi-plot demonstration for several years under natural condition
    DUAN Can-Xing,DONG Huai-Yu,LI Xiao,LI Hong,LI Chun-Hui,SUN Su-Li,ZHU Zhen-Dong,WANG Xiao-Ming
    Acta Agronomica Sinica    2020, 46 (8): 1135-1145.   DOI: 10.3724/SP.J.1006.2020.03003
    Abstract515)   HTML49)    PDF(pc) (298KB)(343)       Save

    Disease is a major factor affecting maize production. The utilization of resistant cultivars is the most economical, safe, and effective method for controlling maize diseases. This research was finally conducted using 2000 maize germplasm accessions with extensive sources and rich genetic background to identify and evaluate the resistance to multiple diseases in multi-plot demonstration for several years under natural condition during 2016-2019. Nine diseases, including southern corn leaf blight, stalk rot, common smut, Curvularia leaf spot, southern rust, maize rough dwarf, northern corn leaf blight, gray leaf spot and head smut were investigated and evaluated in non-inoculated fields. The experimental data at 10 different sites from 2016 to 2019 showed that resistance identification under natural conditions was sensitive to environmental factors, with distinct differences among years and regions. The incidence of southern corn leaf blight was severe at multiple sites over these years and 11 maize accessions with stable resistance were screened out. Stalk rot, northern corn leaf blight, and gray leaf spot were relatively serious at several sites in four years, and 440, 356, and 423 resistant germplasm were screened out from 2000 accessions, respectively. These integrated data had considerable reference values. Curvularia leaf spot, common smut, and maize rough dwarf occurred heavily at only one plot while southern rust and head smut were not serious at all experimental sites, which should be studied further more. All in all, some maize germplasm resources with stable resistance to diverse diseases under different environments were screened out, such as JN15, 953, Shen 977, 68122, K21, SC24-1, 17MC7211, 17MC7223, Zheng 591, 161191, and so on. These results provide a significant reference for utilization and selection of germplasm for further precise inoculated identification.

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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
    Abstract248)   HTML9)    PDF(pc) (1102KB)(342)       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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    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
    Abstract289)   HTML23)    PDF(pc) (3196KB)(337)       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
    Abstract282)   HTML8)    PDF(pc) (4263KB)(333)       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
    Abstract2418)   HTML39)    PDF(pc) (15210KB)(332)       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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    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
    Abstract187)   HTML22)    PDF(pc) (10417KB)(332)       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.

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    Changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato
    JIANG Zhong-Yu, TANG Li-Xue, LIU Hong-Juan, SHI Chun-Yu
    Acta Agronomica Sinica    2020, 46 (11): 1750-1759.   DOI: 10.3724/SP.J.1006.2020.04097
    Abstract363)   HTML20)    PDF(pc) (549KB)(330)       Save

    In order to explore the changes of endogenous hormones on storage root formation and its relationship with storage root number under different potassium application rates of sweet potato root, sweet potato varieties ‘Yanshu 25’ and ‘Beijing 553’ with significant differences in storage root number were used as experimental materials, potassium oxide (K2O) was used as fertilizer, and four potassium fertilizer gradients of 0 (K0), 120 (K2), 240 (K3), and 360 kg hm-2 (K4) were set. The effects of different potassium application rates on the contents of endogenous hormones, the activity of related metabolic enzymes, the number of storage root and root evenness in swelling roots of sweet potato during root formation and harvest stage were studied. Compared with the treatment without potassium fertilizer (K0), the application of potassium fertilizer decreased the enzyme activities of indoleacetic acid oxidase (IAAO) and peroxidase (POD), increased the content of indole-3-acetic acid (IAA), increased the content of zeatin riboside (ZR) and decreased the content of gibberellins (GA3). Potassium application enhanced the activity of primary cambium and promoted the differentiation from adventitious root to storage root by regulating the content of endogenous hormones in swelling roots of sweet potato. Compared with the control, the application of potash fertilizer significantly increased the number and weight of storage roots per plant and root yield of ‘Yanshu 25’ and ‘Beijing 553’. The number of storage roots per plant of ‘Yanshu 25’ and ‘Beijing 553’ increased by 3.16%-25.40% and 3.85%-33.11%, respectively, and the yield increased by 4.22%-17.31% and 3.94%-18.45%, respectively. Compared with the potassium application treatments of the two varieties, the K2 treatment had the highest storage roots number per plant, the highest weight and yield of storage roots, with the best root evenness.

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    Cloning and expression analysis of lncRNA27195 and its target gene TaRTS in wheat ( Triticum aestivum L.)
    WANG Na, BAI Jian-Fang, MA You-Zhi, GUO Hao-Yu, WANG Yong-Bo, CHEN Zhao-Bo, ZHAO Chang-Ping, ZHANG Ling-Ping
    Acta Agronomica Sinica    2021, 47 (8): 1417-1426.   DOI: 10.3724/SP.J.1006.2021.01071
    Abstract349)   HTML31)    PDF(pc) (3770KB)(329)       Save

    Long non-coding RNA (lncRNA) is a non-coding RNA length over 200 bp, which is abundant in plants. It plays important roles in plant growth, development, and stress response by regulating gene expression or protein function. In the previous study, a fertility-related lncRNA named lncRNA27195 was screened and obtained by transcriptome sequencing from the anther of wheat Photoperiod-thermo Sensitive Genic Male Sterility (PTGMS) line BS366. To investigate the function of lncRNA27195 in wheat, the lncRNA27195 gene and its target gene TaRTS were cloned from BS366. Bioinformatics analysis were performed on TaRTS. The expressions of lncRNA27195 and TaRTS in different tissues and their expression correlation between them were analyzed by qRT-PCR. Meanwhile, the expression patterns of lncRNA27195 and TaRTS under different light and temperature treatments, and methyl jasmonate (MeJA) treatments were investigated. The results showed that the TaRTS gene with 315 bp length, encoded 104 amino acids. Additionally, RTS proteins were only found as anther-specific proteins in gramineae plants. Both lncRNA27195 and TaRTS with a significantly positive correlation were highly expressed in stamens, and revealed different expression patterns in different fertility environments. The results demonstrated that the expression of lncRNA27195 and TaRTS were also regulated by light and temperature. In addition, we found that the appropriate concentration of MeJA could promote the expression of lncRNA27195 and TaRTS while SA could inhibit the expression. The results indicated that under the induction of photoperiod, temperature, and plant hormones, IncRNA27195 positively regulated TaRTS gene expression, resulting in affecting pollen development and male fertility. This study contributed to the mechanism research and production application of PTGMS wheat.

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    Differences in photosynthetic performance of leaves at post-flowering stage in different cultivation modes of summer maize ( Zea mays L.)
    LI Jing, WANG Hong-Zhang, LIU Peng, ZHANG Ji-Wang, ZHAO Bin, REN Bai-Zhao
    Acta Agronomica Sinica    2021, 47 (7): 1351-1359.   DOI: 10.3724/SP.J.1006.2021.03051
    Abstract320)   HTML34)    PDF(pc) (710KB)(325)       Save

    Photosynthesis plays an important role in crop growth and yield formation. Different cultivation patterns can significantly affect the photosynthetic performance of leaves at post-flowering stage in summer maize. In order to explore the effects of different cultivation modes on the photosynthetic performance of summer maize leaves at post-flowering stage, field experiments were carried out with Denghai 605 maize hybrid variety as experimental material from 2018 to 2019 in Tai’an, Shandong, China. With the local farmer management mode (FP) as the control, the super-high-yield cultivation mode (SH) and high-yield and high-efficiency cultivation mode (HH) by comprehensively optimizing the planting density, fertilizer planting and management mode were set in this study. Leaf area index, chlorophyll content, gas exchange parameters, rapid chlorophyll fluorescence induction kinetic curve (OJIP) were evaluated, which indicated significant differences in biomass of different cultivation modes at maturity stage. Compared with FP, the biomass of SH and HH increased by 27.77% and 7.43%, respectively, and the population biomass at post-flowering stage of HH increased significantly as well. Besides, the photosynthetic rate all declined in different cultivation modes, reaching the highest degree of decline on the 30th day at post-flowering stage (R1+30 d). In contrast with FP, the net photosynthetic rate (Pn) of SH and HH increased at post-flowering stage stage (R1) by 21.63% and 12.96%, respectively, and on the 30th day (R1+30 d) at post-flowering stage by 35.37% and 12.37%, respectively, which could maintain a higher level of photosynthetic capacity. In addition, these results revealed that the differences of net photosynthetic rate among the different cultivation modes were caused by non-stomatal factors. The stomatal conductance (Gs) of SH and HH was increased at the silking stage by 18.36%, 16.66%, 26.16%, and 10.74%, respectively, and while on the 30th day at post-flowering stage intercellular carbon dioxide (Ci) declined by 12.85%, 7.34%, 14.08%, and 9.75%, respectively. Compared with FP, Wk and Vj of SH and HH significantly decreased, indicating that SH and HH apparently improved the performances of both electron donor and acceptor sides of electron transport chain in PSII reaction center, the quantum yield of electron transfer (φE0), the electron transfer ability as well as the reaction center activities of PSII and the coordination between PSI and PSII. In conclusion, SH and HH effectively improved the photosystems performance, increased the net photosynthetic rate, and prolonged duration of high photosynthesis rate, resulting in the increase of the population biomass and high yield.

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    Phenotype analysis and gene mapping of small kernel 7 ( smk7) mutant in maize
    JIANG Cheng-Gong, SHI Hui-Min, WANG Hong-Wu, LI Kun, HUANG Chang-Ling, LIU Zhi-Fang, WU Yu-Jin, LI Shu-Qiang, HU Xiao-Jiao, MA Qing
    Acta Agronomica Sinica    2021, 47 (2): 285-293.   DOI: 10.3724/SP.J.1006.2021.03015
    Abstract540)   HTML20)    PDF(pc) (4699KB)(321)       Save

    In this study, a stable small kernel mutant, named small kernel 7 (smk7), was isolated from ethylmethane sulfonate (EMS) mutagenesis of maize inbred line B73. Compared with wild type, the smk7 mutants showed smaller kernel size, defective embryo and endosperm development and a significant decrease in 100-kernel weight. The smk7 kernels showed a low level of germination rate at 10% and cannot grow into normal plants. No significant changes were detected in protein, starch and oil content between mature wild type and smk7 kernels, but the starch grains became significantly smaller and irregular in smk7 kernels compared with wild type. The smk7 kernels could be clearly distinguished from the wild type as early as 12 days after pollination (DAP), on the basis of their smaller and emptier phenotype. Microscopic inspection of the paraffin sections revealed that the development of embryo and endosperm were delayed, and the cell wall in growth in basal endosperm transfer layers (BETL) were arrested in smk7 compared with wild type. The F2 populations with multiple backgrounds were constructed by crossing heterozygous plants (+/smk7) with several other inbred lines. Genetic analysis showed that the mutant phenotype was controlled by a single recessive gene. Based on genotyping by target sequencing (GBTS) strategy, the SMK7 was initially mapped on the short arm of chromosome 2. The fine mapping results suggested that SMK7 was located between markers RM1433917 and RM1535316, with a physical distance of 120 kb. There were eight protein-coding genes in this region. This study laid a foundation for further genes cloning and research of the SMK7 function in regulating maize kernel development.

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    Cloning and functional analysis of ZmbHLH161 gene in maize
    Meng-Ting YANG, Chun ZHANG, Zuo-Ping WANG, Hua-Wen ZOU, Zhong-Yi WU
    Acta Agronomica Sinica    2020, 46 (12): 2008-2016.   DOI: 10.3724/SP.J.1006.2020.03022
    Abstract333)   HTML14)    PDF(pc) (4689KB)(316)       Save

    bHLH transcription factors are the second largest family of transcription factors in plants and play an important role in regulating plant growth and development, signal transduction, and stress response. In order to study the function of maize bHLH family genes in response to stress, ZmbHLH161 (AC: NC_AQK75074) gene from maize root tissue was cloned in this study. Bioinformatic analysis showed that this gene contains 3 exons, the full-length of its cDNA is 1460 bp, coding sequence is 1059 bp in length, encoding 352 amino acids. It exists as a single copy in the maize genome and its function is unknown. The molecular weight of ZmbHLH161 protein is 37.1 kD, and its theoretical isoelectric point is 6.10, with a conserved domain unique to the bHLH transcription factor family, but does not have a transmembrane structure or signal peptide. It is a hydrophilic protein, and the secondary structure of the protein has a maximum proportion of 42.05%. Transient expression experiments in maize protoplasts showed that ZmbHLH161 was localized in the nucleus. Real-time quantitative PCR (qPCR) analysis showed that under normal growth conditions, ZmbHLH161 was mainly expressed in roots and immature embryos, while under dehydration and drought treatment, ZmbHLH161 was up-regulated in maize seedling leaves. After treated with different concentrations of NaCl, the root length of ZmbHLH161 transgenic heterologous Arabidopsis strains was not significantly different from that of wild type, and their root was longer than that of wild type after being treated with different concentrations of mannitol. It is speculated that ZmbHLH161 gene may be involved in the response of maize to osmotic stress.

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Co-sponsored:
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

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  • 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:
https://www.sciencedirect.com/journal/the-crop-journal
Submission: https://www.editorialmanager.com/cj/
E-mail: cropjournal@caas.cn
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