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Table of Content

    12 February 2012, Volume 38 Issue 02
    • REVIEW
      Identification, Cloning, and Potential Application of Genes Related to Somatic Embryogenesis in Plant Tissue Culture
      YE Xing-Guo, SHE Mao-Yun, WANG Ke, DU Li-Pu, XU Hui-Jun
      Acta Agron Sin. 2012, 38(02):  191-201.  doi:10.3724/SP.J.1006.2012.00191
      Abstract ( 3270 )   PDF (2584KB) ( 4222 )   Save
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      Plant embryogenesis or organogenesis in vitro is a complicated asexual reproductive process consisting of many aspects such as phytohormone perception, dedifferentiation of differentiated cells to acquire organogenic competence, re-entry of quiescent cells into cell cycle, and organization of cell division to form specific organ primordia and meristems. In fact, plant regeneration is the result of multigenic interactions and regulatory controls, which are not only affected by plant hormones and other nutrients in the medium, but also showed a close relationship with the physiological state of explants. The effects of exogenous and endogenous hormones on plant regeneration and the regulation of exogenous hormones on endogenous hormones were reviewed in this paper. Research progresses on five classes of genes related to somatic embryogenesis were collectively described. They are somatic embryogenesis receptor-like kinase, arabinogalactan-proteins, nitrite reductase, auxin binding protein, and antioxidant enzyme. Regeneration associated genes are prospected to be potentially used in plant genetic breeding, whose applications will be involved in the improvement of plant regeneration efficiency and transformation efficiency, also in obtaining transgenic plants with bio-safety. However, main candidate genes related to regeneration might vary in different plants or tissues, or function through different pathways. Therefore, cloning and characterization of some important genes related to somatic embryogenesis or organogenesis should be strengthened in future.
      Inheritance of Resistances to Soybean Mosaic Virus Strains SC4 and SC8 in Soybean
      WANG Da-Gang, MA Ying, LIU Ning, ZHENG Gui-Jie, YANG Zhong-Lu, YANG Yong-Qiang, ZHI Hai-Jian
      Acta Agron Sin. 2012, 38(02):  202-209.  doi:10.3724/SP.J.1006.2012.00202
      Abstract ( 1829 )   PDF (154KB) ( 648 )   Save
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      Soybean mosaic virus (SMV) disease is one of the most destructive viral diseases worldwide, resulting in significant yield losses and seed-quality deterioration in soybean [Glycine max (L.) Merr.]. Utilization of resistant varieties is the most economical and environmentally safe approach to controlling this disease. The SMV strains SC4 and SC8 were predominant and widespreading in Huang-Huai-Hai and Yangtze valley in China. Twelve soybean resistant (R) cultivars were crossed respectively with susceptible (S) cultivars (Nannong1138-2, NY30, NY185, 86-4 or 8101) to determine resistance to SC4 or SC8. Resistant parent was also crossed with each other to identify whether resistant genes from different cultivars are at the same or at different loci by the test of allelic relationships of the resistance genes. The experiments were performed under greenhouse/net-house conditions. The F2 populations and F2:3 lines derived from all the possible crosses (R×S) exhibited a segregation pattern of 3R:1S and 1R:2segregating:1S ratio respectively when inoculated with the SMV strains SC4 and (or) SC8. The results indicated that Ji LD42, Xudou 1, Yuejin 4 and Qihuang 1, Zhongzuo 229, NY 58 carried a dominant resistant gene for SMV strains SC4 and SC8 respectively; Kefeng 1, PI96983, Jinda74, Fendou 56, Dabaima, and Qihuang 22 carried single dominant resistant gene for both SC4 and SC8. The test of the allelism of the resistance genes to SC4 showed that the F2 populations from R×R crosses exhibited a segregation pattern of 15R:1S. The results suggested that the resistance genes between Dabaima and Fendou56, Kefeng 1, Qihuang 1; between Ji LD42 and Fendou56; and between Jinda74 and Zhongzuo229 were not at the same locus. Resistance reactions of F2 and F2:3 families to SC8 indicated that single dominant resistant gene in Jinda74 and Fendou56 was at a same locus or closely linked two loci. The resistance genes between Qihuang 1 and Kefeng 1 and between Dabaima and Fendou56 were not at same locus for SC8. These results are useful to understand the genetic and allelomorphic relationship among various sources of resistance and make the better use of available germplasm in soybean resistance breeding programs.
      CROP GENETICS & BREEDING·GERMPLASM RESOURCES·MOLECULAR GENETICS
      Analysis of Quantitative Trait Loci for Resistance to Brown Planthopper in Dongxiang Wild Rice (Oryza rufipogon Griff.)
      HUANG De-Run, CHEN Ji, LAI Feng-Xiang, LIU Guang-Jie, ZHUANG Jie-Yun
      Acta Agron Sin. 2012, 38(02):  210-214.  doi:10.3724/SP.J.1006.2012.00210
      Abstract ( 1757 )   PDF (110KB) ( 1117 )   Save
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      Wild species of Oryza is an important resource of the genes for resistance to brown planthopper (BPH). In this study, two populations were developed from an interspecific cross between Dongxiang wild rice (Oryza rufipogon Griff.) and cultivated rice Xieqingzao B (Oryza sativa L.) and used to determine quantitative trait loci (QTLs) for BPH resistance. A BC1F5 population derived from Xieqingzao B//Xieqingzao B/Dongxiang wild rice was infested with BPH collected from the paddy field. Two QTLs were detected, of which qBph2 was located in the interval RM29–RG157 on chromosome 2 and qBph7 in the interval RM11–RM234 on chromosome 7, and the Dongxiang wild rice allele decreased seedling mortality by 22.2% and 43.7%, respectively. Validation of the two QTLs was followed by testing a BC3F3 population with BPH biotypes I, II, and III, respectively. QTL analysis showed that qBph2 confers resistance to biotypes I and II, while qBph7 to biotypes I and III. The two QTLs have a great potential in the improvement of BPH resistance of rice varieties.
      Improvement Efficiency of Recurrent Selection for the Combining Ability of Yield Trait in Maize Population Yuzong 5
      KU Li-Xia, MENG Qiang-Lei, HOU Ben-Jun, LI Jia-Fu, LIU Hai-Jing, CHEN Pan-Hui
      Acta Agron Sin. 2012, 38(02):  215-222.  doi:10.3724/SP.J.1006.2012.00215
      Abstract ( 1770 )   PDF (200KB) ( 1100 )   Save
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      Maize population has the extensive hereditary basis and rich hereditary variation, and therefore is the source of good inbred lines cultivated. Improvement of maize population is important to create new germplasm and breed excellent inbred lines. In this study, 30 testcrossing combinations that Huangzaosi, Dan 340, Zhong Syn 5, Qi 319, Ye 478, and Mo17 crossed with five cycle improved populations according to NC II design were evaluated in two environments. The results showed that the recurrent selection method gained a good result for yield per plant of the population and the gain of hybrid grain yields of testcross combinations between improved populations per cycle and testing cultivars increased by 10%. Both half-sib recurrent selection (HS-RS) and half-sib reciprocal recurrent selection (HS-RRS) were good methods for improving the general combining ability (GCA) of grain yield in the populations and the GCA was improved in very cycle for the populations. After improvement of three cycles for Yuzong 5 by HS-RS, the GCA increased from -11.63 to 5.57 with highly significant probability difference at the level by C3 comparing with C0. After improvement of one cycle for Yuzong 5 by HS-RRS, the GCA increased from 5.57 to 9.75 by C4 comparing with C3. The analysis of special combining ability (SCA) showed that the SCA of improved Yuzong 5 × Huangzaosi had certain enhancement, indicating that improvement of Yuzong 5 developed steadily toward the heterotic pattern of Reid×SiPT.
      Transferability of Mungbean Genomic-SSR Markers in Other Vigna Species
      ZHONG Min, CHENG Xu-Zhen, WANG Li-Xia, WANG Su-Hua, WANG Xiao-Bao
      Acta Agron Sin. 2012, 38(02):  223-230.  doi:10.3724/SP.J.1006.2012.00223
      Abstract ( 2012 )   PDF (454KB) ( 966 )   Save
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      Cowpea (Vigna unguiculata L. Walp.), mungbean (V. radiata L. Wilczek), rice bean [V. umbellate (Thunb.) Ohwi & Ohashi] and adzuki bean (V. angularis Willd. Ohwi and Ohashi) are major food legumes in China. At present, SSR markers for genetic analysis of these legumes are much limited. Transferability analysis of primers has the vital significance to reduce their development cost and improve their development efficiency. In this study, 1 205 SSRs primers were tested for their transferability and polymorphism by PCR amplification with the genomic DNA of four Vigna species, cowpea, adzuki bean, mungbean and rice bean. The results indicated that the transferability rate of mungbean genomic-SSR in cowpea, adzuki bean and rice bean was 50.0%, 73.3%, and 81.6%, and the ratio of polymorphism SSR primers in these crops was 4.1%, 1.7%, and 1.5%, whereas 32.0% in mungbean. A total of 469 mungbean genomic-SSR primers were detected to be highly transferable among different species of Vigna. The transferability of mungbean genomic-SSR was higher in adzuki bean and rice bean than in cowpea. These transferable markers are useful for further genetic and breeding studies in these species.
      Gene Expression Profiling and Silencing Reveal the Relationship between TaTST, a Wheat Thiosulfate Sulfurtransferase Gene, and the Resistance Response of Wheat to Powdery Mildew
      HE Yang, YUE Jie-Yu, WANG Hua-Zhong
      Acta Agron Sin. 2012, 38(02):  231-239.  doi:10.3724/SP.J.1006.2012.00231
      Abstract ( 1876 )   PDF (401KB) ( 958 )   Save
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      Plant thiosulfate sulfurtransferase (TST), which participates in sulfur metabolism, removal of cyanide, generation and removal of reactive oxygen species (ROS), is closely related to plant disease resistance. The wheat TST-encoding gene TaTST was induced by the powdery mildew pathogen fungus Blumeria graminis f.sp. tritici (Bgt) in both theresistant and the susceptible wheat near-isogenic lines. Two expression peaks of TaTST were found from 0 to 48 h after inoculation of Bgt, corresponding to the initial contact and recognition between the host cell and Bgt and the invasion attempt of appressoria and haustoria formation. The two expression peaks were also in agreement with the two oxygen burst reactions. The induced expression level of TaTST was significantly higher in the susceptible line than in the resistant line, which may result in excessive removal of ROS as a response to Bgt infection and so contribute to the process of diseasesusceptibility. TaTST also involved in the process of disease resistance. The method of virus-induced gene silencing (VIGS) was used to silence the TaTST gene of the resistant line. Although TaTST-silencing plants did not produce visible mildew spots or lesions, they showed reduction of resistance to powdery mildew with the increased successful penetration rate and limited elongation of secondary hypha. Decreased density of papilla and delayed H2O2 spreading in the Bgt-challenged host cells of the VIGS plants suggest that TaTST possibly affects the Bgt penetration process in resistance response through participating in the ROS accumulation and spread and the papilla formation at early stage of wheat-Bgt interaction.
      Genetic Analysis and Gene Mapping of a Novel Short Root Hair Mutant in Rice
      DING Wo-Na, HUANG Wei, NING Yong-Qiang, ZHU Shi-Hua
      Acta Agron Sin. 2012, 38(02):  240-244.  doi:10.3724/SP.J.1006.2012.00240
      Abstract ( 2097 )   PDF (273KB) ( 1197 )   Save
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      In plants, root hairs are important organs for the uptake of nutrients and water.A rice (Oryza sativa L.) mutant with short root hairs (ossrh3) was isolated from a T-DNA insertion mutant library of rice with Zhonghua 11 background. The elongation of root hairs in the mutant was severely impaired, and other traits were also affected including the plant height, primary root length, lateral root length and number of lateral roots. Genetic analysis indicated that the mutant phenotype was controlled by a single recessive nuclear gene. For mapping the OsSRH3 gene, an F2 population was generated by crossing the mutant ossrh3 with Kasalath wild type. Ultimately by using the published SSR (simple sequence repeat) markers and some newly designed STS (sequence-tagged site) markers, the OsSRH3 was mapped to a 37.7 kb region between the markers S38978 and S39016 on chromosome 1. Within this region, there were eight predicted genes. The study will be helpful for the cloning of OsSRH3 and characterization of the molecular genetic mechanisms of the root hair development in gramineous plants.
      Cloning and Expression Analysis of Lysophosphatidic Acid Acyltransferase (LPAT) Encoding Gene in Peanut
      CHEN Si-Long, HUANG Jia-Quan, LEI Yong, REN Xiao-Ping, WEN Qi-Gen, CHEN Yu-Ning, JIANG Hui-Fang, YAN Li-Yang, LIAO Bo-Shou
      Acta Agron Sin. 2012, 38(02):  245-255.  doi:10.3724/SP.J.1006.2012.00245
      Abstract ( 2302 )   PDF (607KB) ( 1820 )   Save
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       Lysophosphatidic acid acyltransferase (LPAT) is a key enzyme in biosynthesis pathway of vegetable oil in plant. It is important for oil crops to improve oil quality and increase seed oil content through genetic engineering. We constructed a full-length cDNA library of peanut (Arachis hypogaea) seed via a large number of sequences of expressed sequence tag (EST) and gene functional annotation, a lysophosphatidic acid acyltransferase gene, designated AhLPAT, and its genomic DNA sequence were isolated from peanut. The sequence of AhLPAT cDNA was 1 629 bp, and its genomic sequence was 5 331 bp. Bioinformatic analysis showed that AhLPAT was composed of eleven exons and ten introns with typical GT-AG characteristic in comparison of its sequences of genomic DNA and cDNA by Splign in NCBI. A peptide of 387 amino acid residues with protein molecular weight of 43.2 kD and isoelectric point (pI) of 9.42 were deduced from AhLPAT. Conserved domains prediction indicated that AhLPAT comprised a typical conserved acyltransferase domain and a conserved lysophospholipid acyltransferases domain. The deduced amino acid had a high identity with the LPAT proteins reported from other species. Amino acid similarities of LPAT protein between peanut and Tropaeolum majus, Brassica napus, Crambe hispanica subsp. Abyssinica, Ricinus communis, and Arabidopsis thaliana were 90%, 89%, 89%, 88%, and 87%, respectively. A phylogenetic tree was constructed by the Neighbour-Joining method using MEGA5.0. The phylogenetic tree suggested that AhLPAT and AtLPAT2 derived from Arabidopsis thaliana were grouped into the same class and both AhLPAT and AtLPAT2 were endoplasmic reticulum type LPATs. The tissue specific expression analysis by using quantitative RT-PCR assays indicated that AhLPAT was ubiquitously expressed in root, stem, leaf, flower, gynophore and seed of peanut with the highest level in gynephore and seed. The expression level reached a peak in the stage from 50 to 60 days after flowering. The expression level of AhLPAT kept consistent with the rate of oil accumulation, indicating a significant correlation between AhLPAT expression level and oil content (r=0.63, P<0.05). These results suggested that AhLPAT plays an important role in peanut triacylglycerol synthesis.
      Mapping and Meta-Analysis of QTLs for Leaf Traits in Soybean
      SHI Xiang-Lin, SUN Ya-Nan, WANG Jia-Lin, LIU Chun-Yan, CHEN Qing-Shan, HU Guo-Hua
      Acta Agron Sin. 2012, 38(02):  256-263.  doi:10.3724/SP.J.1006.2012.00256
      Abstract ( 2140 )   PDF (274KB) ( 1379 )   Save
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      Leaf length, width and leafstalk length affect the photosynthetic capability of plant and so increasing photosynthetic rate per unit leaf area may improve seed yield in soybean. In this study, we analyzed QTLs data of soybean leaf length, width and leafstalk length from 2006 to 2010with a F2:14–F2:18 of recombination inbred lines (RIL) population derived from a cross between Charleston and Dongnong 594 by mixed linear model approach. Eight QTLs for leaf length(LL) were mapped on the chromosomes Gm01, Gm02, Gm05, Gm11, Gm18 by software WinQTLCartographer Ver. 2.5, nine QTLs were identi?ed for leaf width (LW) on the chromosomes Gm01, Gm03, Gm05, Gm06, Gm11, Gm12, Gm16; eight QTLs were identi?ed for leafstalk length (LSL) on Gm01, Gm03, Gm05, Gm06, Gm11, Gm17, Gm18. qLL5a, qLL5b, qLL1a, and qLL18 for LL, qLW5a, qLW11a, qLW11b, and qLW12 for LW, and qLSL11b for LSL were identi?ed in more than two years. Furthermore, not only 72 QTLs of leaf traits that have been mapped in many different populations and environments were collected but also QTL mapped by WinQTLCartographer Ver. 2.5 were projected and integrated in the reference map with the software BioMercator2.1. In total, the consensus QTLs of five for leaf length and four for leaf width were obtained in soybean, respectively. The minimum confidence interval of leaf length was shrunk to 5.66 cM. These results would provide a basis for fine mapping QTL and cloning genes in soybean.
      Identification of QTL for Rice Starch RVA Profile Properties under Different Ecological Sites
      YANG Ya-Chun, NI Da-Hu, SONG Feng-Shun, LI Li, LU Xu-Zhong, LI Ze-Fu, YANG Jian-Bo
      Acta Agron Sin. 2012, 38(02):  264-274.  doi:10.3724/SP.J.1006.2012.00264
      Abstract ( 2263 )   PDF (695KB) ( 1115 )   Save
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      Two rice varieties with similar apparent amylose content, Nipponbare (japonica) and 93-11 (indica), were used as parents to establish a recombinant inbred lines population consisting of 190 lines by single seed descent method. The genetic linkage map was constructed with 202 SSR, CAPs and STS markers. Quantitative trait loci (QTLs) were identified for eight rice starch RVA profile properties including peak paste viscosity(PKV), hot paste viscosity(HPV), cool paste viscosity(CPV), breakdown viscosity(BDV), setback viscosity(SBV), consistence viscosity(CSV), peaktime (PeT), pasting temperature (PaT) by composite interval mapping method in three different ecological sites (Lingshui, Hefei, and Huaiyuan). A total of 57 QTLs were identified, with 1 to 14 for each trait, indicating that rice starch RVA profile properties were controlled by multiple genes. Thirteen stable QTLs were detected at two or three sites, among which qCPV-3, qCPV-10b, qSBV-10b, qCSV-3b,and qCSV-10b (explaining, 26.9%, 29.5%, 29.7%, 25.2%, and 28.3% of variance) were detected in all the three sites. Sixteen QTLs were found to have pleiotropy with a single QTL controlling two to six traits (RVA profile properties), the interval RM25032–RM1375 on chromosome 10 controlling six traits (PKV, HPV, CPV, SBV, PaT and CSV).
      QTL Mapping for Anthocyanin and Melanin Contents in Maize Kernel
      QIN Hong-Ni, YAN Meng, WANG Zhao-Hui, GUO Ying, WANG Hui, SUN Hai-Yan, LIU Zhi-Zhai, CAI Yi-Lin
      Acta Agron Sin. 2012, 38(02):  275-284.  doi:10.3724/SP.J.1006.2012.00275
      Abstract ( 2205 )   PDF (459KB) ( 1289 )   Save
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      Anthocyanin and melanin are important and beneficial chemical components in black maize kernel. It is important to comprehensively study the QTL mapping for anthocyanin and melanin, cloning and transfer of pigmentation-related genes and marker assistant breeding. In this paper, two related F2:3 populations derived from crosses of Mu6×SDM (WD) and Mo17×SDM (YD) were used to identify QTLs for anthocyanin and melanin contents in maize kernels. The results showed that the phenotype and QTL identification of two populations were highly consistent. The anthocynian and melanin contents of SDM were significantly higher than those of Mu6 and Mo17. The positive correlation between the two pigment contents in kernel was highly significant. A total of seventeen QTLs were identified, including eight QTLs for ACK and nine QTLs for MCK. For ACK, four QTLs were both detected in two populations, which were distributed on chromosomes 4, 6, 7, and 10. For MCK, four and five QTLs were identified in WD and YD, respectively, which were distributed on chromosomes 1, 2, 6, 7, and 10. The number, distribution and effects of QTLs in two populations were highly consistent, and the major QTLs of ACK and MCK in two populations were both clustered, which were detected in the interval umc1796–mmc2006 (bin 6.04) andumc2043–bnlg1028(bins 10.04) and explained 12.7%–21.3% and 8.6%–21.3% of phenotype variation, respectively. These QTLs which were stable in different genetic backgrounds might be closely linked to each other, or a same pleiotropic QTL which could be used in fine mapping and cloning of pigmentation-related genes in maize. The result of epistasic analysis indicated that the number, position and effects of epistatic QTLs between two populations were much different, and epistasic effects were more obvious for WD than for YD. Some epistatic QTL pairs explaining more than 10% variation of phenotype play an important role in pigment production and should be further studied.
      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      High Light Tolerance is Enhanced by Overexpressed PEPC in Rice under Drought Stress
      DING Zai-Song, ZHOU Bao-Yuan, SUN Xue-Fang, ZHAO Ming
      Acta Agron Sin. 2012, 38(02):  285-292.  doi:10.3724/SP.J.1006.2012.00285
      Abstract ( 2215 )   PDF (402KB) ( 1198 )   Save
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      Overexpression of phosphoenolpyruvate carboxylase (PEPC) gene in transgenic rice to improve photosynthesis and stress resistance have brought extensive interest in the world. Our previous report proved that the overexpressed PEPC alleviate drought stress inhibition on photosynthesis. In the present research, photosynthetic light curve, chlorophyll a fluorescence parameters, pigment content and reactive oxygen metabolism were studied under drought stress at flowering stage in 2 lines of PEPC transgenic rice plants. The results showed that under drought especially severe drought stress, net photosynthetic rate decreased dramatically under high photosynthetic active radiation (PAR) in wild type untransformed rice, while maintained unchanged in PEPC transgenic lines under high PAR even more than 1 200 μmol m-2 s-1. And the photochemistry activities (Fv/Fm, ΦPSⅡ, qP) decreased less under drought stress in both the PEPC transgenic lines. These indicated PEPC enhanced the photoinhibition tolerance of rice under drought stress. The higher zeaxanthin content under drought stress made the PEPC transgenic rice leaves disperse more light energy as heat, thus decreased the O2? producing rate in PSII. At the same time, the SOD, POD and CAT activities were higher in PEPC transgenic rice plants under drought stress, they could effectively diminished the reactive oxygen species and reduced the membrane lipid peroxidation.
      Effects of Growth-Period Type and Nitrogen Application Level on the RVA Profile Characteristics for Japonica Rice Genotypes
      LI Min, ZHANG Hong-Cheng, LI Guo-Ye, MA Qun, YANG Xiong, WEI Hai-Yan
      Acta Agron Sin. 2012, 38(02):  293-300.  doi:10.3724/SP.J.1006.2012.00293
      Abstract ( 1647 )   PDF (316KB) ( 900 )   Save
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      A field experiment was conducted using 46 japonica rice varieties belonging to three growth-period types in the middle and lower reaches of the Yangtze River. The results were as follows: (1) Generally, with increasing nitrogen application rate, the peak viscosity and the breakdown value decreased, the setback value and the pasting temperature increased accordingly, while the hot viscosity, the final viscosity and the consistency value showed no apparent changes. (2) The peak viscosity and the breakdown value decreased sharply with delaying growth duration among different growth-types of rice cultivars, the setback value, the consistency value and the pasting temperature increased, while the hot viscosity and the final viscosity increased at first and then decreased. (3) As the growth-period prolonged, the influence of nitrogen application rate on the RVA profile changed from the positive to the insensitive and at last to the entirely invalid. (4) Correlation analysis proved that, final viscosity, breakdown, consistency, setback value and pasting temperature were significantly or very significantly correlated with gel viscosity and taste value. Using the regression equation containing breakdown, final viscosity, pasting temperature and taste value, the taste quality could be predicted quantitatively from RVA values.
      Effects of Different Nitrogen Regimes on Canopy Structure and Partial Phsiological and Agronomic Characters
      XU Li-Na, HUANG Shou-Bing, TAO Hong-Bin, WANG Yun-Qi, QI Li-Pan, WANG Pu
      Acta Agron Sin. 2012, 38(02):  301-306.  doi:10.3724/SP.J.1006.2012.00301
      Abstract ( 1779 )   PDF (349KB) ( 1177 )   Save
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      Over-fertilized nitrogen leds to irrational crop canopy in summer maize, and thus negatively affected yield production. Therefore, it is important to study the nitrogen application time and level for the construction of efficient crop canopy. A field experiment was conducted using summer maize Zhengdan 958 with four nitrogen application regimes including low basal nitrogen fertilizer (30 kg ha-1), high basal nitrogen fertilizer (120 kg ha-1), first nitrogen dressing at jointing stage (30 kg ha-1), and zero-nitrogen. The results showed that canopy structure and other indexes were improved by nitrogen input. Slightly reducing of basal nitrogen provided the following advantages: (1) the amount of nitrogen fertilizer was significantly reduced without negative effect to maize seedlings, i.e. 90 kg ha-1 nitrogen saved; (2) the canopy structure was improved with high light transmission rate at the bottom of canopy and more compact leaf structure. Compared with the treatment of high basal nitrogen fertilizer, the leaf angel above ear of canopy and mean leaf angel decreased 4.33° and 4.67° respectively in the treatment oflow basal nitrogen fertilizer. Simultaneously, plant height and ear height were both reduced and the length of the basal stem internodes shortened, which effectively prevented stem from lodging;(3) underlow basal nitrogen fertilizer, canopy SPAD value and nitrogen concentration of the leaf were equivalent with high basal nitrogen treatment; (4) the grain yield was higher under low basal nitrogen fertilizer than under other nitrogen regimes due to the increase of ear number, thousand grain weight, grain number per ear and the decrease of bald tip length of the ear. First nitrogen dressing at jointing stage led to worse nitrogen condition before jointing stage, and thus limited yield formation and crop growth due to runtish seedlings and imbalanced nutrition.
      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Effect of Seeding and Transplanting Methods on Yield and Uniformity of Population Indices of Super Japonica Rice Ningjing 3
      WANG Duan-Fei, LI Gang-Hua, GENG Chun-Miao, DU Yong-Lin, LI Quan, DING Yan-Feng
      Acta Agron Sin. 2012, 38(02):  307-314.  doi:10.3724/SP.J.1006.2012.00307
      Abstract ( 1803 )   PDF (504KB) ( 970 )   Save
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      To study the influence of different cultivation methods on rice yield and uniformity of populationindices, We conducted a field experiment with seven treatments including machine transplanting (MT), broadcast seeding (BS), drill seeding (DS) and hole seeding (HS), precision hand transplanting (PT), cycle hand transplanting (CT), and equidistance hand transplanting (ET) in 2009 and 2010, using super-rice Ningjing 3 as material. The results showed that the grain yield of PT was the highest, followed by MT, ET, BS, CT, HS, and DS. Uniformity of population indices was the main influence factor of yield, the coefficient of variation (CV) of spikelets per panicle, primary and secondary branch number and panicle position distribution of Ningjing 3 were significantly positively correlated with grain yield. The difference of population uniformity of Ningjing 3 between machine transplanting, hand transplanting and direct-seeding was mainly due to the different durations of vegetative growth period. PT treatment had longer vegetative growth duration of tillers in all leaf ages, bigger panicle and more uniformity. In DS treatment, uniformity of population indices of Ningjing 3 was poor with the less tiller number, short vegetative growth period and small panicle, thus the yield was the lowest.
      Comparative Analysis of Seedling Drought Tolerance of Different Era Maize Varieties
      SUN Qi, ZHANG Shi-Huang, HAO Zhuai-Fang, ZHANG De-Gui, CI Xiao-Ke, CHEN Chao-Hui, LI Xin-Hai, XIE Chuan-Xiao, WENG Jian-Feng, BAI Li, LI Ming-Shun
      Acta Agron Sin. 2012, 38(02):  315-321.  doi:10.3724/SP.J.1006.2012.00315
      Abstract ( 1918 )   PDF (406KB) ( 1478 )   Save
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      Spring drought often occurs in Northern region, which affects the production of Maize. So seedling drought tolerance is an important factor to account for in Maize breeding. Thirty-five varieties included four OPVs (1950s), four double hybrids (1960s) and twenty-seven single hybrids (1970s–2000s). Seedling drought tolerance was evaluated in drought house. Biomass of seedling was investigated, including fresh weight and dry weight. Coefficient of seedling drought tolerance was calculated. The trend and response of the coefficient on era were analyzed. The hybrids were clustered based on the coefficient of seedling drought tolerance from 1970s. The result indicated that drought stress influenced biomass significantly. The seedling drought tolerance increased from 1950s to 1960s and declined from 1960s to 1970s and afterwards. The single hybrids after 1970s were clustered into three groups. Six hybrids were most tolerant to seedling drought including Ludan 50, Nongda 108, Qundan 105, Yedan 13, Yedan 4, and Zhengdan 2. Nongda 60, Nongda 3138, and Shendan 16 had the worst tolerance. Therefore, the next task of maize breeding is to strengthen drought stress pressure in selecting inbred lines, which will establish a foundation for breeding the hybrids tolerant to drought.
      Tillering Characteristics of Multi-tiller Maize and Influence of Plant Density and Sowing Date
      WANG Ru-Fang, ZHANG Ji-Wang, Lü Peng,DONG Shu-Ting, LIU Peng, ZHAO Bin
      Acta Agron Sin. 2012, 38(02):  322-332.  doi:10.3724/SP.J.1006.2012.00322
      Abstract ( 1931 )   PDF (295KB) ( 1003 )   Save
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      Different maize varieties were used to study the tillering characteristics and regulations of multi-tiller maize under different plant densities and sowing dates. The results showed that tillers were co-elongated with leaves of main stem, the number of primary tiller (n) and leaf age of main stem (N) had the relationship of n = N-3, the secondary tillering had the same relationship as the primary one. Tillering ability showed significant differences among different maize varieties, Mexican’s tillering ability was the strongest, the maximum tiller number was about 25-40, and Keduo 4 was about 2-4 and then Wuyue 97-1 was about 1-2, however, Zhengdan 958 had no tiller in general. The tillering ability of maize could be affected by sowing date and plant density. Higher temperature and sunlight and lower plant density were favorable to tiller’s development. With the postponement of sowing date, the interval from seeding to tillering became shorter, the growth of tiller’s leaves became quicker, and the maximum tiller number was increased. When sowed on 25 April and 25 June at 45 000 plant ha-1 population, the maximum tiller number of the Keduo 4 was 3.50 and 4.00 while the ultimately tiller number was 2.33 and 2.00, respectively, so the eliminating rate of tiller was 33.4% and 50.0% respectively. The similar changes were observed in 30 000 and 60 000 plant ha-1 populations. With the increment of plant density, tiller’s occurrence was postponed, and the leaf ages decreased on same day after emergence of seedling, tiller number of main stem with the same leaf age and the maximum and ultimately numbers reduced, the tillers’ eliminating rate increased. When sowed on 25 April, taken the 30 000, 45 000, and 60 000 plant ha-1 populations, the maximum tiller number was 3.80, 3.50, and 3.22, and ultimately tiller number was 3.00, 2.33 and 1.67, so the eliminating rate was 21.05%, 33.43%, and 48.14%, respectively. The changes were similar when sowed at 25 June.
      TILLAGE & CULTIVATION·PHYSIOLOGY & BIOCHEMISTRY
      Effect of Wheat/Maize/Soybean and Wheat/Maize/Sweet Potato Relay Strip Intercropping on Bacterial Community Diversity of Rhizosphere Soil and Nitrogen Uptake of Crops
      YONG Ta-Wen, YANG Wen-Yu, XIANG Da-Bing, ZHU Zhen-Ying
      Acta Agron Sin. 2012, 38(02):  333-343.  doi:10.3724/SP.J.1006.2012.00333
      Abstract ( 2093 )   PDF (9660KB) ( 992 )   Save
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      The aim of this study was to understand the relationship between diversity of rhizosphere bacterial community and nitrogen uptake of crops in two relay strip intercropping systems: wheat/maize/soybean and wheat/maize/sweet potato. We analyzed the diversities of rhizosphere bacterial community in five cropping systems using denaturing gradient gel electrophoresis (DGGE) based on 16S rDNA. The cropping systems included wheat-soybean (A1), wheat-sweet potato (A2), maize single cropping (A3), wheat/maize/soybean (A4), and wheat/maize/sweet potato (A5). Compared to the sole cropping systems (A1, A2, and A3 treatments), the A4 treatment showed increases in grain nitrogen uptake and total nitrogen uptake amounts of aboveground of crops at both flowering (or silking) and maturity stages, and the Shannon-Weiner indices for rhizosphere bacterial community diversity was also increased significantly. The values of nitrogen uptake and the Shannon-weiner index in the relay strip intercropping systems were greater than those in sole cropping systems, and the values in the treatment with soybean stubble were greater than those in the treatment with sweet potato stubble. The number and strength of the DNA bands from DGGE profiles varied with the cropping systems, especially for the distinguished bands. The comparability of rhizosphere bacterial community composition was low among different cropping systems. The similarity coefficient (Cs) was higher between two relay strip intercropping systems than between relay strip intercropping system and sole cropping system, but the Cs value was low between A4 and A5 treatments. However, there was obvious difference of rhizosphere bacterial community composition between A4 and A5 treatments, and the A4 treatment was propitious to enhancing rhizosphere bacterial community diversity and increasing nitrogen uptakes of crops.
      Effect of Continuous Aeration on Growth and Activity of Enzymes Related to Nitrogen Metabolism of Different Rice Genotypes at Tillering Stage
      ZHAO Feng, ZHANG Wei-Jian, ZHANG Xiu-Fu, WANG Dan-Yang, XU Chun-Mei
      Acta Agron Sin. 2012, 38(02):  344-351.  doi:10.3724/SP.J.1006.2012.00344
      Abstract ( 1855 )   PDF (457KB) ( 1108 )   Save
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      In order to clarify the role of oxygen in the growth and development of rice and its mechanism of nitrogen, three rice genotypes, i.e., “Guodao 1” (indica), “Xiushui 09” (japonica), and “Brazilian upland rice” (upland rice), were cultured in nutrient solution with continuous aeration to measure the growth-related parameters and the activity of enzymes related to nitrogen metabolism at tillering stage. The results showed that, compared with the control, lower chlorophyll content in leaves was found in all the genotypes. The dry weights of shoots and roots were decreased by 44% and 40% for “Guodao 1” under continuous aeration, respectively, whereas no significant effects were observed for the “Brazilian upland rice” and “Xiushui 09”. The root length, specific surface area, and the intensity of α-naphthylamine oxidation of roots were increased significantly by continuous aeration, irrespective of the genotypes. The nitrogen accumulation in the “Guodao 1” and “Brazilian upland rice” under aeration was reduced by 35.8% and 36%, respectively. Therefore, the nitrate reductase activity (NRA) in leaves was significantly increased, while the glutamine synthetase activity (GSA) was decreased under aeration. The NRA in leaves of “Xiushui 09” under continuous aeration tended to increase (P > 0.05) in comparison to the control. Thus, continuous aeration could increase the surface area and oxidation intensity in rice roots, and reduce the chlorophyll content and GSA in rice leaves, which may reduce nitrogen absorption and dry matter accumulation. In addition, these were significant differences in responses of rice genotypes to continuous aeration.
      Effects of PASP-KT-NAA on Photosynthesis and Antioxidant Enzyme Activities of Maize Seedlings under Low Temperature Stress
      XU Tian-Jun, DONG Zhi-Jiang, LAN Hong-Liang, FEI Zhi-Chao, GAO Jiao, JIE Zhen-Xin
      Acta Agron Sin. 2012, 38(02):  352-359.  doi:10.3724/SP.J.1006.2012.00352
      Abstract ( 1884 )   PDF (353KB) ( 1338 )   Save
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      A pet experiment of maize seedlings was conducted to investigate the effects of low temperature stress and the chemical regulator of PASP-KT-NAA (PKN) on photosynthetic, physiological parameters, chlorophyll contents, and various antioxidant enzymes activities. The results showed that, in maize seedlings under low temperature stress the photosynthesis ability and SOD, POD, CAT activities reduced; the formation speed of hydrogen peroxide and superoxide anion, as well as MDA contents increased. PKN pretreatment increased Pn, Gs, Fv/Fm, and chlorophyll contents. Under low temperature stress for seven days, Pn, Gs, Fv/Fm, chlorophyll contents of ZDTR and FDTR were higher than those of CK, which was increased by 88.95% and 61.11%, 593.33% and 1 741.67%, 111.50% and 145.16%, 36.61% and 54.03%. While the formation speed of hydrogen peroxide and superoxide anion reduced, MDA contents decreased too. Simultaneously, SOD, POD, CAT activities were increased by 292.59% and 632.98%, 295.07% and 360.54%, 254.55% and 265.45%. In conclusion, PKN pretreatment can improve the cold resistance of maize seedlings
      RESEARCH NOTES
      Cloning and Expression Analysis of GmMYB Induced by Abiotic Stresses
      SUN Xia, LIU Jin-Ti, YUAN Xiao-Hui, BO Xiang-Wen, DU Wei-An, LIN Hai-Xiang, MA Yong-Bei, Jun ABE, QIU Li-Juan, LIU Bao-Hui
      Acta Agron Sin. 2012, 38(02):  360-368.  doi:10.3724/SP.J.1006.2012.00333
      Abstract ( 1966 )   PDF (363KB) ( 1130 )   Save
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      Response to external environment is the outcome of stress-induced gene expression. In this paper, based on one stress-induced EST sequence, we cloned four R2R3-MYB genes from soybean cultivar Dongnong 42, whose genomic sequences consisted of three exons and two introns. Three of them corresponding to Gm02g1300, Gm03g38040, and Gm10g01340 are respectively consistent with the sequences of Willams 82. A mutation at the 375th single nucleotide in the sequence of Gm19g40650 from Dongnong 42 caused a synonymous amino acid substitution (E125–D125). To test the relationship of four MYB genes with stress resistance, we treated the seedlings of cultivar Dongnong 42 with abiotic stresses including salt, alkali, drought and low temperature in the artificial climate chamber. Quantitative PCR analysis indicated that all of the four genes were transient down-regulated or up-regulated when subjected to the stresses, but different in the expression time, level and tendency. Gm02g01300 was induced by drought stress while Gm03g38040 was strongly induced by multiple stresses, indicating that they play important roles in responding to external stresses. There were also differences in the expression of individual gene between cotyledons and embryos. These results under a variety of abiotic stress conditions suggest that the four R2R3-MYB genes are different not only in the expression patterns, but also in the regulation modes.
      Resistance QTL Mapping Aanalysis for Storage Pest Sitophilus zeamais in Wheat
      CHEN Zhen-Hong, LI Dun, WEI Hui-Ting, LIU E-Xi, LI Chao-Su, DENG Mei, LI Cheng-Qiong, WANG Ji-Rui, WEI Yo-Meng, YANG Wu-Yun, ZHENG Wei-Liang
      Acta Agron Sin. 2012, 38(02):  369-373.  doi:10.3724/SP.J.1006.2012.00369
      Abstract ( 1964 )   PDF (231KB) ( 971 )   Save
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      Quantitative trait loci (QTLs) associated with Sitophilus zeamais resistance were identified using a population (127 recombined inbred lines) from wheat cross Chuannong 16×Chuanmai 42. In a stimulated storage environment, adult, larva, and egg of S. zeamais were artificially fed with wheat seeds harvested in 2008 and 2009, respectively. Five QTLs located on chromosomes 3B, 2D, 3D, and 4B were detected with phenotypic contributions of 10.2%, 8.5%, 8.3%, 8.5%, and 11.3%, respectively. The QTLs located between Xbarc6 and Xgwm112 on chromosome 3D were identified in seeds from both growing years, which explained 8.3–8.5% of the phenotypic variance. The positive allele on this locus was from parent Chuannong 16.
      Color Region Classification of Flue-cured Tobacco Leaves Based on the Image
      BO Chi-Li, QI Meng, WEI Chun-Yang, LI Feng, ZHANG Shi-Xiang, WANG Jian-Wei, GUO Wei-Min, AI Zhi-Lu
      Acta Agron Sin. 2012, 38(02):  374-379.  doi:10.3724/SP.J.1006.2012.00374
      Abstract ( 1786 )   PDF (251KB) ( 1206 )   Save
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      Leaf color is an important indicator of flue-cured tobacco quality; however, there is a big difference among similar color tobacco leaves from different areas. Color features of tobacco leaves were obtained by using Region Growing Method in the pre-processing, and then made region classification by using Support Vector Machine (SVM). The results showed that in the case of small samples, radial basis function was the kernel function of the SVM, and the appropriate model parameters were determined. The classification accuracies for training set and test set of the SVM model were 100% and 86.67%, showing that SVM has a perfect performance in color region classification of tobacco leaves.

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
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E-mail: cropjournal@caas.cn
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