Loading...
Welcome to Acta Agronomica Sinica,

Table of Content

    12 January 2007, Volume 33 Issue 01
    • ORIGINAL PAPERS
      Genetic Analysis and Chromosomal Location of Two New Genes for Resistance to Powdery Mildew in Wheat (Triticum aestivum L.)
      MA Qiang;LUO Pei-Gao;REN Zheng-Long;JIANG Hua-Ren;YANG Zu-Jun
      Acta Agron Sin. 2007, 33(01):  1-8. 
      Abstract ( 2585 )   PDF (1473KB) ( 2158 )   Save
      Related Articles | Metrics

      Powdery mildew, caused by Erysiphe graminis f. sp. tritici, is a major wheat (Triticum aestivum L. em Thell) disease in the world. The use of resistant cultivars is the most economical, effective and environmentally safe way to control this disease. A new wheat line YU25, which derived from a wide cross between a wheat cultivar CM107 and octoploid Trititrigia TAI7047 (Taiyuan 768/ Elytrigia intermedium//76(64)), exhibit immune to wheat powdery mildew. In the present study, for genetic analysis of its resistance to powdery mildew, the line YU25 was crossed with a susceptive wheat cultivar Mianyang 11 (MY11) and backcrossed both with MY11 and YU25 to produce their F1 (25 individuals), F2 (352 individuals), BC1F1 (55 individuals) and BC2F1 (80 individuals) populations, which were grown in greenhouse and inoculated by the epidemic predominant race of powdery mildew in Southwest China. The response patterns of F2 population showed that the I (immune):R (resistant):S (susceptible) segregation ratio closely fit to 12:3:1, suggesting that the wheat line YU25 carried two different dominant resistance genes to powdery mildew, one of them exhibited immune and the other showed highly resistant. The results was also supported by the 2:1:1 segregation ratio of I:R:S in the BC1F1 population. F2 population consisting of 221 individuals was screened with 294 wheat microsatellite primer pairs to detect molecular markers linked to genes responsible for powdery mildew resistance. The results indicated that the microsatellite marker Xgwm297-7B on chromosomal arm 7BS and Xgwm210-2D on chromosomal arm 2DL were linked with the immune gene and highly resistant gene to wheat powdery mildew, with the genetic distance 13.0 cM and 16.6 cM, respectively. So far, there is no reported resistant gene to powdery mildew on chromosome arm both 7BS and 2DL. Moreover, there are also no genes conferring resistance to wheat powdery mildew with the origin of E. intermedium. Hence, pedigree analysis of YU25 and chromosomal location of the genes afforded a persuasive evidence to support the conclusion that the immune gene and highly resistant gene in YU25 derived from E. intermedium, are new genes for resistance to powdery mildew in wheat and are temporarily designated PmE and PmYU25, respectively. It could play an important role in wheat breeding programs for powdery mildew resistance. The application value of the line YU25 in wheat breeding, which should contain double translocation between wheat and E. intermedium chromosomes, was discussed in this paper.

      Chromosome Location and Linkage Analysis of a Few Agronomical Important Traits in Foxtail Millet
      WANG Run-Qi;GAO Jun-Hua;GUAN Zhong-Bo;MAO Li-Ping
      Acta Agron Sin. 2007, 33(01):  9-14. 
      Abstract ( 2176 )   PDF (441KB) ( 1075 )   Save
      Related Articles | Metrics

      Foxtail millet [Setaria italica (L.) Beauv.] is a kind of millet crops, its genetic research is relatively laggard as compared with other cereals such as maize, rice and wheat. Chromosome gene location analyses of agronomical important traits are rarely reported. Some basic knowledge about genes controlling important characteristics are important to improve breeding program. Our research group established a complete set of primary trisomic of foxtail millet in 1993, and began to conduct chromosome gene location by using the system in 1994. So far, we have identified that the waxy endosperm gene is located on chromosome 4, dwarf gene of An’ai 3 on chromosome 3, red glume gene and bristle gene on chromosome 1 and 2, the male-sterile gene of line 1066A and yellow seedling gene on chromosome 6 and 7 respectively. This research still conducted the chromosome gene location of foxtail millet by trisomic analysis. Crosses were made by using Yugu 1 primary trisomic series 1–7 and tetrasomics 8, 9 as female parents, dominant dwarf, Fagu 56-81 and Maqingmiao as male parents, so as to identify the locations of dominant dwarf gene, white millet gene and grey millet gene. Each F1 plant was identified according to plant morphological characteristics of primary trisomic series 1–7 and labeling traits of male parent; the trisomics 8, 9 of F1 plants were identified by checking chromosome number of plant root tip cells. Through investigating and analyzing the segregation of F2 populations, the dominant dwarf gene was located on chromosome 3, white millet gene on chromosome 4, grey millet gene on chromosome 6. Allelic test for 9 grey foxtail millet varieties obtained from different regions showed that these grey millet lins are all allele. Gene linkage analysis were carried out by using the segregating populations derived from cross combinations of 1066A×Fagu56-81 and 1066A×Maqingmiaoto. As a result, the exchange value between the waxy endosperm gene and white millet gene on chromosome 4 was (28.9±4.4) cM; and the exchange value between the sterile gene of 1066A and cyan-millet on chromosome 6 was (23.2±1.8) cM.

      Polymorphism Analysis of HMW-GS in Chinese Endemic Wheat Landraces, Spelt and Club Wheat
      DU Jin-Kun;YANG Xin-Quan;ZHANG Yi-Rong;NI Zhong-Fu;SUN Qi-Xin
      Acta Agron Sin. 2007, 33(01):  15-19. 
      Abstract ( 2020 )   PDF (560KB) ( 1073 )   Save
      Related Articles | Metrics

      High molecular wight glutenin subunits(HMW-GS) are important element of wheat storage proteins, they play a key role in determining bread making quality. Also they can be used to study the origin, evolution and genetic differentiation of hexaploid wheat. In this study, we explored the composition of HMW-GS of three Chinese endemic wheat landraces (T. petropavlavskyi, T. tibetanum, T. yunnanense). Combining the result with some previous research, we analysed the polymorphism of HMW-GS in these three landraces, common wheat, spelt and club wheat. It was found that the composition of HMW-GS in spelt has its unique character: (1) the subunit 1 on Glu-A1 is predominant in spelt; (2) subunits 13+16 on Glu-B1 is predominant in spelt but unfrequent in other hexaploid wheat. Some special types of HMW-GS were found in the accessions of T. petropavlavskyi, which were rarely found or never be reported in other hexaploid wheat (including Aegilops tauschii). It is concluded that the common wheat is the possible provider of the cytoplasm of T. petropavlavskyi and the origin of the nucleolus genome of T. petropavlavskyi is very complicated, and maybe from Polish wheat, common wheat and Aegilops tauschii originated in Xinjiang Province, and its evolution routine needs to be more closely studied in the future.

      Breeding and Blast Resistance Identification of Lijiangxintuanheigu Near-isogenic Pyramid Lines
      LIU Xin-Zhan;ZHAO Ming-Fu;HE Yue-Qiu;CHEN Da-Zhou;XIAO Ye-Qing;LEI Cai-Lin
      Acta Agron Sin. 2007, 33(01):  20-24. 
      Abstract ( 2123 )   PDF (366KB) ( 1038 )   Save
      Related Articles | Metrics

      Rice blast is one of the most widespread and devastating diseases worldwide. Pyramiding more rice blast resistance gene into one rice variety is economic and effective approach for improvement of rice variety with durable resistance to blast. It can slow the directional evolution of Magnaporthe grisea and prolong the service life of resistance variety. In this study, three F6 recombinant inbred populations were made using Lijiangxintuanheigu (LTH) near-isogenic lines (NILs) as parents. By means of resistance test with differential isolates, five pyramid lines carrying two resistance genes were obtained: 1) F-Kpib-3 and F-Kpib-6 for resistance genes Pi-kp/Pi-b; 2) F-Kita2-7 and F-Kita2-9 for Pi-k/Pi-ta2 and 3) F-Kmita for Pi-km/Pi-ta. The lines with the same gene combination had the same resistance reactions and higher resistance frequencies than the LTH NILs. The resistance frequencies were 100.0%, 91.7% and 50.0% for the above three groups, respectively. And also their disease scores were lower than the LTH NILs’. This implies that gene pyramiding could increase the spectrum and the strength of resistance to blast pathogen. The pyramiding genes are a simply additive relationship. The pyramid lines with LTH background may be used for identifying pathogenic types and monitoring variation directions of M. grisea in the field and used as resistant parents for blast resistance breeding of rice.

      Detection of QTL Associated with Rice Stripe Resistance in Cultivar IR24
      SUN Dai-Zhen;JIANG Ling;ZHANG Ying-Xin;CHENG Xia-Nian;ZHAI Hu-Qu;WAN Jian-Min
      Acta Agron Sin. 2007, 33(01):  25-30. 
      Abstract ( 1995 )   PDF (443KB) ( 1034 )   Save
      Related Articles | Metrics

      In order to verify the quantitative trait loci for rice stripe in rice cultivar IR24, QTL mapping of resistance to rice stripe was studied using both recombinant inbred lines (RIL) and a series of IR24 chromosome segment substitution lines (CSSLs) with Asominori genetic background. Four QTL were detected and located on chromosome 3, 5, 7,11, respectively, (qSTV3, qSTV5, qSTV7, qSTV11) using RIL population by natural condition test in the infected rice field. The positive resistance effects at qSTV3, qSTV7 and qSTV11 were from IR24. A graphical genotype analysis of the CSSL population indicated that the IR24-derived segments presented in five lines with QTL conferring rice stripe resistance. Comparing RIL with CSSL linkage maps, we found that the marker regions of qSTV3, qSTV7 and qSTV11 coincided with IR24 segment in CSSL17, heterozygous segment in CSSL4 and IR24 segment in CSSL39, and IR24 segment in CSSL61 and heterozygous segment in CSSL62, respectively. Additionally, qSTV3 was arranged on a gene cluster of chromosome 3 associated with sucking insect resistance, suggesting it be a new and stable expression locus, and qSTV7 be another new QTL detected in this research, after comparing with previous reports. These results indicated that IR24 carried several new resistance genes controlling rice stripe. This will provide a new resistance resource for avoiding genetic vulnerability from single resistance gene, Stvb-i, and provide a foundation for breeding rice varieties with stable resistance to rice stripe by diversifying rice stripe virus and small brown planthopper resistance genes in MAS.

      Effects of Cultivation Methods on Grain Quality in Upland Rice cv. Zhonghan 3 and Paddy Rice cv. Wuxiangjing 99-8

      ZHANG Ya-Jie;ZHOU Yu-Ran;SUN Bin;DIAO Guang-Hua;LIN Qiang-Sen;YANG Jian-Chang

      Acta Agron Sin. 2007, 33(01):  31-37. 
      Abstract ( 2055 )   PDF (548KB) ( 1038 )   Save
      Related Articles | Metrics

      Upland rice and dry-cultivated paddy rice have been attracted more and more attention because of limited water resources in China, however, there is little information available on effect of cultivation methods on grain quality of upland rice and paddy rice. The objective of this study was to evaluate the difference between upland rice cultivar Zhonghan 3 (japonica) and paddy rice cultivar Wuxiangjing 99-8 (japonica) under three cultivation methods of moist cultivation (MC, control), plastic film mulching cultivation (PFMC) and bare cultivation (BC). The results showed that, compared with the MC, the grain yield was significantly lower under PFMC for upland rice, but no significant difference between PFMC and MC for paddy rice, and significantly reduced under BC for both upland and paddy rice. The chalkiness, the ratio of kernel length to kernel width, amylose content, gel consistency and peak viscosity were lower, whereas protein content and pasting temperature were higher for PFMC and BC rice compared with those of MC rice. The percentage of chalky grains was significantly decreased under PFMC and BC for upland rice and under BC for paddy rice, but no significant difference between PFMC and MC for paddy rice. Chalkiness, amylose content, gel consistency, breakdown viscosity and the declining amount of nitrogen content in plants from heading to maturing stages were the least and protein content and setback viscosity were the most and Q-enzyme average activity remained the highest level for PFMC among the three cultivation methods. Compared with paddy rice, upland rice showed lower percentage of chalky grains and gel consistency, no difference in chalkiness, and higher levels in ratio of kernel length to kernel width, amylose content, protein content and pasting temperature. The relationship between Q-enzyme activity and grain quality was similar to that between the grain-filling parameters from Richards equation. The results suggest that the dry cultivation can improve appearance quality and nutrient quality, whereas has negative effects on cooking quality.

      Effect of High Air Temperature during Different Growth Stage on Starch Synthesis in Grain and Yield in Maize (Zea mays L.)
      ZHANG Bao-Ren;DONG Shu-Ting;HU Chang-Hao;WANG Kong-Jun
      Acta Agron Sin. 2007, 33(01):  38-42. 
      Abstract ( 1851 )   PDF (411KB) ( 1129 )   Save
      Related Articles | Metrics

      The global climate is getting warmer and warmer with the wide use of chemical and petroleum fuels. The experiment was conducted using maize cultivars Nongda 108 and Shannong 3 with the treatments of increased air temperature at three different growing stages in growth-chamber set up in the field condition, and the yield, the content of starch and the activities of the key enzymes in starch synthesis of maize kernels were determined. The results indicated that the first high air temperature treatment at the first stage (0–28 days after the emergence of seedling) had almost no effect on grain yield, the second one (29–57 days after the emergence of seedling) and the third one (58–86 days after the emergence of seedling) decreased the yield in maize significantly. Among them, the second one had a sharp decrease in yield, by 23.8% on an average. Meanwhile, high air temperature treatment also decreased the activities of fruictose-1,6-diphosphatase (FBPase), sucrose phosphate synthase (SPS), starch synthase (SS) and adenosine diphosphate glucose pyrophosrylase (ADPGPPase), and with the largest decrease in the second high temperature stage. As to the starch content in grains, there were no influence of high air temperature treatment at the 1st stage, and negative influence of high air temperature treatment at the 2nd and 3rd stages. Postponing sowing date and selecting heat-resistant cultivars were suggested to relieve the influence of high air temperature on maize.

      Main Index of Source and Sink in Nitrogen Use Efficiency for Grain Output in Conventional Indica Rice Cultivars
      DONG Gui-Chun; WANG Yu-Long; ZHANG Yue-Fang; CHEN Pei-Feng; YANG Lian-Xin and HUANG Jian-Ye
      Acta Agron Sin. 2007, 33(01):  43-49. 
      Abstract ( 1820 )   PDF (541KB) ( 1176 )   Save
      Related Articles | Metrics

      Improving nitrogen use efficiency in crops is of great importance both in crop production and environmental protection. Genetically improving crop varieties so as to make full use of the potentials in nitrogen uptake and utilization has been considered as one of the most economical and effective ways to enhance nitrogen use efficiency in crops. Nitrogen use efficiency depends on the ability of nitrogen uptake and utilization in rice plant. Many studies have shown that there exist genotypic differences in nitrogen use efficiency for biomass and grain production in rice. Yet, little information in the characteristics of yield components, biomass production and allocation, nitrogen uptake and allocation, characteristics of source and sink, and structure of root system in rice varieties with higher nitrogen use efficiency has been reported. In this study, 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Leaf area index (LAI), sink potential, dry matter weight and nitrogen content of different organs were measured. The tested rice cultivars were clustered into 6 types (i.e. A, B, C, D, E and F,A was lowest, F was highest) based on their nitrogen use efficiency for grain output (NUEg) level by the MinSSw method, to study the difference of indexes of source and sink and find out the key one from them in conventional indica rice with different types of NUEg. Results showed that the difference of NUEg in conventional indica rice cultivars used in this study was very large, the average NUEg of A, B, C, D, E and F were 20.51, 31.04, 35.64, 39.46, 43.55 and 50.92 g grain g-1N in 2001, and 24.33, 31.61, 35.83, 39.06, 43.51, 50.00 g grain g-1N in 2002, respectively; the basic characteristics of conventional indica rice cultivars with higher NUEg were that LAI at heading stage was small and decrease of LAI during the grain-filling stage was slow, while net assimilation rate was high, sink potential was large, sink potential per unit leaf area , sink potential per unit dry matter weight and sink potential per unit N at heading stage were high. Multiple stepwise regression analysis showed that NUEg was significantly influenced by sink potential per unit N, sink potential per unit dry matter weight, grain yield per unit sink potential, LAI at heading stage and decrease of LAI from heading to mature stage, and the determination coefficient ranged from 0.797–0.854. Path analysis showed that effects of sink potential per unit N, sink potential per unit dry matter weight and grain yield per unit sink potential on NUEg were larger than those of LAI at heading stage and decrease of LAI during the grain-filling stage.

      Correlation Analysis and QTL Mapping of Grain Shape and Grain Weight in Rice under Upland and Lowland Environments
      GUO Yong-Mei;MU Ping;LIU Jia-Fu;LI Zi-Chao;LU Yi-Xuan
      Acta Agron Sin. 2007, 33(01):  50-56. 
      Abstract ( 1990 )   PDF (462KB) ( 1121 )   Save
      Related Articles | Metrics

      Grain length (GL), grain width (GW), length width ratio (LWR) and grain weight(GWt) are most important apparent quality traits in rice, which are positively correlated with the commercial value of rice especially in international market. Moreover, grain shape is also a vital factor related to rice yield and milling quality. Companed with GL, GW and LWR, grain weight is one of the most important components related to rice yield. Several studies reported that GL, GW, LWR and GWt were controlled by some QTLs were detected under lowland condition. There have been no reports about QTLs for grain shape and grain weight under both upland and lowland conditions. Therefore, it is necessary to analyze the correlation and inheritance of grain shape and grain weight between under upland and under lowland conditions, especially to find QTLs under upland condition.
      A doubled haploid (DH) population consisting of 116 DH lines developed through anther culture of the F1 hybrid between an upland rice cultivar ‘IRAT109’ and a lowland rice cultivar ‘Yuefu’ was used in this study. The parents and the 116 DH lines were planted under water- and dry-cultivation conditions, on the experiment farm of China Agricultural University in 2002. Seeds of parents and 116 DH lines were harvested at maturity, and used to measure grain length, grain width, length width ratio and grain weight. QTLs analysis was conducted with QTL Mapper version 1.0 and the constructed molecular linkage map consisting of 165 molecular markers, which covered 1 535 cM in length with an average distance of 9.3 cM between adjacent markers. A threshold probability of P<0.005 was used to declare the existence of additive QTLs. Correlation analysis between grain shape and grain weight was conducted using the software of SPSS.
      Positively significant correlations between GL and LWR and between GL and GWt in both upland and lowland environments were observed. Negatively significant correlations between GW and LWR and positively significant correlations between GW and GWt under the two environments were also detected. This result indicated that GL, GW, LWR and GWt had closely genetic background. All the four traits in upland environment were significantly correlated with those in lowland environment respectively, with the biggest correlation coefficient of 0.817 for GL and the smallest coefficient of 0.457 for GW. Therefore, compared to GW, GL was less affected by water stress (upland condition).
      A total of 14 QTLs were detected for GL, GW, LWR and GWt, which located on chromosome 1, 5, 6, 7,10 and 12. Ten QTLs had high general contribution with explained variance of over 10%. For GL, one QTLs under upland condition and four QTLs under lowland condition were detected respectively. These QTLs explained 5.97%–28.85% of phenotypic variance. The LOD score was 1.93–5.11. For GW, only one QTLs was detected under upland condition. The LOD score and general contribution was 2.39 and 12.76% respectively. For LWR, one QTLs under upland condition and two QTLs under lowland condition was detected respectively. These QTLs explained 7.78%–21.89% of phenotypic variance. The LOD score was 2.08–4.60. For GWt, there were two additive QTLs under upland condition and three additive QTLs under lowland condition respectively. They explained 4.1%–14.8% of phenotypic variance. The LOD score was 2.68–9.45. Three QTLs qGL-5, qGWt-1a and qGWt-1b were both detected under upland and lowland environments (common QTL). Two co-localized QTLs (qGL-1a and qGWt-1a, and qGL-1b and qGWt-1b) controlling GL and GW were detected. These QTLs would be helpful in MAS of grain shape breeding.

      Effects of Nitrogen Application on Nitrogen Accumulation and Translocation as well as Their Heterosis in Different Organs of Hybrid Wheat
      ZHAO Wan-Chun;DONG Jian;GAO Xiang;ZHANG Gai-Sheng
      Acta Agron Sin. 2007, 33(01):  57-62. 
      Abstract ( 1986 )   PDF (476KB) ( 993 )   Save
      Related Articles | Metrics

      Nitrogen fertilizer is one of the most important factors to influence the nitrogen metabolism in different organs as well as the growth and development of wheat. In this study, six hybrids of wheat (Triticum aestivum L.) and their seven parents were employed to compare the nitrogen accumulation and translocation in different organs at various growth stages and further to study the heterosis of nitrogen utilization. The experiment was set by a split plot design with two replications under two levels of nitrogen applications 0 and 200 kg ha-1. Above-ground plant parts were harvested at 75, 90, 105, 120, 140 and 160 d after sowing, corresponding with stages of stem elongation, flag leave emergence, heading, flowering, milk-ripe and maturity, respectively. The samples were partitioned into leaf, stem and sheath, stalk and chaff of spike, and grain, then microwaved for 4 min, and dried in an oven at 60℃. Nitrogen content of the hammermill-ground sample and grain nitrogen content were determined by near infrared reflectance spectrometry. The results showed that the nitrogen application significantly increased the amount of nitrogen accumulation and content of various organs, but didn’t affect their change patterns. Leaves were the main nitrogen storage organ prior to anthesis while grains stored the largest amount of nitrogen post anthesis, followed by stem and sheath. Nitrogen application had no significant effects on the heterosis of nitrogen accumulation, but had a significant inhibitory effect on the heterosis of nitrogen content. With nitrogen application nitrogen translocation was greatly accelerated in leaves, but not in stems and sheaths, stalk and chaff of spikes. More than 90% of nitrogen translocation of total straw came from leaves. The contributions to nitrogen translocation efficiency and contribution ratio in all organs were the largest in leaves, the next in stalk and chaff of spikes, and there was no significant difference in the same organ whether nitrogen was applied or not. There was a positive heterosis in nitrogen translocation, translocation efficiency and contribution ratio of various organs when no nitrogen was applied, but a negative heterosis when nitrogen was applied, which indicates an inhibitory effect of nitrogen application on the heterosis of nitrogen translocation.

      Isolation and Characterization of High-Molecular-Weight Glutenin Subunit Genes in Agropyron cristatum
      LI Shao-Fang;ZHOU Huan-Bin;LI Li-Hui;WANG Xian-Ping;ZHANG Xiang-Qi
      Acta Agron Sin. 2007, 33(01):  63-69. 
      Abstract ( 2121 )   PDF (962KB) ( 1036 )   Save
      Related Articles | Metrics

      Wheat processing quality is closely correlated with composition and quantity of gluten proteins, in particular with high-molecular-weight glutenin subunits (HMW-GS) encoded by the Glu-1 loci (Glu-A1, Glu-B1 and Glu-D1). In the related species of wheat, there are abundant HMW-GS alleles which are possibly valuable genetic resource for improvement of the wheat processing quality. Agropyron is a closely related genus to wheat and some species in it have been successfully crossed with common wheat and used for variety improvement. However, the HMW-GS in Agropyron was rarely studied. In the present study, SDS-PAGE and PCR methods were used to study the composition and the coding genes of HMW-GS in diploid (PP), tetraploid (PPPP) and hexaploid (PPPPPP) A. cristatum (L.) Gaertn. The results of SDS-PAGE indicated that the composition of HMW-GS varied not only in different ploidy types (2x, 4x and 6x) but also in different seeds belonging to the same ploidy type since Agropyron cristatum is a cross-pollinated species. There were two expressed HMW-GS totally in each ploidy type. The molecular weigh (MW) of all the subunits in the three types of A. cristatum with different ploidy levels was smaller than that in Chinese Spring. As results of PCR, three y-type HMW-GS genes named as Bty1, Bty2 and Bty3 were isolated from diploid A. cristatum with the length of 1 227 bp, 1 350 bp and 1 530 bp, respectively. One y-type gene named Bfy1 was isolated from tetraploid A. cristatum with the length of 1 227 bp. And three y-type genes named Bsy1, Bsy2 and Bsy3 were isolated from hexaploid A. cristatum, with the length of 1 227 bp, 1 530 bp and 1 896 bp, respectively. The sequence comparison showed that the homologous relationship of the seven genes was very close. When the ORFs of the seven genes were analyzed, it showed that only Bsy2 in hexaploid A. cristatum possessed an ORF which encoded a protein consisting of 487 amino acid residues with an estimated MW of 53 kD which was similar with the MW of the larger HMW-GS in SDS-PAGE pattern. The nonsense mutations of C to T or G to A in the repetitive domains of the other six genes silenced them all. The mutation of C to T was the main type of nonsense mutation occurring in HMW-Gs genes of A. cristatum, just as occurring in wheat. The amino acid sequences analysis indicated that the sequences of N-terminal, C-terminal and repetitive domain of the seven subunits were similar to the y-type subunits in wheat. But some differences were also found, such as a decapeptide deletion in subunit Bty2, no irregular tripeptide in subunits Bty1, Bty2, Bfy1 and Bsy1, an extra Cys in the repetitive domain of unexpressed subunits of Bty3 and Bsy3, etc. Finally, the evolutional relationship of the seven subunits was analyzed using Neighbor-Joining tree and the results showed that Bty1, Bfy1 and Bsy1 were most close to each other and secondarily close to Bty2, Bty3 and Bsy2 were close to Ey subunit in Elytrigia elongata, and Bsy was close to Dy10 and Dy12 subunits in common wheat. The N-terminal of the seven subunits was close to the y-type subunits in wheat, and the C-terminal of the six subunits except Bsy3 was more close to the x-type subunits. It could be concluded that the six HMW-GS (Bty1, Bty2, Bty3, Bfy1, Bsy1 and Bsy2) in A. cristatum are not typical y-type HMW-GS subunits and they may represent an osculant subunits creating in evolution history.

      A Maximum Likelihood-Based Dynamic Clustering Method and Its Application
      XIAO Jing;HU Zhi-Qiu;WANG Xue-Feng;XU Chen-Wu
      Acta Agron Sin. 2007, 33(01):  70-76. 
      Abstract ( 1733 )   PDF (483KB) ( 1032 )   Save
      Related Articles | Metrics

      Clustering analysis is to determine the intrinsic grouping in a set of unlabeled data. A cluster is a collection of objects which are similar between them and are dissimilar to the objects belonging to other clusters. However, the current clustering techniques have not addressed all the requirements adequately. For instance, dealing with large number of dimensions and large number of data can be problematic because of time complexity. The effectiveness of the distance-based clustering methods depends on the definition of distance; if an obvious distance measure doesn’t exist we must define it, which is not always easy, especially in multi-dimensional spaces. In addition, the choice of the optimal number of clusters in practice is impossible. Thus, choosing the correct number of clusters and the best clustering method is still a question open to discussion. In order to solve these problems, in this paper, we introduced a maximum likelihood-based dynamic clustering method, which combined the conventional dynamic clustering and discrimination analysis. The parameters of different clusters were estimated by the maximum likelihood method implemented via expectation-maximization (EM) algorithm and the objects were classified by the Bayesian posterior probability. This classified idea could increase the posterior confidence of classified individuals. The results of simulation studies showed that the proposed method not only unbiasedly estimated the corresponding cluster parameters but also differentiated the optimum clustering numbers by Bayesian information criterion (BIC). Compared with the K-means method and the minimum square sum within groups (MinSSw) method, the proposed method was more robustness and had almost the same clustering accuracy as K-means and MinSSw methods. Moreover, the misclassified rate (MR) could be reduced by enhancing the discrimination criterion. However, the unclassified rate (UR) would be increased by enhancing the discrimination criterion. Thus, an eclectic discrimination criterion could be given by the user in order to decrease both MR and UR. The result indicated that the proposed method had a significant advantage on clustering accuracy compared to the K-means and MinSSw methods. An example of the plant height and the number of tiller of F2 population in rice cross Duonieai×Zhonghua 11 was used in the illustration. The results listed in Table 6 indicated that the genetic difference of these two traits in this cross involves only one pleiotropic major gene. The additive effect and dominance effect of the major gene were estimated as -24.57 cm and 57.12 cm on plant height, and 23.01 and -25.89 on number of tiller, respectively. The major gene shows overdominance for plant height and near complete dominance for number of tillers.

      Identification of Hybrid Rice and Prediction of Heterosis with Rim2 Superfamily Molecular Fingerprint
      ZHANG Li-Xia;WANG Lin-You; ZHANG Li-Hua;HE Zu-Hua; Jin Qing-Sheng;WANG Jian-Jun
      Acta Agron Sin. 2007, 33(01):  77-83. 
      Abstract ( 1893 )   PDF (1166KB) ( 1020 )   Save
      Related Articles | Metrics

      The rice Rim2 is a unique stress-induced transposon superfamily recently identified in Oryza genomes. The polymorphisms of Rim2 core region provide a novel technique to fingerprint rice genetic variation. In the past decade, DNA markers such as RAPD, AFLP, RFLP and SSR have been extensively used for fingerprinting and exploring the genetic diversity and evolutionary relation of rice genetic resources. In this paper, Rim2 elements were used as the DNA marker to fingerprint indica and japonica hybrid rice and to predict their heterosis according to the molecularly genetic distance. Five pairs of PCR primers based on the Rim2 sequences were selected to amplify cDNA of twenty-one indica and twenty japonica rice, including three sterile lines, nine restoring lines and nine hybrids in indica and three sterile lines, eight restoring lines and nine hybrids in japonica. A total of thirty-eight bands were obtained, of which twenty-six were polymorphic, accounting for 69.64%. The average polymorphism rate of japonica was 56.67%, which was apparently higher than that of indica. The dendrogram based on Nei’s distance showed that twenty-one indica rice and twenty japonica rice could be divided into six groups and seven groups respectively. The analysis of genetic relationship among materials showed that Rim2 molecular fingerprint could distinguish most of indica or japonica rice. Correlations were found in japonica rice between the genetic distance of parents and their hybrid heterosis, while not in indica rice. These findings demonstrate the potential of developing a more powerful molecular tool based on the tremendous variability of the Rim2 superfamily to explore on administration of seed production, variety licensing, marker-aid selection in breeding programs, such as RAPD, AFLP, RFLP and SSR have achieved.

      Activities of Enzymes Involved in Starch Synthesis and Starch Accumulation in Grains of Two Wheat Cultivars with a Different Amylose Content
      YAN Su-Hui;WANG Zhen-Lin;DAI Zhong-Min;LI Wen-Yang; FU Guo-Zhan;HE Min-Rong;YIN Yan-Ping
      Acta Agron Sin. 2007, 33(01):  84-89. 
      Abstract ( 2046 )   PDF (427KB) ( 1128 )   Save
      Related Articles | Metrics

      The amylose content of wheat grain is significantly correlated with amount of Waxy protein subunit. However, there is a great difference in amylose content among different wheat cultivars which all have three Waxy genes. In order to investigate the activity changes of enzymes involved in starch biosynthesis, the characteristics of starch accumulation in grains, and the relationship between them, two wheat (Triticum aestivum L.) cultivars, JM20 (lower amylose content in grains) and LM21 (higher amylose content in grains) were used in the study, which both carry three Waxy protein subunits. The results indicated that the activities of sucrose synthase (SS), adenosine diphosphorate glucose pyrophrylase (AGPP), soluble starch synthase (SSS), granule-bound starch synthase (GBSS) changed in the pattern of a single-peak curve during grain filling. The activities of SS, AGPP, GBSS, SSS and SBE in LM21, which had higher starch content, were higher than those in JM20. The accumulation rate of amylopectin was significantly or highly significantly correlated with the activities of SS, AGPP, SSS and SBE, and the accumulation rate of amylose was highly significantly correlated with the activities of SS, AGPP and GBSS. The accumulation courses of both amylopectin and amylose were well fitted to the logistic equation by relating amylopectin and amylose contents against days post anthesis. The simulation parameters revealed that the higher contents of amylopectin and amylose resulted from earlier initiating accumulation time and greater accumulation rate, but accumulation duration probably played a less important role for them. The amylose content in grains was mainly determined by GBSS activity as well as the activities of SS and AGPP. The change of GBSS activity reflected expression level of waxy gene was closely associated with the accumulation rate of amylose, indicating that amylose content in grains was determined by GBSS activity, especially at late grain filling stage. The difference in expression of waxy gene might be a major reason for the large difference in amylose contents between JM20 and LM21.

      Inheritance of Fructification Habit and Its Relative SSR Markers in Maize
      MENG Zhao-Dong;LI Wen-Cai;SUN Qi;ZHANG Fa-Jun;DING Zhao-Hua;WANG Li-Ming;GUO Qing-Fa;WANG Hong-Gang
      Acta Agron Sin. 2007, 33(01):  90-96. 
      Abstract ( 1944 )   PDF (1464KB) ( 1038 )   Save
      Related Articles | Metrics

      Barren tip phenomenon of the ear in maize (Zea mays L.) caused the yield loss and affected the quality of commodity grain remarkably. This phenomenon is generally regarded as a quantitative character easily affected by planting density, fertilizer and water supply, light and temperature conditions, etc. However, we found that this phenomenon varied a lot among varieties and inferred that it was caused by the difference of maize fructification habit. Based on this understanding, maize varieties were classified into two types, definite fructification type (ab. DF type) and indefinite fructification type (ab. IDF type), mainly according to the development states of the kernels on tip part of the ear. In order to probe the inheritance pattern of maize ear fructification habit, two inbred lines, lx01-3 (DF type) and wx04-1 (IDF type), and their F1, F2, BC1 and BC2 populations were analyzed on the ear fructification type under a planting density of 30000 plants per hectare in this experiment. The results showed that all ears of F1 were IDF type which means IDF type is dominant over DF type; the ratios of IDF type versus DF type ears followed a 15:1 in F2 and a 3:1 in BC1 population while all ears were IDF types except one in BC2 population, which indicates the trait of fructification habit probably controlled by two pairs of duplicate dominant genes. Two SSR markers, bnlg1601 and umc1663, were found closely linking with the genes controlling the trait of maize fructification habit. Thereby, the two genes were preliminarily located on chromosome 3 and 8 respectively.

      Analysis of the Generation Mechanism of a Ds-inserted Rice Mutant with Double Tillers at One Tillering Node
      SUN Bing-Yao;GU Fu-Gen;YUAN Yun-Xiang;TAN Jian-Zhong;WAN Zhi-Gang;LU Xiao-Ping
      Acta Agron Sin. 2007, 33(01):  97-101. 
      Abstract ( 1970 )   PDF (1110KB) ( 1084 )   Save
      Related Articles | Metrics

      Insertion mutagenesis with T-DNA or transposable elements is currently one of the most powerful tools for screening various types of mutations in higher plants, and for analyzing functional information of genes related to those mutations. By using the Ac/Ds transposable elements system in rice, a great deal of Ds-inserted mutants may be efficiently generated, and used for functional identification of genes that influence important agronomic traits, by which the researches in rice functional genomics have been greatly promoted. As a key agronomic trait related to grain production in rice and other grass species and an important property parallel to branching in dicotyledonous plants, tillering in rice has attracted more research interests. In the present study, a rice tillering mutant was isolated from a collection of Ds-inserted mutant lines, and was designated dt1 (double tillers mutant) according to its tillering phenotype of a major tiller and a minor tiller developed at the same tillering node. Both tillers were found to be productive with the ears normally emerged from each of them. The Ds-flanking sequence was cloned from this mutant by using TAIL-PCR amplification technique. The sequenced Ds-flanking sequence was used as a query to perform an online search for homologous sequence against nucleotide sequence database by NCBI-BLAST, the results indicated that the Ds-flanking sequence showed 100% identity at the nucleotide level to the sequence of clone OJ1345H02 (gi|21281466) of rice chromosome 3. The structure of the Ds-inserted gene was predicted by using software of FGENESH and GeneMark, respectively, and gotten highly similar in the number, size and location of exons within the gene. The results also showed that the Ds element was inserted into the region between transcription start site and the first exon, at 173 bp upstream of the first exon. Moreover, the product encoded by the gene was predicted by NCBI Entrez server and Pfam. It was revealed that the deduced product was a rice formin-like protein containing a highly conserved FH2-domain. Given the fact that the Ds element as big as 5.9 kb in size was inserted immediately into upstream of the first exon, it is suggested that Ds insertion probably make the gene loss it’s function, and thereby generate the rice mutant dt1. In addition, the genotyping for Ds insertion in the progeny plants of dt1 mutant indicated that these progeny plants segregated into homozygous and heterozygous types for Ds insertion and Ds free plants, which suggested that the dt1 mutant was heterozygous for Ds insertion.

      Candidate Sterility-Related Mitochondrial Genes of NCa CMS in Brassica napus L. and Its Transcription Regulated by Restorer Gene
      WEI Wen-Liang;WANG Han-Zhong;LIU Gui-Hua
      Acta Agron Sin. 2007, 33(01):  102-106. 
      Abstract ( 2029 )   PDF (769KB) ( 964 )   Save
      Related Articles | Metrics

      Previous studies verified NCa CMS was a novel CMS and would be rather important for improving cytoplasm monotony in rapeseed hybrid utilization, but the transcriptional pattern of NCa CMS was not investigated yet. So in this paper, northern blot analysis was conducted with mitochondrial RNA from floral buds of NCa CMS, maintainer line and fertile F1 using 10 mitochondrial genes as probes. Transcripts of seven probes of atp6, atp1, cox1, cox2, cob, rrn5S, rrn26S, showed no diversity among floral buds of these three materials, which indicated that the expression of these probes has no relationship with NCa sterility. However, differences in transcriptional patterns were observed when using orf222, orf139 and atp9 as probes. Three transcripts of orf222 were detected in the floral buds of NCa CMS and fertile F1 while no transcript was detected in floral buds of the maintainer line. The transcription of orf139 was similar to that of orf222 but only two transcripts of 0.8 and 0.6 kb. The atp9 probe detected a single transcript of 0.6 kb in NCa CMS and maintainer line but an additional transcript of 1.2 kb in fertile F1. The results suggested that the expression of orf222, orf139 and atp9 might be associated with NCa sterility. And how the restorer gene regulates the expression of these candidate sterility-related mitochondrial genes and then causes fertility restoration in fertile F1 is not clear and detailed research about the regulation mechanism is underway.

      Effects of Different Nitrogen Levels on Morphological and Physiological Characteristics of Relay-Planting Soybean Root
      ZHANG Han-Bin;REN Wan-Jun;YANG Wen-Yu;WU Xiao-Yan;WANG Zhu;YANG Ji-Zhi
      Acta Agron Sin. 2007, 33(01):  107-112. 
      Abstract ( 2053 )   PDF (440KB) ( 1200 )   Save
      Related Articles | Metrics

      Relay-planting soybean pattern is dominant in southern China. However, studies on relay-planting soybean are so defective that it may influence the development of soybean. Soybean accumulates vast protein by itself; and grows well with adequate nitrogen fertilizer. Most of studies have been concentrated on the effects of nitrogen on the aerial parts, but less on the roots. The present experiment was carried out to study the effects of different nitrogen levels (0, 45, 90, 135, 180, 225 N kg ha-1) on morphological and physiological characteristics in the relay-planting soybean roots by root-excavating method. The results showed that the optimal treatments on the dry root weight, root nodule number, length of first lateral root and bleeding sap were the low nitrogen levels (45 and 90 N kg ha-1) at the growth stages of V3–R5. Length of first lateral root, dry root weight and bleeding sap all were positive correlated with the application amount of nitrogen at the growth stage of R7. The relation between the root-top ratio and nitrogen levels was a quadratic curve at growth stages of V3–R5, but root-top ratio had a linear relationship with the nitrogen levels at the very late growth stage. The relation between bleeding sap-top ratio (y=Bleeding sap/dry matters) and days (x) after V3 (11th, Aug, 2005) was a negative exponential correlation (y=1.0357e-0.03823x). The content of NO3--N in bleeding sap was more than that of NH4+-N; it was also raised with the increasing of nitrogen amount. Root activity had a peak during the whole growth stage of relay-planting soybean. The activity of soybean roots was enhanced by low nitrogen levels (45 and 90 N kg ha-1). High nitrogen levels(180 and 225 N kg ha-1) postponed the appearance of the peak value of root activity at the growth stage R3 and maintained a high level(>116.00 μg g-1 FW h-1) at the very late growth stage(R7). However, whether high nitrogen levels are propitious to increasing the yield of relay-planting soybean is not clear. The relationship between characteristics of roots and the aerial parts should be studied in the future.

      Effects of Drought during Seedling Stage on Physiological Traits, Yield and Quality of Different Peanut Cultivars
      YAN Mei-Ling;LI Xiang-Dong;LIN Ying-Jie;WANG Li-Li;ZHOU Lu-Ying
      Acta Agron Sin. 2007, 33(01):  113-119. 
      Abstract ( 1931 )   PDF (497KB) ( 1114 )   Save
      Related Articles | Metrics

      Peanut is one of the ideal crops in dry farming. Drought is the main limit factor of peanut to increase yield and improve quality. Seedling stage is constantly hit by drought for summer peanut. In order to understand the suitable watering amount at peanut seedling stage, provide theoretical basis and technique for dry farming peanut producing the experiment was conducted with drought light-resistant peanut cv. Luhua 11 and drought resistant peanut cv. Nongda 818 from 2003 to 2004 in the experimental station of Shandong Agricultural University. Five treatments with watering 20 mm(serious drought stress), 40 mm(middle drought stress), 60 mm(slight-middle drought stress), 80 mm(slight drought stress) and 100 mm(CK) were made at 10 days after seedling(27 June) with three replicates in a randomized block design. The drought stress stopped at full-bloom stage(20 July) and then all treatments were irrigated 100 mm water at full-bloom stage, pod setting stage and pod filling stage separately. The results showed that the photosynthesis rate(Pn) decreased, and malondialdeyde (MDA) content increased remarkably with the drought degree raising. After rewatering, the MDA content decreased and Pn returned to the level of check rapidly, the recovery ability of Nongda 818 was bigger than that of Luhua 11. Suitable drought treatment could enhance the activities of superoxide dismutase(SOD), peroxidase (POD) and catalase (CAT), and increase the soluble protein content. The highest activities of SOD, POD, CAT and soluble protein content presented at the slight-middle drought treatment(watering 60–80 mm ) for Luhua 11, but at the middle drought treatment(watering 40–60 mm ) for Nongda 818. At the same drought treatment, especially at serious drought treatment(watering 20 mm), the activities of SOD, POD, CAT of Nongda 818 were obviously higher than that of Luhua 11. After rewatering, the activities of SOD, POD, CAT and soluble protein content reduced significantly, but the activities of SOD, POD, CAT of Nongda 818 were still higher than that of Luhua 11. With the drought degree raising, pod and kernel yields substantially decreased and the yield losses of Nongda 818 were less than that of Luhua 11. The irrigating amount at peanut seedling stage is no less than 60–80 mm to avoid the yield loss. Middle and slight drought stress at seedling stage could increase the protein content of peanut kernel, and have a little effect on fat content. Serious drought stress at seedling stage remarkably decreased oleic content and the ratio of oleic/linoleic(O/L), increased linoleic content of peanut kernel, and have a little effect on protein content. The optimal irrigating amount at seedling stage for the best kernel quality of Luhua 11 is 60–80 mm and that of Nongda 818 is 40–60 mm.

      Improvement of Callus Induction Efficiency in Anther Culture of Autotetraploid Rice
      CHEN Hong;QIN Rui-Zhen
      Acta Agron Sin. 2007, 33(01):  120-125. 
      Abstract ( 2025 )   PDF (456KB) ( 1010 )   Save
      Related Articles | Metrics

      Improving anther culture inductivity is important for improvements of plant differentiation rate and plant production rate in rice. Four pedigree seed varieties of autotetraploid rice, Linglun, 02428, Pei’ai 64 and Lunhui 422 and the corresponding diploid plants were used in the present work of anther culture. 26 kinds of induction medium were designed on the factors including agar concentration (0.5%, 0.75% and 1%), variety (sucrose and maltose) and concentration (60 and 80 g L-1) of carbon source, different varieties of basic media (MS, N6, M8, NB) and hormone (KT and Zip) to determine appropriate combination on callus induction. The results indicated that the inductivity of 60 g L-1 (18.7%) is notably better than that of 80 g/L (8.7%) when using sucrose as carbon source. Meanwhile, using 0.75% of agar obtained the highest inductivity which is 20.8% among twelve media combination, and the average induction rate of autotetraploid japonica (16.4%) is higher than that of autotetraploid indica (7.3%). The N6 and NB media were better than MS and M8 for improving callus inductivity in tetraploid rice, especially in Japonica rice, whether sucrose or maltose was used as carbon source. The media with supplement of KT and Zip could induce more calli conspicuously, and the highest inductivity was 84%. It was also observed that the calli induced by the addition of KT were of high quality to produce seedlings. Among total 26 kinds of media, 6 types led to higher inductivity in japonica rice whereas 2 types in indica rice. Furthermore, there were 3 types media produced not only higher callus inductivity but also higher plant production rate than others. In conclusion, the induction efficiency of anther callus for one certain genotype is remarkably different with various media, which implies that the genotype is of selection for the induction media.

      Coupling Effects of Irrigation and Nitrogen Fertilizer on Protein Composition and Quality of Winter Wheat Cultivar Jimai 20
      WANG Xiao-Ying;HE Ming-Rong
      Acta Agron Sin. 2007, 33(01):  126-131. 
      Abstract ( 1921 )   PDF (493KB) ( 1150 )   Save
      Related Articles | Metrics

      Many studies have indicated that irrigation and nitrogen fertilizer are the major factors influencing wheat quality. Protein content, protein composition and size distribution of glutenin in wheat grain are significantly modified by the rate and timing of nitrogen fertilizer. It is also found that irrigation has diluting effect on grain quality and this effect is lessened by more nitrogen application. Although the respective effect of irrigation and nitrogen fertilizer on wheat quality has been extensively studied, especially in arid area and under low yield condition, it is little known about the coupling effects of irrigation and nitrogen on wheat quality under high yield condition. In this experiment, with a new method of protein fraction extraction, the effect of different irrigation and nitrogen application regimes on grain yield, protein content, protein composition and grain quality of Jimai 20 (a winter wheat cultivar with strong gluten) was investigated on high fertility soil in order to find the optimal regime of irrigation and nitrogen with high grain yield and excellent quality. The result indicated that irrigation was a crucial factor influencing grain quality. The contents of grain protein and monomeric protein in irrigation treatments were significantly lower than these in non-irrigation treatment, but there were no significant differences among irrigation treatments. Soluble glutenin (low molecular weight glutenin) content was increased while insoluble glutenin (high molecular weight glutenin) content and polymerization index (insoluble glutenin/total glutenin) were reduced as irrigation frequency added. In addition, both dough development time and stability time had the same tendency as insoluble glutenin and polymerization index, which suggested retarded formation and accumulation of insoluble glutenin was the major reason of worsen grain quality with added irrigation frequency. Compared with N split application (50% of total N fertilizer was applied at preplanting and the remainder at jointing), N fertilizer totally top-dressed at jointing led to significantly improved grain quality and similar grain yield. Therefore, it is proposed that N fertilizer can be totally top-dressed at jointing under high yield condition for the sake of high grain yield and excellent quality.

      Effects of Arsenic on Nitrogen Metabolism of Flue-cured Tobacco (Nicotiana tabacum L.)
      CHANG Si-Min;MA Xin-Ming
      Acta Agron Sin. 2007, 33(01):  132-136. 
      Abstract ( 1843 )   PDF (351KB) ( 1018 )   Save
      Related Articles | Metrics

      Arsenic, a high toxic heavy metal, is one of the most serious contaminants in soil and a potential threat to crop growth and human health. Nitrogen metabolism plays an important role in growth and development as well as in yield and quality of flue-cured tobacco. It is necessary to study arsenic toxicity to nitrogen metabolism of flue-cured tobacco. Therefore, a systematic experiment was conducted on the farm of Henan Agricultural University, Zhengzhou, China. using Yunyan 85 (Nicotiana tabacum L.) planted in 400 mm×340 mm plastic pots, with the treatments of five arsenic levels of 0(CK), 5, 20, 40, and 60 mg·kg-1 [added to sodium arsenate (Na3AsO4·12H2O)] to determine the effects of arsenic toxicity on metabolism of nitrogen. The results showed that arsenic toxicity significantly affected nitrogen metabolism in flue-cured tobacco. On one hand, activity of nitrate-reductase (NR) during the growing period was reduced, and on the other hand, glutamine synthetase activity (GS) during the growing period was increased. These indicated that assimilation of NO3--N was inhibited and assimilation of NH4+-N was enhanced by arsenic toxicity. The activities of both glutamate-pyruvate transaminase (GPT) and asparaginase (ASG) during the growing period, and content of the free amino acids after budding stage were increased, indicating that arsenic toxicity enhanced nitrogen transformation metabolism in flue-cured tobacco. In the mean time, compared with those in CK, protein content during the early growing stage and nicotine content during the whole growing period were decreased. However, protein content was increased during the middle and late growing stages.

      Characteristics of Dry Matter Accumulation and Distribution in Conventional indica Rice Cultivars with Different Nitrogen Use Efficiency for Grain Output
      DONG Gui-Chun;WANG Yu-Long;ZHANG Chuan-Sheng;ZHANG Yue-Fang;CHEN Pei-Feng;YANG Lian-Xin;HUANG Jian-Ye;LONG Yin-Cheng
      Acta Agron Sin. 2007, 33(01):  137-142. 
      Abstract ( 1986 )   PDF (464KB) ( 1136 )   Save
      Related Articles | Metrics

      Improving nitrogen use efficiency in crops is of great importance both in crop production and environmental protection. Genetically improving crop varieties so as to make full use of the potentials in nitrogen uptake and utilization has been considered as one of the most economical and effective ways to enhance nitrogen use efficiency in crops. Nitrogen use efficiency depends on the ability of nitrogen uptake and utilization in rice plant. Many studies have shown that there exist genotypic differences in nitrogen use efficiency for biomass and grain production in rice. Yet, little information in the characteristics of yield components, biomass production and allocation, nitrogen uptake and allocation and structure of root system in rice varieties with higher nitrogen use efficiency has been reported. In this study, 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight (including root system, stem and sheath, leaves, ear), nitrogen content of different organs was measured. The tested rice cultivars were classified into 6 types (i.e. A, B, C, D, E and F, A was lowest, F was highest) based on their nitrogen use efficiency for grain output (NUEg) level by the MinSSw method, to study their characteristics of dry matter accumulation and distribution. Results ware as follows: (1) Difference of NUEg of the cultivars used in this study was very large, the averages of NUEg for A, B, C, D, E and F were 20.51, 31.04, 35.64, 39.46, 43.55 and 50.92 g grain·g-1N in 2001, and 24.33, 31.61, 35.83, 39.06, 43.51, 50.00 g grain·g-1N in 2002, respectively; (2) Difference of biomass among cultivars of different types was not significant, while dry matter accumulation of the cultivars with high NUEg level was small at heading stage, its dry matter production after heading was large and the ratio of that to biomass was high; (3) Difference between cultivars of different types in the ratio of dry root weight to dry matter weight per plant (DMWP)and the ratio of dry stem and sheath weight to DMWP was not significant at heading stage, while those at mature stage in the cultivars with high NUEg level was lower; (4) The smaller the ratio of dry leaf weight to DMWP, the longer the ratio of dry panicle weight to DMWP in the cultivars with high NUEg level at heading stage and maturing stageble.

      Response of Flag Leaf Lipid Peroxidation and Protective Enzyme Activity of Wheat Cultivars with Different Heat Tolerance to High Temperature Stress after Anthesis
      JIANG Chun-Ming;YIN Yan-Ping; LIU Xia;WANG Zhen-Lin
      Acta Agron Sin. 2007, 33(01):  143-148. 
      Abstract ( 2227 )   PDF (428KB) ( 1137 )   Save
      Related Articles | Metrics

      In order to elucidate the antioxidation mechanism of wheat subjected to post-anthesis high temperature stress, changes of MDA content and protective enzyme activity under high temperature stress at different grain filling stages were studied by using two different heat-tolerance winter wheat (Triticum aestivum L.) cultivars SN1391 and GC8901. High temperature stresses were made from the 8th to 10th day after anthesis (T1) and from the 15th to 17th day after anthesis (T2) respectively by plastic sheds. Antioxidant system in flag leaf could be more efficiently operated in T1 to reduce lipid peroxidation, while the injury of T2 couldn’t be recovered. In T1, the activity of SOD and CAT significantly increased, the increasing time of CAT was later than that of SOD, the two enzymes cooperated with each other so that they could retard the senescence of flag leaf. On the 28th day after anthesis, the MDA content of SN1391 was lower than that of GC8901 in corresponding treatment. The SOD activity increasing extent of SN1391 was much bigger than that of GC8901, and the recovery capability of CAT activity was greater in SN1391 than in GC8901. In T2, the activity of SOD decreased. Although the activity of CAT was higher than that of CK, it couldn’t abate the degree of flag leaf lipid peroxidation efficiently. This indicated that SOD played an essential role in protective enzyme system. The ability of POD eliminating H2O2 was diminished in T1 and the activity of POD significantly increased in T2, which probably damaged the leaves and accelerated their senescence. According to the results above we concluded that with the post-anthesis development, the wheat heat tolerance is deteriorated, so field management should be enhanced especially in middle and late grain filling stages in order to ease the injury of high temperature stress.

      RESEARCH NOTES
      The Stigma Observation on Foxtail Millet (Setaria italica Beauv.) Male-sterile Line “81-16” with High Outcross Seed Setting
      CUI Gui-Mei;NIU Tian-Tang;ZHANG Fu-Yao;YUAN Ai-Ping;SUN Yi
      Acta Agron Sin. 2007, 33(01):  149-153. 
      Abstract ( 2048 )   PDF (873KB) ( 926 )   Save
      Related Articles | Metrics

      Foxtail millet (Setaria italica Beauv.) is one of the important cereal crops in the arid and semi-arid regions of Northern China, but there is no official report on millet hybrid being used on a large-scale up to the present. One of the main reasons is the very low outcross seed setting percentage of millet male-sterile lines.
      In the present research the exsertion score of the stigmas was significantly positively correlated with the outcross seed setting percentage for millet male-sterile lines (r0.001=0.9597**). Economic Crop Research Institute, Shanxi Academy of Agricultural Sciences successfully selected a new photoperiod-sensitive male-sterile millet line “81-16”, with elite stigma characters. Its sterile degree is 100% and outcross seed setting percentage achieves 61%. “Gao 84A” and “Guang 683A/81-16” derived from “81-16” also exhibited desirable stigma characters. We studied the pistil characters of “81-16” with phytomorphology method. Another photoperiod-sensitive male-sterile millet line with regular stigma, “1500”, was used as a check in the study. The results showed that exsertion degree of stigma out of glume and exsertion rate of “81-16” were significantly greater. Stigma characters of “81-16” were more stable than those of “1500” (measured by standard deviation). The pistil of “81-16” was robust with large areas of stigma and lots of pinniform branches. The intervals between branches in “81-16” were same as in “1500”. Pistil lengths of “1500” were similar to those of “81-16”, but area of stigma was only 56% of that of “81-16”. Style of “1500” was longer, but thinner than those of “81-16” and its ovary was smaller. The infirmness of pistils led them difficult to stretch out of glumes at blooming.
      By studying pistil characters of male-sterile lines in foxtail millet with phytomorphology method, we could forecast their outcross seed setting percentage. Morphological parameters of pistil reflected the vitality of stigma directly and areas of stigma were positively correlated with outcross seed setting percentages. Some suggestions about increasing the outcross seed setting percentage were raised in this paper that the selection of stigma characteristics for millet male-sterile lines should be emphasized.

      Molecular Identification of a Novel Phytophthora Resistance Gene in Soybean
      ZHU Zhen-Dong;HUO Yun-Long;WANG Xiao-Ming;HUANG Jun-Bin;WU Xiao-Fei
      Acta Agron Sin. 2007, 33(01):  154-157. 
      Abstract ( 1988 )   PDF (267KB) ( 902 )   Save
      Related Articles | Metrics

      Phytophthora root rot, caused by Phytophthora sojae Kaufmann & Gerdemann, is one of the most important diseases in soybean throughout the world. Deployment of resistant cultivars is the preferred method for controlling this disease. In this study, a dominant Phytophthora resistance gene was identified and mapped by using microsatellite markers. The gene, designated RpsYB30, was identified in soybean cultivar Youbian 30, located on soybean MLG L, and flanked by microsatellite markers Satt497 and Satt313 with genetic distances 4.4 cM and 3.3 cM, respectively. RspYB30 is a novel Phytophthora resistance gene to be first found on MLG L genes.

      Isolation and Characterization of Microsatellites from Ramie [Boehmeria nivea (L.) Gaud.]
      JIANG Yan-Bo;JIE Yu-Cheng;ZHOU Jian-Lin;XING HuCheng;SHE Wei
      Acta Agron Sin. 2007, 33(01):  158-162. 
      Abstract ( 1988 )   PDF (1093KB) ( 1067 )   Save
      Related Articles | Metrics

      Ramie [Boehmeria nivea (L.) Gaud.] is an important bast fiber crop. To study genetic background of this species, the microsatellite markers of ramie were isolated and characterized. Microsatellites were captured by using ramie cultivar Luzhuqing digested with MseⅠand ligated with adaptors and then linked to biotinylated oligoprobe (CT)15 attached to streptavidin-coated magnetic beads (Dynabeads M-280). Double-stranded targeted fragments were obtained by PCR amplification using 21-mer adaptor oligonucleotide as primer, 300–1 000 bp DNA fragments were recovered from 1.5% agarose gel electrophoresis and then religated into pMD18-T vector and transformed into competent DH5α cell. Thus a genomic library containing inserts (GA)n repeats fragments was constructed and then screened by PCR using anchored simple sequence repeats as primers for the presence of (GA/CT)n repeats. A total of 22 clones were identified as positives after randomly picked 36 clones, all the 22 clones contained microsatellites and enrichment efficiency was 61.1%, among the existed microsatellites, the expected type of GA/CT is the most popular which accounted for 83.3% and is compatible to the (CT)15 probe, however some other types including (TG/AC)n and more complicated simple sequence repeats with 3 and 6 bases, such as (GAC)n, (ACG)n, (TCT)n, (TCG)n, (GAA)n, (CCGACG)n, (GAGAAA)n could also be detected in the microsatellite-enriched library. About 18 microsatellite loci were found after sequencing. Finally, 18 primer pairs were designed on the basis of DNA sequences flanking the repeat motif. The length of GA/CT repeat units varied between 7 and 40 with a mean value of 19.2, which suggests that they would be polymorphic and powerful genetic markers in ramie. These SSR markers are useful for ramie genotype identification, gene and QTL analysis, marker-assisted selection in breeding and pedigree analysis.

      SSR Markers and Preliminary Chromosomal Location of a Powdery Mildew Resistance Gene in Common Wheat Germplasm N9134
      WANG Chang-You;JI Wan-Quan;ZHANG Gai-Sheng;WANG Qiu-Ying;CAI Dong-Ming;XUE Xiu-Zhuang
      Acta Agron Sin. 2007, 33(01):  163-166. 
      Abstract ( 2073 )   PDF (680KB) ( 1040 )   Save
      Related Articles | Metrics

      A powdery mildew resistance gene, originating from wild emmer (Triticum dicoccoides Thell.) accession ‘AS846’, was transferred to a common wheat line N9134. N9134 was highly resistant to the prevailing Erysiphe graminis f. sp. tritici Race Guanzhong No.4 in Shaanxi Province. F1 plants of the crosses susceptible cultivars (Shaan 160 and Shaanyou 225)×N9134 were highly resistant to the powdery mildew race and the ratio of resistant and susceptible plants in F2 progeny fitted the expected 3 to 1. The results indicated that powdery mildew resistance of N9134 at seedling stage was controlled by a single dominant gene. The gene is temporarily designated PmAS846. 92 and 84 F2 plants of the crosses Shaan 160×N9134 and Shaanyou 225×N9134 were used for SSR analysis, respectively. 3 of 66 wheat microsatellite primer pairs WMS67, WMS213 and WMS37 generated polymorphic DNA fragments between the resistant and susceptible plants DNA pools. By analyzing the polymorphic markers in these segregating populations, the microsatellite locus Xgwm67 located on chromosome 5BL was found to be linked to the resistance gene PmAS846 with the estimated genetic distance of 20.6 cM, suggesting this gene might be located on the long arm of chromosome 5B.

      Effect of Disulfide Bond-Containing Protein on Texture of Cooked Rice
      CHEN Neng;XIE Li-Hong;DUAN Bin-Wu
      Acta Agron Sin. 2007, 33(01):  167-170. 
      Abstract ( 1976 )   PDF (322KB) ( 959 )   Save
      Related Articles | Metrics

      11 rice cultivars with different amylose contents were chosen to determine the impact of protein on forming a viscosity curve when treated with reduced reagent dithiothreitol (DTT) to disrupt the protein disulphide bonds, and then to understand how protein affect the eating quality of cooked rice. DTT decreased RVA pasting temperatures and peak viscosities of flours with different degrees in all cultivars, while increased breakdown viscosities in 5 cultivars. DTT also changed the slopes of the linear parts of the curves for each variety. The addition of DTT to the cooking water decreased the hardness, while increased the adhesiveness of cooked rice. The disulfide bond-containing protein had a substantial impact on the pasting and cooking properties of rice. RVA measurements indicated that in addition to the disulphide bond network, protein hydration based increase of the gelatinized paste concentration contributed to the enhancements of the paste rigidity during cooking. The role of disulphide bonds in augmenting the breakdown viscosity values indicated that in the absence of the rigidity conferred by the disulfide-bound protein, swollen starch granules broke apart more easily when shear stress was high. From these observations, it was anticipated that disulfide bond-containing protein agency also played a role in the texture of cooked rice; this was confirmed by cooking rice in the presence of DTT. The agency of protein network increased hardness and decreased the stickiness of the cooked rice. Furthermore, the observation that the effects of DTT on high-amylose rice texture properties were slight suggested that, apart from an agency of protein network, a strengthening of an amylose barrier present in the rice endosperm seemed equally or more important.

      Preliminary Hyperspectral Estimation Models for Crude Fat Content in Corn
      YI Qiu-Xiang;HUANG Jing-Feng;WANG Xiu-Zhen;QIAN Yi
      Acta Agron Sin. 2007, 33(01):  171-174. 
      Abstract ( 2115 )   PDF (253KB) ( 962 )   Save
      Related Articles | Metrics

      The hyperspectral reflectances of leaf, stem, ear and sheath and corresponding crude fat content in six kinds of corn (Zea mays L.) were determined. Correlation between crude fat content and spectral measurements was calculated. The crude fat content of dried ground leaves was best predicted with the first derivative reflectance. Precision evaluation indicated that the exponential model derived from the first derivative reflectance at 1954 nm was the best for the estimation of corn crude fat content.

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:
Yan Chun-ling
CN 11-1809/S
ISSN 0496-3490
Post subscription code: 82-336

WeChat
  • 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
Tel: 8610-82108548

WeChat