小麦RIL群体中籽粒蛋白质组分的分离与主要品质性状的相关分析

利用普通小麦重组自交系群体为材料,研究了小麦籽粒蛋白质组分在后代群体中的分离和分布,同时对籽粒蛋白质组分与其它主要品质指标的关系进行了研究.结果发现籽粒蛋白质组分在群体后代中表现为微效多基因控制的数量性状,相对亲本的性状变异较大.醇溶蛋白和谷蛋白相对含量与湿面筋含量、SDS沉降值之间呈显著正相关,与硬度呈正相关.清蛋白、球蛋白相对含量与湿面筋含量、SDS沉降值和硬度呈负相关.     

利用重组自交系群体进行抗玉米矮花叶病研究

玉米矮花叶病在世界范围内广泛分布，且危害十分严重．因此正确认识玉米（Zea mays L．）对矮花叶病的抗性机制非常必要．基于此，本研究利用遗传差异较大的Mo17（高感玉米矮花叶病）和黄早四（高抗玉米矮花叶病）为亲本采用一粒传法构建了F9代重组自交系（Recombinant inbred line，RIL）分离群体，共256系．通过人工接甘蔗花叶病毒MDB株系（Sugarcane mosaic virus strain MDB, SCMV-MDB）对该分离群体进行了抗病性分析，统计了发病率和病情指数两项指标，根据这两项指标的频数分布图可知：玉米对矮花叶病的抗性主要由主基因控制，但不能排除还有微效基因的可能性．     

皖草2号RIL群体5个农艺性状的QTL定位

皖草2号是我国育成的第1个高粱和苏丹草的杂交品种,具有产量高、品质优、适应性强的特点。以皖草2号重组自交系（RIL）群体为材料,对其株高（PH）、茎粗（SD）、分蘖数（TN）、单株鲜质量（FW）和单株干质量（DW） 5个农艺性状进行了遗传分析;利用SSR分子标记,构建了皖草2号RIL群体的遗传图谱,并对株高、茎粗、分蘖数、单株鲜质量和干质量5个农艺性状进行QTL定位。结果表明：（1）RIL群体的平均株高、茎粗、分蘖数、单株鲜质量和单株干质量都位于2个亲本之间;除分蘖数外,其他4个性状呈正态分布。（2）利用147个SSR标记构建了10个连锁群的遗传图谱,总遗传距离为1 030.4 cM,标记间的平均距离为7.14 cM;进一步利用遗传图谱定位了控制5个农艺性状的QTL位点共22个,其中PH位点1个、SD位点2个、TN位点6个、FW位点7个、DW位点6个,在这22个QTL位点中,qFW-6位点贡献率最小,为3.61%;qDW-8位点贡献率最大,为34.24%。研究结果可为饲用高粱与苏丹草杂交种的分子标记辅助育种提供一定的理论参考。     

Molecular mapping of QTLs for root response to phosphorus deficiency at seedling stage in wheat (Triticum aestivum L.)

Phosphorus (P) deficiency in the soil is one of the major abiotic stresses that limit plant growth and crop productivity throughout the world. Development of cultivars with improved P-deficiency tolerance is an efficient strategy for sustainable agriculture. Plant roots play an important role in crop growth and development, especially in nutrient uptake and improvement of P-efficiency. Mapping quantitative trait loci (QTLs) for root traits and their response to low P stress at seedling stage will facilitate the development of P-efficient wheat cultivars. In this study, 30 QTLs (LOD>2.0) were mapped for the three root traits, such as root length, root number and root dry matter under different P supply conditions and their response to P-stress. These QTLs were distributed on 14 chromosomes, with each of the 5 QTLs explaining more than 10% phenotype variance. Analyses showed that root traits and their response to P-deficiency were controlled by different QTLs. In addition, alleles with positive effects were separated on both parents, and wheat cultivars with improved P-efficiency could be developed by accumulating these positive effect alleles together.     

Molecular mapping of QTLs for root response to phosphorus deficiency at seedling stage in wheat (Triticum aestivum L.)

Phosphorus (P) deficiency in the soil is one of the major abiotic stresses that limit plant growth and crop productivity throughout the world. Development of cultivars with improved P-deficiency tolerance is an efficient strategy for sustainable agriculture. Plant roots play an important role in crop growth and development, especially in nutrient uptake and improvement of P-efficiency. Mapping quantitative trait loci (QTLs) for root traits and their response to low P stress at seedling stage will facilitate the development of P-efficient wheat cultivars. In this study, 30 QTLs (LOD>2.0) were mapped for the three root traits, such as root length, root number and root dry matter under different P supply conditions and their response to P-stress. These QTLs were distributed on 14 chromosomes, with each of the 5 QTLs explaining more than 10% phenotype variance. Analyses showed that root traits and their response to P-deficiency were controlled by different QTLs. In addition, alleles with positive effects were separated on both parents, and wheat cultivars with improved P-efficiency could be developed by accumulating these positive effect alleles together.     

利用小麦重组自交系群体分析SIG与品质性状的相关关系

对谷蛋白溶涨指数(swelling index of glutenin,SIG)的测定方法进行了改进,确定了试验的最佳面粉用量为0.24g,并利用小麦京771×Pm97034产生的重组自交系(RIL)群体,对SIG与几个品质性状在RIL群体中的分离和分布规律及其相关性进行了研究。结果表明,这些品质性状在重组自交系群体中呈连续变异,分布频率大致接近正态分布,同时存在双向超亲分离现象。除膨胀势外,SIG与其他5个品质性状之间都具有极显著的相关性,其中与Zeleny沉淀值的相关系数最大(r=0.783),其次是面筋指数、湿面筋含量、GMP含量和碱性水保持力,多元逐步回归分析表明Zeleny沉淀值、面筋指数和碱性水保持力可以解释SIG的69.8%的表型变异。     

GMP在RIL群体中的分离及与SIG、AWRC和WPC的相关分析

谷蛋白大聚合体(GMP)是谷蛋白聚合体的重要组成部分,其含量反映了谷蛋白聚合体粒度分布状况。本文以一个普通小麦的重组自交系后代群体为试验材料,对GMP的提取、分离和测定方法以及GMP含量、碱性水保持力(AWRC)、膨胀系数(SIG)及湿面筋含量的群体变异、GMP含量与其它三项品质指标的相关性进行了研究。结果表明：该GMP含量的提取、分离和测定的方法具有简单、快速、稳定、经济的特点,实验结果相对准确,可信度高,重复性好。GMP含量、AWRC、SIG及湿面筋含量在群体后代中表现为微效多基因控制的数量性状,相对亲本的性状,变异较大。GMP含量与SIG、湿面筋含量呈极显著相关(r=0．63,r=0．56),而与AWRC没有明显的线性相关。     

Development, chromosome location and genetic mapping of EST-SSR markers in wheat

A number of 151695 wheat expression sequence tags （ESTs） that originated from GenBank/dbEST from July 14, 2003 to August 24, 2004 were used to search for simple sequence repeats （SSRs） with motif 2-5 bp, and 2038 simple sequence repeats （EST-SSRs）, which accounted for 1.34% of EST database, were identified. Based on these SSR sequences, 249 EST-SSR primer pairs and 166 amplified clear bands in various wheat cultivars were designed. These EST-SSR markers can be used as new molecular markers in wheat and related species. Using Chinese Spring nulli-tetrasomic lines, 93 EST-SSR primer pairs and 193 EST-SSR loci were located on 19 wheat chromosomes except for 4A and 4B. Forty-three loci were mapped on 11 chromosomes of the genetic framework map previously constructed using recombinant inbred lines.     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.