【作者】 张红霞；

【导师】 马翎健；

【作者基本信息】 西北农林科技大学 ， 作物遗传育种， 2016， 硕士

【摘要】 人工合成小麦的创制为利用小麦近缘种属中的优异资源,拓展并丰富小麦遗传基因库,进一步鉴定、挖掘和运用优异基因创造了条件。本试验以国际玉米小麦改良中心引进的86份人工合成小麦品系和我国24份常规小麦品种构建自然群体,在杨凌调查了2年的穗长、穗粒数和千粒重表型性状,结合分布于小麦21条染色体上的201个SSR标记进行了遗传多样性分析、群体结构分析、聚类分析和连锁不平衡分析。在考虑群体结构(Q)的基础上进行分子标记和表型性状的关联分析。主要结果如下：1.2014年和2015年在陕西杨凌调查了110份材料的3个农艺性状。统计分析表明,人工合成小麦的穗粒数为变异系数最大的性状。人工合成小麦品种的三个性状差异均达到极显著水平(P<0.01)。说明供试小麦品种间各性状间具有丰富的多样性。2.选用201对多态性SSR标记对86份供试人工合成小麦品种进行基因型分析,共检测到了1323个等位变异,平均值为6.57；遗传多样性指数平均值为0.755,多态性信息含量(PIC)平均值为0.719。等位变异总数和平均等位变异丰富度D>B>A,遗传多样性指数和多态性信息含量B>D>A。说明由国际玉米小麦改良中心提供的人工合成小麦D基因组具有较高的遗传多样性。3.群体结构分析将供试材料群体分为3个亚群。UPGMA聚类分析将供试材料分成3个大类,两种分析结果基本一致。这表明大部分供试人工合成小麦的遗传背景与常规种质材料存在较大差异,部分材料可能产生基因交流或受环境因素影响。4.201对SSR标记中,共检测到20101对连锁位点,其中有共线性位点(P<0.05)601对。连锁不平衡衰减距离的“基准线”是r2=0.9303,人工合成小麦全基因组LD衰减距离为9.85cM。衰减距离较大,发生的重组较低,可为后续的关联分析定位提供参考。5.两年均能检测到的显著关联标记有21个。这些显著性标记为进一步的小麦分子标记辅助育种提供资源。本研究对利用小麦近缘种属中的优良资源,拓展和丰富小麦遗传基因库,进一步发掘和利用优良基因具有重要意义。更多还原

【Abstract】 The creation of Synthetic hexaploid wheat provides conditions for the utilization of wheat-related species on the excellent resources, genetic diversity and elite genes. Association mapping (AM) is a new way to identify the association between the target traits and genetic markers based on linkage disequilibrium (LD) that is a supplementary of QTL. In this study, 110 wheat accessions consisted of 86 SHW germplasms and 24 conventional wheat varieties were evaluated for 3 yield-related traits in two years at Yangling. Genetic diversity, population structure, UPGMA and linkage disequilibrium analysis wan conducted based on 201 SSR markers across the 21 chromosomes in wheat. Association mapping between molecular markers and phenotypic traits was analyzed with the consideration of population structure (Q). The major results were as follows:1. Three agronomic traits, thousand kernels weight (TKW), grains per spike (GPS) and spike length (SL) were estimated in 2014 and 2015 at Yangling. Statistical analysis showed that the highest coefficient of variation was the GPS in the synthetic hexaploid wheat. The difference of three traits of the SHW showed a very significant level. It indicated that synthetic hexaploid wheat with abundant phenotypic diversity for association mapping.2. Genotype analysis was performed on 110 Wheat Cultivars with 201 polymorphic SSR markers.1323 alleles were detected with an average of 6.57 per locus. The genetic diversity with a mean value of 0.755. Polymorphic information content (PIC) of each primer with the average level of 0.719. Number of alleles and average genetic richness showed on genome D>B>A, genetic diversity and PIC displayed on genome B>D>A. Genetic diversity and PIC positively correlated with allele number. It revealed that the D genome provided by the CIMMYT has high genetic diversity and rich genetic variation.3.110 accessions were assigned to three subgroups (SG) based on delta K (AK). The clusters by UPGMA based on Nei’s1973 mostly agreed with STRUCTURE analysis results. It indicated that genetic background of most synthetic hexaploid wheat germplasms varied greatly comparing with conventional varieties while some materials may produce gene exchange or influenced by environmental factors.4. A total of 20101 locus pairs were calculated based on 210 SSR markers and among them, 610 linked locus pairs were detected (P<0.01). The critical value of r2 was 0.9303 based on the distribution of 95% unlinked r2. LD decay curve showed the LD extends about 9.85 cM in whole genome of synthetic hexaploid wheat. The linkage disequilibrium analysis in this experiment can be a reference for the next association analysis.5.21 significant markers (P<0.05) were detected both in 2014 and 2015. The molecular markers associated with phenotypic would provide reference for the selection of hybrid combination, discovery of alleles and the molecular marker assisted breeding.更多还原