陆地棉抗旱性与SSR分子标记的关联分析

Association Analysis of Drought Tolerance and SSR Markers in Upland Cotton

【目的】了解陆地棉抗旱性和寻找与陆地棉抗旱性相关的分子标记,挖掘与抗旱性状相关的优异等位变异。【方法】以191份陆地棉栽培种组成的自然群体为材料,在萌发期采用质量分数为15%的PEG6000竖直滤纸法对191份材料进行胁迫处理,测定其发芽率。根据隶属函数值对萌发期抗旱性划分抗旱级别。利用关联分析的方法以74对SSR引物对该自然群体进行基因组变异扫描。在利用Structure 2.3.4分析该自然群体的遗传结构的基础上,使用Tassel 2.0的GLM模型将基因型数据与萌发期抗旱性状进行关联分析,寻找与抗旱性状相关的分子标记。【结果】筛选出强抗旱材料46份,中等抗旱材料59份,干旱敏感材料86份;群体结构分析将191份材料划分为2个亚群,分别包含123份和68份材料;通过关联分析获得与陆地棉萌发期抗旱性显著相关的分子标记15个,各位点对表型变异解释率为2.2%~7.49%。【结论】本研究筛选出强抗旱材料46份,获得与萌发期抗旱性相关的分子标记15个,可供棉花抗旱标记辅助选择育种利用。

[Objective] The aims of this study are to detect drought tolerance of upland cotton （Gossypium hirsutum L.）, to find the molecular markers associated with the drought tolerance traits, and to excavate elite allelic variation associated with drought re- sistance traits. [Method] We selected 191 cultivars （lines） as experimental materials. The germination rates during sprouting peri- od were evaluated in 15% （mass fraction） PEG6000 stress. Drought tolerance was classified according to the membership func- tion values to drought resistance at sprouting period. A total of 74 pairs of simple sequence repeat （SSR） primers were employed to detect the genomic variation of the natural population. Based on the analysis of the genetic structure of the natural population using Structure 2.3.4, the GLM model of Tassel 2.0 was used to correlate the genotype data with the drought tolerance traits at germination stage to find the molecular markers associated with the drought tolerance traits. [Result] A total of 46 high-resis- tance materials, 59 medium-drought resistant materials and 86 drought-sensitive materials were identified; population structure analysis divided the 191 materials into two subgroups, consisting of 123 and 68 materials, respectively; the association analysis showed that 15 SSR sites related to drought resistance at germination stage （P 〈 0.05）, explained phenotypic variation ranged from 2.2% to 7.49%. [Conclusion] We screened out 46 drought-resistant materials and 15 molecular markers related to drought tolerance, which may be used for cotton drought-resistant marker-assisted breeding.