棉花适宜机采相关性状的SSR标记关联分析及优异等位基因挖掘

棉花机械采收对品种的生育期、株型及对脱叶剂敏感度有较高的要求。本研究利用覆盖全基因组有多态性的214对SSR标记对118份含有一个或多个机采性状的种质资源的株高、始节高、始节位、第一果枝平均长度、生育期及脱叶率6个机采相关性状进行关联分析。利用Structure 2.3.1软件进行群体结构分析,并结合2年2点12个重复的田间表型数据,采用Tassel 5.0软件的混合线性模型MLM关联定位。结果检测到460个等位基因,涉及905个基因型,基因多样性指数平均为0.5151,PIC值平均为0.4587,基因多样性指数和PIC值都大于平均数的标记有99个,占总标记数的46.3%,说明该批SSR标记具有较多的等位变异数和较高的遗传多样性。群体结构分析将118份供试材料划分为4个亚群,结果显示各类群中材料与地理来源无对应关系。关联分析结果显示4种环境中,在显著条件下(P0.05),共检测到124个与6个机采相关性状相关的位点,对表型变异解释率范围为2.23%~14.15%;其中在极显著条件下(P0.01),共检测到20个与机采相关性状相关的位点,对表型变异解释率范围为4.84%~14.15%。基于本研究的结果,鉴定出典型的载体材料11份,分别为系7、金垦9号、Y11、豫棉18、AY-4、K2、朝阳棉2号、DZ22、中棉所43、C2和关农长早B14。以上发掘出的控制棉花适宜机采性状的优异等位基因及优异亲本资源,可为机采棉的分子辅助选择育种提供理论依据。

Association Analysis and Exploration of Elite Alleles of Mechanical Harvest-Related Traits with SSR Markers in Upland Cotton Cultivars (Gossypium hirsutum L.)

Cotton suitable for mechanical harvest should have higher requirement in traits, for example, shorter growth period, ideal plant type and high sensitivity to defoliant. A total of 214 pairs of SSR with high polymorphism and uniform distribution on whole genome were used to scan polymorphism in 118 cotton varieties with one or more mechanical harvest-related traits. Molecular marker data and six phenotypic traits were analyzed by the method of MLM (mixed linear model) in Tassel 5.0 on the basis of population structure, analysis loci with elite allelic variation and typical materials carrying elite alleles were identified based on phenotypic effect values. We detected 460 alleles and 905 genotypes. The average genetic diversity index was 0.5151, and the average polymorphic information content (PIC) per marker was 0.4587. Ninety-nine markers achieved the aforementioned average values accounted for 46.3% of the total markers, shows that the SSR markers have more allelic variance and higher genetic diversity. All the 118 cotton varieties were divided into four subgroups by analysis of population genetic structure. There was no corresponding relation between each kind of group of materials and the geographical source. A total of 124 loci (P<0.05) and 20 loci (P<0.01) associated with mechanical harvest-related traits were detected by association analysis, with explained variance ranging from 2.23% to 14.15% and from 4.84% to 14.15% respectively. Based on the results of this study, we identified 11 typical materials, including Xi 7, Jinken 9, Y11, Yumian 18, AY-4, K2, Chaoyang 2, DZ22, Zhongmiansuo 43, C2, Guanrongchangzao B14. The elite alleles and resources can be useful for marker-assisted selection breeding.