大豆杂种产量相关的位点及等位变异分析

选用来源于中国黄淮和美国的熟期组II~IV的8个大豆品种, 按Griffing方法II设计, 配成28个双列杂交组合, 包括8个亲本共计36份材料。选用300个SSR标记, 对8个大豆亲本进行全基因组扫描, 利用基于回归的单标记分析法, 对大豆杂种产量和分子标记进行相关性分析, 估计等位变异的效应和位点的基因型值, 剖析杂种组合的等位变异。结果表明, 300个SSR标记中有38个与杂种产量显著相关, 分布于17个连锁群上, 其中D1a和M等连锁群上较多, 有8个位于连锁定位的QTL区段内(±5 cM)。单个位点可分别解释杂种产量表型变异的11.95%~30.20%。杂种的位点构成中包括有增效显性杂合位点、增效加性纯合位点、减效加性纯合位点和减效显性杂合位点4部分, 其相对重要性依次递减。从38个显著相关的SSR标记位点中, 遴选出Satt449、Satt233和Satt631等9个优异标记基因位点, Satt449~A311、Satt233~A217和Satt631~A152等9个优异等位变异, 以及Satt449~A291/311、Satt233~A202/207和Satt631~A152/180等9个优异杂合基因型位点。这些结果为理解杂种优势的遗传构成和大豆杂种产量聚合育种提供了依据。

Analysis of Loci and Alleles Associated with Hybrid Yield in Soybean

Single marker regression analysis is a effective way to detect differences among genotypes associated with marker alleles in quantitative traits. Eight soybean parental materials, seven from Huang-Huai region in China and one from US with maturity group II–IV, were used to develop a set of diallel crosses according to Griffing’s Method II, including the eight parents and their twenty-eight crosses. The molecular data of 300 SSR markers on eight parental materials were obtained and analyzed for association between SSR markers and hybrid yield using the single marker regression analysis. The hybrid crosses were dissected into their allele constitution and the effects of alleles and genotypic values of single locus were estimated. The results showed that 38 SSR loci located on 17 linkage groups were identified to associate with hybrid yield in the diallel crosses with more loci on linkage groups D1a, M, etc., and eight of the 38 loci were located within a region of ±5 cM apart from a known QTL identified from family-based linkage (FBL) mapping in the literature. Each of the loci explained 11.95%–30.20% of the phenotypic variance of hybrid yield. The allele pairs of the hybrids were composed of four parts, i.e. positive dominant heterozygous loci, positive additive homozygous loci, negative additive homozygous loci and dominant heterozygous loci, with their relative importance in a descending order. Among the 38 loci associated with hybrid yield, nine elite loci such as Satt449, Satt233 and Satt631 and nine elite alleles such as Satt449–A311, Satt233–A217 and Satt631–A152 were identified. Meanwhile, nine heterozygous allele pairs such as Satt449–A291/311, Satt233–A202/207 and Satt631–A152/180 were detected. These results will provide some relevant information for understanding the genetic basis of heterosis and lay a foundation for hybrid soybean breeding by design.