陆地棉早熟基因来源的遗传分析

棉花早熟性相关的性状多为复杂的数量性状，是由多个基因和环境共同作用的结果，其遗传基础研究比较困难。利用连锁作图和关联分析方法，对目标性状进行基因定位，找出与性状相关联的位点，为解析复杂性状的基因来源提供了新的手段。本文分别以早熟亲本新陆早8号和新陆早10号为母本，以陆地棉标准系TM-1为父本构建F₂作图群体，利用在亲本间筛选出的多态性SSR引物，通过JoinMap 3.0软件构建了2张遗传图谱，以Win QTLCart 2.5复合区间作图法在F₂~F_2:3中定位到控制全生育期、苗期、蕾期、花铃期和霜前铃数等早熟性相关性状的37个QTL。控制早熟性的有利等位基因多来自早熟祖先611波和金字棉。多数性状在两类材料中由不同的基因控制，且以加性遗传为主。在由43个陆地棉品种材料构成的自然群体中通过关联分析检测到54个与这些早熟性相关性状极显著关联的位点。研究表明连锁作图和关联分析的检测结果具有较高的可比性。本研究为早熟陆地棉聚合改良以及分子标记辅助育种打下了基础。

Analysis of Early Maturity Gene Sources in Upland Cotton Using Molecular Markers

The traits related to early maturity in upland cotton are quantitative traits usually affected by multiple genes and environments, it is difficult to dissect their genetic basis. However, both linkage mapping and association analysis provide new tools toward interpreting the gene sources of complex traits. In this study, two F₂ mapping populations were constructed by using upland genetic standard line TM-1 as male to cross with female parents Xinluzao 8 and 10, respectively. Thirty-seven QTLs for traits related to early maturity were identified by the composite interval mapping (CIM) method of Win QTLCart 2.5 in the F₂–F_2:3 of the two mapping populations_. Positive alleles at these loci were mostly from early maturity ancestor 611-B and King cotton, respectively. In addition, most of the traits were controlled by different genes in the two sets of gene pools, showing primarily additive effects. Furthermore, in a natural population consisting of 43 different Upland cotton cultivars, 54 genetic loci significantly associated with early maturity related traits were detected through genome-wide association analysis, showing great comparability with the linkage mapping results. Our study provided insights into the genetic bases of early maturity and laid a foundation for early maturity gene pyramiding and marker-assisted selection of upland cotton.