利用陆地棉MAGIC群体定位产量、生育期和株高性状的QTL

棉花的产量、生育期和株高是重要的农艺性状, 决定着棉花的经济效益和生产方式。为了研究这些性状的遗传基础, 利用8个亲本构建的包含960个株系的陆地棉MAGIC (multi-parent advanced generation inter-cross)群体和SSR标记对这些性状进行关联分析。对产量、生育期和株高共8个相关性状进行了3年3个地点共5个环境的田间试验。经过最佳线性无偏预测(BLUP)综合多环境的表型数据, 发现MAGIC群体比亲本有更丰富的表型变异。8个性状的广义遗传力(H ²)变化范围为0.17~0.71。结合284个SSR标记基因型数据, 利用混合线性模型对产量、生育期和株高相关性状进行关联分析, 分别检测到51、27和9个显著关联的位点, 这些位点都表现出微效性, 表明该陆地棉MAGIC群体在性状位点的挖掘方面具有高效性。检测到20个标记位点或区间控制多个性状, 还发现单株有效铃数、单铃皮棉重、第一果枝节位和株高存在染色体热点区域, 对多性状综合研究或单性状深入挖掘具有重要价值。本研究为后续深入利用MAGIC群体进行遗传研究提供参考, 一些表型优良的材料和关联到的位点为育种改良奠定了基础。

QTL Mapping for Yield,Growth Period and Plant Height Traits Using MAGIC Population in Upland Cotton

The yield, growth period and plant height are important agronomic traits that decide the economic value and planting pattern of cotton (Gossypium spp.). In order to dissect the genetic basic of these traits, an 8-way upland cotton MAGIC (multi-parent advanced generation inter-cross) population and SSR markers were used for association mapping. Eight traits of this MAGIC population were phenotyped in five environments (three years and three locations), showing wider variations than these of the founder parents. The broad-sense heritability (H ²) of the eight traits ranged from 0.17 to 0.71. Association analysis based on mix linear model was performed using 284 polymorphic SSR markers. There were 51, 27, and 9 markers significantly associated with yield, growth period and plant height traits respectively. All identified loci had minor effect for controlling the phenotypic variations, showing a higher powerful ability of the MAGIC population in association mapping. Furthermore, 20 loci were found to be associated with multiple traits acting as pleiotropism. In addition, chromosome hot spots were found for effective boll number, lint weight, first fruit spur branch number and plant height, which provided references for deeply genetically studying these loci. The elite MAGIC lines and the valuable SSR loci lay a foundation for the genetic improvement of upland cotton.