玉米杂交种掖单13号的SSR连锁图谱构建与叶夹角和叶向值的QTL定位与分析

Construction of a SSR linkage map and mapping of quantitative trait loci (QTL) for leaf angle and leaf orientation with an elite maize hybrid

为了增加单位面积产量,玉米育种者已经开始了更密植更紧凑株型的选育。叶夹角和叶向值是评价玉米株型的重要指标。本研究以掖478×丹340的500个F2单株为作图群体,构建了具有138个位点的SSR标记连锁图谱,图谱总长度为1394.9cM,平均间距10.1cM。利用397个F2:3家系对叶夹角和叶向值进行QTL定位分析,结果表明:叶夹角和叶向值分别检测到6和8个QTL,累计解释表型变异41.0%和60.8%,单个QTL的贡献率在2.9%～13.6%之间。与叶夹角和叶向值有关的基因主要作用方式为加性和部分显性。此外两个性状共检测到9对上位性互作位点,表明上位性互作在叶夹角和叶向值的遗传中也起较重要的作用。

Maize （Zea mays L.） breeders have begun selecting for＇more compact plants for higher density planting in order to increase yield per unit area. Leaf angle and leaf orientation are very important traits affecting maize plant type （compactness）. In this study, a genetic linkage map containing 138 simple sequence repeat （SSR） markers was constructed based on a mapping population consisting of 500 F2 individuals from the cross between inbred lines Ye478 and Dan340. This SSR linkage map spans a total of 1 394.9 cM with an average interval of 10.1 cM. Quantitative trait loci （QTL） for leaf angle and leaf orientation were identified in 397 F2：3 families. Six QTL for leaf angle were detected that could explain 41.0% of the phenotypic variation; while, eight QTL were detected for leaf orientation that could explain 60.8% of the phenotypic variation. Single QTL contribution to phenotypic variation ranged from 2.9% to 13.6%. Additive and partial dominance were the main genetic effects for leaf angle and leaf orientation; in addition, nine pairs of locus interactions were detected for the two traits, indicating that epistatic interactions at the two-loci level also play a measurable role in the genetic basis of the two traits.