玉米强优势组合7个主要穗部性状在3种环境下的QTL分析

摘要

玉米产量是遗传基础复杂的数量性状.利用玉米(Zea mays L.)单交种烟单14号杂交组合的F1(Mol7×黄早四)自交后形成的191个F2单株作为构图群体,构建了由扩增片段长度多态性(AFLP)和简单重复序列(SSR)两种标记组成的遗传图谱.F2继续自交衍生的184个相应F2∶3家系用于玉米7个穗部性状表型的田间鉴定.采用以混合线性模型为理论基础的复合区间作图法和配套软件QTLmapper、V2.0,在3个环境下共检测到76个穗部性状的数量性状基因座(QTL).其中穗粒重、穗重、出籽率、穗长、秃尖长、穗粗和轴粗的QTL数目分别为8、8、11、10、9、10和20个.大多QTL仅在单一环境下被检测到,单个QTL解释的表型变异率很低,仅有5个QTL的加性效应贡献率大于10％,绝大多数QTL显性效应贡献率小于1％.基因作用方式29％的QTL为加性,47％为部分显性,11％为显性,13％为超显性.控制玉米穗部性状的QTL在染色体间分布不均匀,且呈现成簇分布、毗邻分布等特征.各个QTL位点上起增效和减效作用的等位基因在双亲间分布不均匀,两个亲本均可以提供增效或减效等位基因.本研究结果对于玉米高产分子育种中分子标记辅助选择(MAS)和亲本选配等问题具有启发和指导作用.%Maize yield is quantitative trait with complex genetic basis. Used 191 F2 individuals derived from the cross Yandanl4 of maize {Zea mays L.), Mo17×Huangzao4 as genotype, the linkage map was constructed with simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP ) markers 184 corresponding F2:3 families were phenotyped for 7 main ear traits of maize in three environments. A mixed linear model approach and its software, QTLmapper/V2.0, were used to detect quantitative trait loci (QTLs) controling 7 ear traits. 76 QTLs in three environments, including 8 kernel weight per ear QTLs, 8 ear weight QTLs, 11 kernel product percent QTLs, 10 ear length QTLs, 9 bare tip length QTLs, 10 ear diameter QTLs and 20 axis diameter QTLs, were detected totally. Most QTLs were detected in only one environment. The phenotypic variation explained by single QTL was very small. There were only 5 QTLs with the phenotypic variation explained by additive effect of more than 10%, and most QTLs with the phenotypic variation explained by dominance effect of less than 1%. The percentage of 76 QTLs with the gene action model of additive , part dominance, dominance and over dominance were 29%,47%, 11% and 13% , respectively. The QTLs of ear traits in maize had the distribution characteristics of not uniform, clustered and adjacent in chromosome. The increased-effect allele and the decreased-effect allel on these QTLs were not well-uniform between two parents. Any part could provide the increased-effect or decreased-effect allel. The results of this study will be heuristic and instructive for molecular marker assisted selection (MAS) and parent selection etc in high yield molecular breeding of maize.