不同环境下多个玉米穗部性状的QTL分析

摘要

[Objective] As ear traits have a significant correlation with maize yield, genetic dissection of ear traits under different environments will be beneficial to marker-assisted breeding in high-yielding maize hybrids and future basic research.[Method] Four ear traits including ear length (EL), ear diameter (ED), kernel number per row (KRE) and grain weight per ear (GW), were investigated using two sets of F2:3 populations, which were derived from crosses of Y478×Huangzaosi (Y/H) and Q319×Huangzaosi (Q/H), respectively. The two populations were evaluated in three locations, i.e. Beijing, Henan and Xinjiang, in 2007 and 2008. Quantitative trait locus (QTL) analysis was then conducted to understand their genomic locations and gene effects.[Result] Totally 33 and 46 QTLs were detected in single-environment analysis for Y/H and Q/H, respectively, which were mainly distributed on chromosomes 4, 5, 6, 7 and 10. Furthermore, it was found that four and six QTLs detected in different environments for the two populations respectively, were located in the same genetic regions and were not significant interaction with environment in multiple-environment joint analysis. The largest phenotypic contribution was from qGW1-4-1 on chr. 4 and qKRE1-5-1 on chr. 5 in Y/H, all with the phenotypic variation explained of more than 10％ in the detected environments, and from qKRE2-3-2 and qED2-2-1 in Q/H, with the phenotypic variation explained of 7.23％ to 18.3％ and 7.1％ to 15.6％, respectively. In multiple-environment joint analysis, two and six QTLs, which had significant interaction with environment, were detected in Y/H and Q/H, respectively, and the number of QTLs for GW interacting with environment was the most. The results of epistasic analysis indicated that only a few significant QTL presented epistasis, and most of the interactive loci did not link to any detected QTLs. Comparison of the results in the two F2:3 populations, four congruent QTLs were identified for GW and KRE in bin1.10, bin5.05, bin6.05 and bin7.02,respectively. [Conclusion] Those genomic regions detected in different environments and genetic backgrounds could be useful in marker-assisted selection and future fine mapping and positional cloning. However, more attention should be paid to the effects of environments or epistasis.%[目的]探讨穗部性状之间的相互关系及其遗传机制.[方法]以优良玉米自交系黄早四为共同亲本,分别与掖478和齐319杂交,构建两套F2:3群体为研究材料(分别缩写为Y/H和Q/H),在2007年和2008年分别在北京、河南、新疆等3个地点共6个环境下进行了穗长、穗粗、穗行数和穗粒重4个性状的表型鉴定,采用单环境分析和多年多点的联合分析方法对其进行了数量性状位点(QTL)分析.[结果]在单环境分析中,2个群体分别检测到33个QTL和46个QTL,主要分布在第4、5、6,7、10染色体上.进一步分析发现,在Y/H群体中共定位到4个环境钝感的QTL(印在2或2以上环境下均能被检测到的QTL,且在联合分析中与环境无互作效应),其中以位于第4、5染色体上的qGW1-4-1、qKRE1-5-1对表型的贡献率最大,在不同的环境中对表型的贡献率均大于10%;在Q/H群体中共定位到6个环境钝感的QTL,其中以qKRE2-3-2、qED2-2-1对表型的贡献率最大,分别解释7.23%-18.3%和7.1%-15.6%表型变异.通过多个环境的联合分析,Y/H和Q/H群体分别检测到2个和6个QTL与环境存在显著互作,且以穗粒重与环境互作的QTL最多,而其它性状的大部分QTL与环境的互作效应不显著.上位性分析结果表明,只有少数几个显著QTL位点参与上位性互作,而大部分上位性QTL为非显著位点闻的互作,对表型的贡献率较小.比较分析2个群体的QTL定位结果,在2个群体间共检测到4对共有QTL,分别与穗粒重和德行数相关,位于bin1.10,bin5.05、bin6.05和bin7.02.[结论]这些在不同环境或不同遗传背景下检测到的QTL,可作为穗部性状改良的候选染色体区段,用于分子标记辅助选择或图位克隆,但是同时也要注意上位性和环境对它们的影响.