Conditional and unconditional qtl mapping of grain starch accumulation in wheat | 小麦籽粒淀粉积累动态的条件和非条件QTL定位

chinois. 目的阐明影响小麦籽粒淀粉基因/QTL的时空表达和动态变化情况，为运用条件QTL更好地揭示小麦籽粒淀粉动态积累的基因表达提供参考。方法本研究以小麦品种花培3号和豫麦57构建的168个双单倍体（doubled haploid, DH）群体为材料，在6个不同的环境下种植，分别在花后12 d、17 d、22 d、27 d和32 d取样，对小麦籽粒淀粉含量（GSC）积累的条件和非条件QTL进行分析。结果在籽粒灌浆的5个时期，一共检测到7个非条件QTL和4个条件QTL，没有一个条件QTL能在测定的5个时期都有效应。7个非条件QTL分别分布在2A、3A、3B、4A、5D染色体上，其中QGsc4A在整个灌浆过程都能表达，5个时期的表型变异贡献率分别为13.57%、16.57%、21.96%、22.53%、22.90%。4个条件QTL中，QGsc4A在花后12 d、17 d、32 d均能检测到，总贡献率为21.80%，对籽粒淀粉积累的净增长量起主要作用。其它非条件QTL和条件QTL只在一个或几个阶段出现且效应值较小，花后27 d没有检测到条件QTL。结论控制GSC积累的数量性状基因以一定的时空方式表达，小麦籽粒淀粉积累的QTL动态分析，可以了解小麦籽粒淀粉积累的遗传规律及其对小麦籽粒发育的影响，为小麦产量和品质形成的分子基础的深入研究提供参考。

anglais. ObjectiveConditional QTL is a method of studying the dynamic expression of quantitative traits genes, and it was applied to better reveal dynamic expression of gene in wheat starch.MethodQTLs for developmental behavior of wheat grain starch content (GSC) were mapped using a double haploid (DH) population with 168 progeny lines, derived from a cross between two elite Chinese wheat cultivars Huapei 3×Yumai 57. GSC were evaluated at five seed filling stages (12d, 17d, 22d, 27d, and 32d after ?owering) in six different environments. This study could attain more information to understand the dynamic effects of corresponding QTLs at different developmental stages as well as the genetic information of GSC accumulation.ResultThe results showed that seven unconditional QTLs and four conditional QTLs were detected in different seed filling periods totally, but no one conditional QTL was detected in all periods. Seven unconditional QTLs were detected on chromosomes 2A, 3A, 3B, 4A and 5D, the unconditional QTL named QGsc4A persistently expressed at all seed filling stages, while unconditional QTLs of different seed filling periods could explain 13.57%, 16.57%, 21.96%, 22.53%, 22.90% of phenotypic variance respectively. Among the four conditional QTLs, QGsc4A was detected 12d, 17d, and 32d after ?owering, which accounted for 21.80% of phenotypic variation and played the most important role for the accumulation of GSC. The rest unconditional QTLs and conditional QTLs were only detected in a special or few periods, and there was no conditional QTL detected up to 27 days after ?owering. ConclusionQTL analyses were performed using a mixed linear model approach, which suggest that the QTLs express depending on different developmental stages. The present data provide new insights into understanding the genetic mechanism and regulation network underlying the development of GSC in wheat, which is beneficial to genetic manipulations for yield.