利用DH和IF_2两个群体进行小麦粒重、粒型和硬度的QTL分析

Detection of QTL for Kernel Weight, Grain Size, and Grain Hardness in Wheat Using DH and Immortalized F_2 Population

【目的】检测控制小麦粒重、粒型和硬度加性和显性QTL,解释控制这些性状的分子遗传基础。【方法】以小麦品种花培3号、豫麦57构建的包含168个株系的DH群体和由其构建的包含168个株系的IF2群体为材料,结合含有368个位点的分子遗传图谱,对5个环境的DH群体以及2个环境的IF2群体的千粒重、粒型和硬度数据进行QTL分析。【结果】共检测到控制千粒重、粒长、粒径和硬度的35个加性效应和18对上位效应QTL,包括控制千粒重的8个加性效应位点以及5对上位性位点,控制粒长的10个加性效应位点以及6对上位性位点,控制粒径的10个加性效应位点以及6对上位性位点,控制硬度的7个加性效应位点以及1对上位性位点。其中,控制粒重的Qtkw6A在DH和IF2群体中都能检测到,而且既有加性效应又有显性效应,加性效应的贡献率在2个群体内分别为9.39%和11.75%,显性效应的贡献率为1.37%。控制粒径的Qgd6A也在DH和IF2群体中检测到,加性效应贡献率分别为15.02%和15.03%,而且与控制粒长的Qgl6A为同一基因位点,在DH和IF2群体中对粒长的加性效应贡献率分别为14.96%和15.10%。【结论】小麦的千粒重和粒型的遗传主要受加性效应控制,同时也受上位效应影响。硬度主要受位于5D染色体短臂上一个主效基因控制,同时受其它微效基因以及上位性影响。本研究检测到的一些重要QTL可用于相关性状的分子标记辅助选择育种,用IF2群体检测到的显性效应QTL及具有显性×加性、加性×显性及显性×显性效应的QTL可为有关性状杂种优势的研究提供参考。

[Objective] Grain weight （GW）, grain size （GS）, and grain hardness （HD） are important complex traits in wheat, which are determined by quantitative trait loci （QTLs）. In this study, to attain more genetic information ofGW, GS, and HD in wheat, QTLs with additive effects and dominant effects for these traits were detected. [Method] Based on a genetic linkage map contains 368 sites, QTLs for GW, GS, and GS were evaluated in five different environments by using a doubled haploid （DH） population lines derived from a cross between two elite Chinese wheat cultivars Huapei 3/Yumai 57 （Triticum aestivum L.） and in two different environments by using an immortalized F2 population generated by randomly permutated intermating of these DHs. [ Result] A total of 32 additive QTLs and 18 pairs of epistatic QTLs were detected, including 8 additive QTLs and 5 pairs of epistatic QTLs for 1000-kernel weight, 10 additive QTLs and 6 pairs of epistatic QTLs for grain length, 10 additive QTLs and 6 pairs of epistatic QTLs for grain diameter, and 7 additive QTLs and 1 pair of epistatic QTLs for grain hardness. The QTL Qtkw6A for GW was persistently expressed in both of DH and IF2 population, and the contributions of additive effect in the two population were 9.39% and 11.75%, respectively, and 1.37% for that of dominance effect. The QTL Qgd6A for grain diameter was persistently expressed in both of DH and IF2 population, and the contributions of additive effect in DH and IF2 population were, respectively, 15.02% and 15.03%, It was the same as the QTL Qgl6A, the contributions of additive effect in DH and IF2 population were, respectively, 14.96% and 15.10%. [ Conclusion ] The results showed that both additive effects and epistatic effects were important genetic bases of GW and GS. Grain hardness is mainly controlled by a major gene located on the short arm of chromosome 5D, and is also influenced by other minor genes and epistatic effects. The QTL detected in this study could be used in MAS. The QTL with dominance effect and those with interactions between dominance and additive, additive and dominance, dominance and dominance detected by IF2 population would provide assistance for the study on heterosis.