中国小麦地方品种籽粒强休眠特性的主效基因鉴定

前人研究表明,我国一些小麦地方品种籽粒休眠性强,穗发芽抗性好,可能受1～2对主效基因控制.本文利用小麦(Triticum aestivum)2个重组自交系群体(RILs,万县白麦子/京411,万县白麦子/中优9507)进行2点4年的田间试验,以期发掘控制我国小麦地方品种(万县白麦子)籽粒休眠的主效QTL位点.通过复合区间作图进行分析,分别在3AS和3BL染色体上鉴定出2个主效QTL,前者分布在Xbarc57和Xbarc294标记区间(在2个RILs群体中遗传距离分别为5.8和8.5 cM),在多年多点的实验中可解释25.6%～48.3%的表型变异;后者分布在Vp1和Xwmc446标记区间,在万县白麦子/中优9507群体中的遗传距离为8.1 cM,可解释23.5%～37.8%的表型变异.上述研究表明,我国小麦地方品种万县白麦子籽粒强休眠特性主要受Osd.ahau-3A、Qsd.ahau-3B这两个主效基因控制,在不同环境中表现出较好的遗传稳定性.可通过聚合育种的方法获得籽粒休眠性强、穗发芽抗性好的小麦新品种.

Investigation of Main Loci Contributing to Strong Seed Dormancy of Chinese Wheat Landrace

Many Chinese wheat landraces appear typically strong seed dormancy and pre-harvest sprouting (PHS) tolerance, which are presumed to be controlled by one or two main genes. In this study, we tried to investigate the genetic basis for strong seed dormancy of wheat (Triticum aestivum) landrace, Wanxianbaimaizi, using two recombinant inbred line (RIL) populations from the crosses of Wanxianbaimaizi/Jing 411 and Wanxianbaimaizi/ Zhongyou 9507, respectively. The populations were genotyped with 1 754 SSR markers and a gene-marker (Vpl-b2). By analyzing the data of grain dormancy covering two sites and four years, two major QTLs were detected using composite interval mapping, one was on chromosome 3AS flanked by Xbarc57 and Xbarc294 with linkage distances of 5.8 cM and 8.5 cM in the two populations, and the other on 3BL linked to Vpl and Xwmc446 with the distance of 8.1 cM. The two QTLs were designated Qsd.ahau-3A and Qsd.ahau-3B, which explained 25.6% ～ 48.3% and 23.5% ～ 37.8% of phenotypic variation in the two mapping populations across four environments, respectively. These results demonstrated that the long period seed dormancy of Wanxianbaimaizi is due to the two loci with good stability in varied environments; Therefore, it is possible to obtain strong seed dormancy and resistance to PHS in white wheat cultivars by pyramiding the two major genes.