四倍体小麦地方品种矮蓝麦矮秆性状的遗传分析

四倍体圆锥小麦(Triticum turgidum L.ssp.turgidum)地方品种矮蓝麦是我国重要的小麦矮秆基因资源,经鉴定其矮秆特性对外源赤霉酸敏感。2012年配制矮蓝麦与2个高秆圆锥小麦的正反交组合,2012—2013年在四川绵阳分别种植F1、F2代和F2:3家系,对株高的遗传分析表明,矮蓝麦的矮秆性状受1对隐性基因控制。利用BSA法构建高秆和矮秆池筛选多态性SSR标记,并对矮蓝麦/青稞麦F2分离群体进行连锁分析,将目标基因定位于7AS染色体上,与标记GWM471的遗传距离为2.5 c M。矮蓝麦与矮秆番麦正反交的F1和F2群体表现非常相似的株高变异特征,初步推测矮蓝麦的矮秆基因是Rht22;进一步用高通量SNP和DAr T标记对两品种进行全基因组扫描,发现二者的遗传相似性高达98.7%~99.3%。因此认为,历史上矮蓝麦和矮秆番麦可能是同一品种,是通过人为交流而传播到不同地方。矮蓝麦携带的矮秆基因在人工合成六倍体小麦遗传背景中降低株高能力中等或较弱,在育种中需要聚合其他矮秆基因而被利用。

Genetic Analysis on Dwarfing Trait in Landrace Ailanmai of Triticum turgidum L. ssp. turgidum

Ailanmai is an important Triticum turgidum ssp. turgidum landrace carrying dwarf gene in China. Its dwarfing trait was found to be sensitive to gibberellic acid. In 2012, we crossed Ailanmai with two high plant landraces, Qinkemai and Ganmai, and obtained their reciprocal F₁ hybrids. The genetic analysis was carried out in Mianyang, Sichuan Province using the F₁, F₂, and F_2:3 populations during the 2012–2013 crop seasons. One recessive gene proved to control the dwarfing trait in Ailanmai. Polymorphic simple sequence repeat (SSR) primers associated with plant height were selected through bulked segregant analysis (BSA) and used to identify the F₂ individuals. The results indicated that the dwarf gene was located on the short arm of chromosome 7A with a genetic distance of 2.5 cM from marker GWM471. We speculated Rht22 to be the dwarf gene in Ailanmai because the reciprocal F₁ and F₂ hybrids between Ailanmai and Aiganfanmai (carrying Rht22) exhibited similar distributions in plant height. This speculation was validated with high-through molecular marker analysis. The percentages of identical SNP and DArT markers between Ailanmai and Aiganfanmai were as high as 98.7% and 99.3%, respectively. We conclude that the two landraces might be the same variety a long time ago and became synonymic during their spread accompanying with humanity activities. The dwarf gene in Ailanmai had a moderate or weak effect to reduce plant height in synthetic hexaploid wheat. Thus, it should be utilized by pyramiding other dwarfing genes in wheat dwarfing breeding.