Identification of Molecular Markers Associated with Seed Dormancy in Micro-core Collections of Chinese Wheat and Landraces

Seed dormancy evaluated by germination index (GI) is often regarded as a main and pivotal component of observed genetic variation for pre-harvest sprouting (PHS). Improving seed dormancy can decrease or avoid PHS damage to wheat before harvest. However, it is difficult to accurately evaluate seed dormancy under field conditions. In this study, 4 simple sequence repeat markers (Xbarc57, Xbarc294, Xbarc310, and Xbarc321) on the short arm of chromosome 3A and a gene-based marker (Vp1-b2) on 3BL were used for genotyping 138 micro-core collections of Chinese wheat and landraces. Rich alleles were detected using these markers, and most of them were significantly correlated with GI value. A significant association between the 5 markers and seed dormancy was found according to General Linear Model. Vp1-b2 and Xbarc294 had larger effects on seed dormancy than other markers, which accounted for 65.8% and 61.2% of phenotypic variation, respectively. Combination of the 5 marker gave the largest estimation of GI variation in the 138 wheat genotypes (95.9%), followed by marker combination Vp1-b2/Xbarc294 (89.1%), and marker combination Vp1-b2/Xbarc321 had the smallest effect (79.4%). This result indicated that seed dormancy of tested genotypes was mainly associated with 2 loci on 3AS and 3BL.

摘 要为探索中国小麦微核心种质及地方品种籽粒休眠的遗传基础, 利用已报道的4个3AS上的SSR标记(Xbarc57、Xbarc294、Xbarc310和Xbarc321)和1个3BL上的Viviparous-1基因标记Vp1-b2对107份我国小麦微核心种质及31份地方品种进行籽粒休眠的分子标记鉴定。结果表明, 5个分子标记在试验材料中表现出丰富的等位变异, 具有5∼6种等位类型, 与籽粒萌芽指数(GI)密切相关。根据一般线性模型分析结果, 各位点的等位变异显著影响籽粒休眠, 其中Vp1-b2和Xbarc294对籽粒休眠作用较其他标记大, 可分别解释65.8%和61.2% 的表型变异; 其次是Xbarc310(56.3%)和Xbarc57(55.8%), 最小的是Xbarc321(53.3%)。而5个标记联合可解释95.9% 的性状变异, 其次是Vp1-b2和Xbarc294的组合(89.1%), 解释变异最小的标记组合是 Vp1-b2和Xbarc321(79.4%)。5个分子标记即可解释籽粒休眠的绝大部分表型变异, 说明中国小麦微核心种质及地方品种籽粒休眠特性受3AS和3BL上的2个主效基因控制。