中国小麦微核心种质及地方品种籽粒休眠特性的分子标记鉴定

为探索我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,说明我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。

Identification of Molecular Markers Associated with Seed Dormancy in Mini 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 (Triticum aestivum L.) before harvest, but it is a complicated trait controlled by multi-genes and influenced by many environmental factors. Because seed dormancy is difficult to be accurately evaluated under field condition, molecular markers will play an important role in dormancy evaluation. In this study, four SSR markers (Xbarc57, Xbarc294, Xbarc310, and Xbarc321) on the short arm of chromosome 3A and a gene-based marker (Vp1-b2) derived from Vp-1B on 3BL were used for genotyping 138 mini core collections of Chinese wheat and landraces. The results indicated that rich alleles occurred in the five markers, and most were significantly correlated with GI value. Based on general linear model, the five markers were significantly associated with seed dormancy. Markers Vp1-b2 and Xbarc294 had stronger effects on seed dormancy than other markers, accounting for 65.8% and 61.2% of seed dormancy variation, respectively. Marker combination could promote the percentage of phenotypic variation explained, of which the combination of five markers estimated 95.9% of the GI variation, followed by the combination of Vp1-b2 and Xbarc294 (89.1%), and the combination of Vp1-b2 and Xbarc321 had the smallest estimation of GI variation (79.4%). These results indicate that seed dormancy is mainly attributed to loci Vp1-b2 and Xbarc294 on 3AS and 3BL in the 138 genotypes, and the evaluation accuracy can be enhanced by jointly application of the total five markers in markers-assisted selection.