粳稻粒形性状的数量性状基因座检测

 【目的】通过对粳稻粒形性状的QTL检测，为粳稻粒形性状相关QTL的精细定位和分子标记辅助选择育种提供理论依据。【方法】利用大粒粳稻DL115与小粒粳稻XL005杂交获得的F2代200个个体为作图群体，在北京进行稻谷粒长、粒宽、粒厚、长宽比、千粒重等粒形性状的鉴定。采用复合区间作图法，利用SSR标记对上述粒形性状进行数量性状基因座检测。【结果】上述粒形性状在F2群体均呈正态连续分布，表现为由多基因控制的数量性状。共检测到与粒形性状相关的QTL 16个，分布于第2、3、5和12染色体上。其中qGL3a、qGW2、qGW5、qGT2、qRLW2、qRLW3、qGWT2和qGWT3对表型变异的贡献率分别为15.42%、40.89%、13.54%、33.43%、13.82%、13.61%、12.51%和10.1%，为主效QTL。其中，qGW2、qGT2、qRLW2和qGWT2均位于第2染色体上的RM12776－RM324 区间。在所检测到的16个QTL中，4个QTL的增效等位基因来源于小粒亲本XL005，而其余QTL的增效等位基因均来源于大粒亲本DL115。基因作用方式主要表现为加性或部分显性。【结论】粳稻粒形性状是由多基因控制的数量性状。第2染色体RM12776－RM324区间是分别与粒宽、粒厚、长宽比和千粒重相关的4个主效QTL的共同标记区间，与其相邻的2个标记（RM12776和RM324）应在分子标记辅助选择育种中探讨其利用价值。大粒亲本对稻谷粒长、粒宽、粒厚和千粒重等性状的增效作用显著。

Identification of Quantitative Trait Loci for Grain Traits in Japonica Rice

【Objective】 Quantitative trait loci (QTLs) of grain traits were detected to provide a theoretical basis for fine mapping and molecular marker-assisted breeding of grain traits in japonica rice. 【Method】 Using an F2 population including 200 individuals derived from a cross combination between two japonica rice DL115 with large grain and XL005 with small grain. The grain length, grain width, grain thickness, ratio of grain length to width and 1000-grain weight were evaluated in Beijing. The quantitative trait loci for above five grain traits were identified by composite interval mapping using SSR markers. 【Result】 The results showed that the five grain traits exhibited a normal continuous distribution in F2 population, indicated they were quantitative traits controlled by multiple genes. A total of 16 QTLs conferring the five grain traits were detected on chromosomes 2, 3, 5 and 12, respectively. Eight QTLs, namely qGL3a, qGW2, qGW5, qGT2, qRLW2, qRLW3, qGWT2 and qGWT3, were major QTLs and explained 15.42%, 40.89%, 13.54%, 33.43%, 13.82%, 13.61%, 12.51% and 10.1% of the observed phenotypic variance, respectively. Among them, qGW2, qGT2, qRLW2 and qGWT2 were mapped in same interval RM12776－RM324 on chromosome 2. Four QTLs alleles were derived from small grain parent XL005, and other 12 QTLs alleles were derived from large grain parent DL115. The modes of gene action were mainly additive or partial dominance. 【Conclusion】 The grain traits of japonica rice were quantitative traits controlled by multiple genes. The marker interval RM12776－RM324 on chromosome 2 was common marker intervals of four major QTLs, which were associated with grain width, grain thickness, ratio of grain length to width and 1000-grain weight, respectively. The two SSR markers, RM12776 and RM324, would be used in molecular marker-assisted breeding in japonica rice. The alleles from larger parent were showed significant effects on grain length, grain width, grain thickness and 1000-grain weight.