日本水稻品种越光稻米的外观品质性状的QTL遗传剖析

稻米外观品质是稻米品质的一个重要方面.是消费者选择的重要依据之一,在一定程度上影响稻米市场价格.采用一个日本优质粳稻品种越光(轮回亲本)和一个印度的籼稻品种Kasalath杂交产生的回交重组自交系(backcross recombinant inbred lines,BILs)对7个控制稻米外观品质主要性状(粒长、粒宽、粒厚、粒长宽比、垩白粒率、垩白大小和垩白度)数量性状基因位点(quantitative trait locus,QTL)进行定位分析.共检测到影响7个性状的22个QTLs,分布在8条染色体上,贡献率为5.65%～29.20%.其中在第5染色体上的R2232分子标记附近区域检测到影响4个性状的QTLs;在第3染色体上C1448和第6染色体G200分子标记附近区域分别检测到同时影响3个性状的QTLs,表明了这3个染色体区域对控制稻米外观品质性状中的有着重要作用.研究检测到的QTLs及其两侧的分子标记可以用于改良稻米外观品质的分子辅助育种.

Genetic Dissection of QTLs for the Appearance Quality in Japanese Rice Variety Koshihikari

The appearance quality is an important aspect of rice qualities, which decides the customer choice and, to some extent, affects its price in market. The study was conducted to detect quantitative trait loci (QTLs) for seven associated appearance quality traits in rice, viz., grain length (GL), grain width (GL), grain length/width ratio(LWR), grain thickness(GT), chalkiness grain ratio(CGR), chalkiness size (CS), and chalkiness degree(CD), using a backcross recombinant inbred lines (BILs) derived from the backcross between an elite japonica variety(Japan), Koshihikari (japonica), as a recurrent parent, and an indica variety(India), Kasalath. Resultantly, a total of 22 QTLs controlling the seven traits were detected and located on eight chromosomes, which could explain 5.65%-29.20% of total phenotypic variance. Interestingly, the same genomic region of QTLs tightly linked to R2232 on chromosome 5 controlled four associated the appearance quality traits, both the one tightly linked to C1448 on chromosome 3 and the one closely linked to G200 on chromosome 6 controlled affect three traits,respectively, showing that the three genomic regions have important effect on the appearance quality in rice. In a word, the QTLs detected in this study and the molecular marker linked to them can be useful for the improvement of appearance quality through the marker assisted selection (MAS) in rice. Keywords: rice grain, appearance quality trait, QTL