利用CSSLs群体研究稻米粒型QTL的表达稳定性

Stable Expression of QTL for Grain Shape of Milled Rice (Oryza Sativa L.) Using a CSSLs Population

利用Asominori×IR2 4的染色体片段置换系 (CSSLs)群体 ,对稻米粒长、粒宽和长宽比进行连续两年及 4个地点的QTL表达稳定性分析。结果表明 :3个性状“两年四点”的表现型都为连续分布 ,均存在超亲遗传类型 ;共检测到 13个粒型相关QTL ,其中在 8个环境中都能被重复检测到的QTL有 6个 ,即影响粒长的 qGL 3、控制粒宽的qGW 5a和 qGW 5b以及共同作用于长宽比的qLWR 3、qLWR 5a和 qLWR 5b。这 6个QTL对应置换系的相应性状与背景亲本Asominori的表现型差异在 8个环境中都达到极显著水平 (P <0 0 0 1) ,且同一QTL对应置换系相应性状的表现型在不同环境间呈显著正相关 (r≥ 0 75 ,r0 0 5=0 6 6 6 ) ,说明这 6个QTL表达稳定性较高。由于 qGL 3和 qLWR 3均位于R19 C16 77标记区间 ,qGW 5a和 qLWR 5a位于C2 6 3标记附近 ,qGW 5b和 qLWR 5b被定位在R5 6 9标记附近 ,因此R19、C16 77、C2 6 3和R5 6 9这 4个RFLP标记对优良水稻外观品质的标记辅助选择 (MAS)

A set of chromosome segment substitution lines (CSSLs),derived from Asominori/IR24 with Asominori as the recurrent parent,was planted and phenotyped for grain length (GL),grain width (GW) and length-width ratio (LWR) of milled rice in two successive years and four sites.QTL for GL,GW and LWR were characterized and stability of their expression was investigated.The phenotypic values for each trait showed a continuous distribution and some transgressive lines were also observed in the CSSLs population.Additionally,a total of 13 QTL for GL,GW and LWR were identified,and six of them were consistently detected in the eight different environments.Phenotypic values were different significantly (P<0.001) between the CSSLs harboring any of the six QTL alleles and the genetic background parent,Asominori.Significant phenotypic correlations (r≥0.75,r_(0.05)=0.67) were detected among different environments for these CSSLs carrying the same target QTL.Also,the results indicated that the six QTL,namely,qGL-3 for GL,qGW-5a and qGW-5b for GW,qLWR-3、qLWR-5a and qLWR-5b for LWR,were stably expressed in different environments.Since QTL qGL-3 and qLWR-3 were mapped in the R19-C1677 interval,qGW-5a and qLWR-5a in the vicinity of RFLP marker C263,qGW-5b and qLWR-5b near R569,the four RFLP markers,R19,C1677,C263 and R569,would be useful for further marker-assisted selection (MAS) in rice quality improvement.