一个新的水稻苗期耐碱主效QTL的定位

Mapping of a New Major QTL for Alkaline Tolerance at Seedling Stage in Rice

苗高是水稻生长发育的重要指标,碱胁迫会使水稻苗高明显降低。本研究以碱敏感的粳稻品种彩稻为母本与强耐碱的籼稻品种WD20342为父本杂交衍生的F2:3群体为初定位作图群体,构建了包含151个SSR标记的遗传连锁图谱;在0.15%Na2CO3胁迫条件下,对水稻苗期的苗高进行QTL初步定位。共检测到3个与碱胁迫下苗高相关的QTL,分布在第5、7和11染色体上,其中q ASH-7的贡献率最大,为20.09%,是一个主效QTL。以彩稻为轮回亲本进行分子标记辅助选择回交,构建了BC2F2:3次级定位群体,在初定位区间进行SSR标记加密,将q ASH-7定位在第7染色体RM336~RM5495遗传距离0.9 c M、物理距离180.67 kb的区域内,共预测出23个编码基因。本研究结果为水稻苗期苗高QTL更加精细的定位以及图位克隆提供了研究基础。

Seeding height is one of important factors affecting the development of growth in rice. In this study, we analyzed and located quantitative trait loci(QTLs) for seeding height at seedling stage in rice under alkali stress(0.15% Na-_2CO_3solution) by using an F_(2:3)population, which derived from a cross Caidao(Japonica) as the maternal parent and WD20342(Indica) as the paternal parent with 151 microsatellite markers. A total of 3 QTLs associated with seeding height at seedling stage under alkaline stress were detected, which located on chromosome 5, 7, and11, respectively. q ASH-7 is a major QTL that explained 20.09% of the observed phenotypic variation. We added the microsatellite marker among the interval of initial. Then, q ASH-7 was narrowed to the physical distance of180.67 kb(genetic distance of 0.9 c M) and flanked between RM336 and RM5495 by using an BC_2F_(2:3)population,which derived from a cross between Caidao as recurrent parent and WD20342 as the donor parent, in this region,23 candidate gene were detected. These results should have an important significance for positional clone and molecular breeding in alkaline resistance related genes in rice.