一个水稻卷叶主效QTL的定位及其物理图谱的构建

One Major QTL Mapping and Physical Map Construction for Rolled Leaf in Rice

以水稻平展叶品种奇妙香和中度卷叶品种91SP068组合的F2无性系群体为定位群体,利用微卫星标记(SSR)对卷叶基因进行定位。在第5染色体长臂上定位到1个卷叶主效QTLs(rl8),它来自亲本91SP068,两侧标记为RM6954和RM6841,标记间的遗传距离为3.8cM,rl8距RM69541.0cM。所估计的加性效应和显性效应两年间均有所不同,2002年和2003年通过复合区间作图法所估计的加性效应分别为9.61和6.23,显性效应分别为- 1.19和-4.44,两年间对表型的贡献率变化在20%～33%。同时,构建了覆盖该QTL区间的物理图谱,两标记间的物理距离为542kb,遗传距离和物理距离之比为144kb/cM。

A clonally propagated F_2 population(F_2CP),derived from the rice cross of Qimiaoxiang/91SP068,was used to map rolled leaf QTLs.As the parent Qimiaoxiang is an unrolling leaf variety,while 91SP068 is a medium rolling variety with about 34% rolling index.One major QTL,rl_8,which came from 91SP068,was mapped between two flanking SSR markers,RM6954 and RM6841,on chromosome 5,with genetic distance 3.8 cM,and was 1.0 cM away from RM6954.Its additive effect estimated by composite interval mapping(CIM) was 9.61 in 2002 and 6.23 in 2003,and the dominance effect was also different between two years,-1.19 in 2002 and (-4.44) in 2003,respectively.It explained about 20%~33% of the total phenotypic variation between two years.Furthermore,an integrated physical and genetic map encompassing rl_8 region was constructed,and the physical distance of the interval was 542 kb,and the ratio of physical to genetic distance was 144 kb/cM.Based on this research,fine mapping of rolled leaf QTLs will not only facilitate the map-based cloning of the gene itself,but also improve the efficiency of marker-assisted selection in plant breeding.