RESUMO
A clonally propagated F2 population (F2CP), 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, rl8, 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 rl8 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.
