Mapping of QTLs for leaf developmental behavior in rice (Oryza sativa L.)

Leaf developmental behavior in rice ( Oryza sativa L.) is one of the important agronomic characteristics, which not only determines vegetative growth but also influences grain yield. This study was conducted to identify quantitative trait loci (QTLs) for total number of leaves (TNL), days to the emergence of flag-leaf (DEF) and the leaf emergence rates (LER) on main stem, which mainly represent leaf developmental behavior, using recombinant inbred lines (RILs) derived from a cross between a japonica variety, Asominori and an indica variety, IR24, cultivated in 2001 and 2002. The transgressive segregations in both parental directions and continuous variations of all three tested traits were observed. Significant correlations among these traits were detected. A total of fourteen QTLs for leaf development behavior were detected with 289 RFLP markers. Six QTLs controlling TNL were mapped to chromosomes 3, 5, 6, 8, 9, 12, and accounted for 5.6similar to15.7% of the total phenotypic variations, and three QTLs for DEF were mapped to chromosome 3, 6, 8 and accounted for 10.7similar to35.4% of total phenotype variation and five QTLs for LER were mapped to chromosome 1(two QTLs), 2, 4, 9 and explained 6.2similar to17.5% of phenotype variation. The identification of QTLs for leaf developmental behavior in rice may be useful for selection of 'fast growing genotype' before heading using maker-assisted selection.