Molecular Genetic Mapping of QTLs for Tiller Angle in Rice (Oryza sativa L.)

摘要

Tiller angle in rice (Oryza sativa L.) is an important morphological trait, which not only determines the plant type but also influences some factors related to photosynthesis and diseases by affecting air and light penetration. The objective of the present study was to identify quantitative trait loci (QTLs) for the tiller angle in rice using recombinant inbred (RI) lines derived from a cross between ajaponica cultivar Asominori and an indica cultivar IR24. Transgressive segregations in both directions of parents and continuous variation of the tiller angle in the RI population were observed, indicating that the tiller angle was a quantitatively inherited trait. A total of seven QTLs (qTA-2, qTA-4, qTA-7, qTA-8, qTA-9, qTA-11, and qTA-12) affectingthe tiller angle were identified and mapped on chromosomes 2, 4, 7, 8, 9, 11, and 12, respectively. Among them, qTA-9 with the largest genetic effect was detected in the interval between the XNpb108 and C570 markers on chromosome 9 where more than 27.7%~48.5% of the total phenotypic variation was attributed. The other six QTLs accounted for 4.9% -13.4% of the total phenotypic variation. In addition, the qTA-2, qTA-7, and qTA-12 alleles from Asominori increased the tiller angle, whereas the remaining four QTLs from Asominori reduced the tiller angle in rice. The identification of QTLs controlling the tiller angle may contribute to the improvement of the rice-plant type using marker-assisted selection.