水稲NERICA品種の農業形質に関する遺伝的要因

Genetic factors of yield related traits in lowland New Rice for Africa variety (NERICA) using different nitrogen condition and QTL to increase rice yield in lowland NERICAs were clarified. Indica Group rice variety (Oryza sativa L.) IR64 increased panicle number, culm weight and panicle weight, according to nitrogen concentration. The tendency is especially remarkable under low nitrogen concentration. NERICA‒L‒19, which is derived from a cross between IR64 and TOG5681 (Oryza glaberrima S.), showed similar values for panicle weight and culm weight, and it showed higher plant height, panicle weight and culm weight and lower harvest index than those of IR64 under all the concentrations. QTL analysis for the agronomic traits were performed using hybrid population derived from a cross between IR64 and NERICA‒L‒19. A total of 22 QTLs were detected on chromosomes (chrs.) 1 (3 QTLs), 2 (2), 4 (2), 5 (5), 6 (1), 7 (1), 8 (6) and 10 (2). Among them, 4 regions at 34.1‒36.6Mbp of chr. 1, at 23.8‒27.8Mbp of chr. 5 and at 4.8Mbp and 20.3‒28.4Mbp of chr. 8 showed several QTLs’ peaks overlapped. The regions of chr. 5 and 4.8Mbp of chr. 8 increased panicle weight by IR64 allele. Those of chr. 1 and 20.3-28.4Mbp of chr. 8 increased plant height and harvest index, respectively, by NERICA‒L‒19 allele. These results indicated that the larger panicle type of lowland NERICA is suitable under low nitrogen condition. Also, the plant type was controlled by the combination of 4 QTLs’ regions on chr. 1 and short arm of chr. 8 originated from O. glaberrima, and those of chr. 5 and long arm of chr. 8 from O. sativa Indica Group.

原著論文 (Original paper)