[O31] Temperature Stress

[O31-06] Genetic Variation of Spikelet Sterility Induced by Typhoon in Introgression Lines with Genetic Background of an Indica Group Rice (Oryza sativa L.) Variety IR 64

(Invited Speaker)

^○Asami Tomita^1,2, Md. Nashir Uddin³, Mitsuhiro Obara⁴, Hiroki Saito¹, Yoshimichi Fukuta¹ (1.Tropical Agriculture Research Front, Japan International Research Center for Agricultural Sciences, Japan, 2.Graduate School of Environmental and Life Science, Okayama University, Japan, 3.School of Health and Life Sciences, North South University, Bangladesh, 4.Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural Sciences, Japan)

Wide genetic variations for degrees of spikelet sterility induced by typhoon and days to heading (DH) were found among 317 introgressions lines (INLs) derived from crosses between new plant type varieties and an Indica Group rice, IR 64. The sterility was induced by continuous dry wind after several days from panicle heading of rice plant, and the variation for degrees of spikelet sterility (SS) among the 194 INLs from 83 to 86 days of DH were also observed. The SS showed positive correlations with culm length (CL), panicle length (PL), panicle weight (PW) and PW/total weight [TW: culm and leaf weight (CW)+PW)], but not with CW and panicle number (PN). Based on these variations, the 194 were classified into three groups; A1, A2 and B. SS, CL, PL, PW and CW of group A1 were the lowest values among them, and those of B were the highest. PN of B was higher than those of the others, significantly. A total of seven quantitative trait loci (QTL) for SS were detected on chromosomes (chr.) 1, 2, 4, 7 (two QTLs), 8 and 11. Among them, those of chrs. 2, 4, 7 and 11 were located in the same regions with the other QTLs for PW/TW and PN, DH, CL, PL, CW and PN, CL and PW/TW, and DH, CL and PN, respectively. These results indicated large plant architecture with large panicle, high plant height or high tiller, increased SS. The relationships among traits, and QTLs detected will be useful information for genetic improvement of tolerance to typhoon damage in rice.