Analysis on combining ability and heritability of main agronomic traits in two-line indica hybrid rice

The combining ability and heritability of 11 main agronomic traits in two-line indica hybrid rice were synthetically studied based on NCⅡ mating design by using 10 newly developed photo-thermo-sensitive genic male sterile rice(PTGMS) and 3 elite restorers.The results were as follows: ① Both additive and nonadditive effects were significant in 11 agronomic traits except panicles per plant(PP),1000-grain weight(TGW),grain weight per plant(GWP) and relative daily grain yield(RDGY) in which nonadditive effects were insignificant.The additive effect was principal in all traits,however,nonadditive effects was also considerable in panicle length(PL),seed density (SD) and spikelets per panicle(SP).② Of all 11 agronomic traits in F_1,most of them were influenced more greatly by PTGMS than restorer lines,except plant height(PH),SP and TGW,which were influenced more greatly by restorer lines than PTGMS.③ Based on synthetically analysis on combining ability,the results showed that 208S,02-142 and Peiai 64S were excellent in 10 tested sterile lines,and it was possible to use them and obtain some super hybrid rice by screening large numbers of combinations;the best restorer line was Yangdao 6,then E32 and Ning 108.④ The order of H~2_N() in 11 agronomic traits was: days from sowing to heading(DSH)PHseed setting rate(SSR)fi11ed spikelets per panicle(FSP)RDGYTGWPLSDSPGWPPP.