Analysis of combining ability of main agronomic characters of Bt gene in hybrid rice

Combining ability and heritability of 8 agronomic characters were analyzed with an 8×8 incomplete diallele cross design,including 8 CMS lines and 8 restorer lines of Bt gene.The results showed that grain numbers per panicle were a main factor affecting grain yield of hybrid rice.The general combining ability(GCA) of main agronomic characters of the lines R8,A7 and A5 were higher than others,they were optimum for hybrid parents.The values of the special combining ability(SCA) of most main agronomic characters was positive for combinations of A7/R8,A5/R8,A5/R2,A5/R7,A7/R6,which suggesting their heterosis could be employed in hybrid rice breeding.The heritability analysis showed that 1000gain weight,total grain numbers per panicle,plant heights,panicle length,grain weights per plant were controlled by gene additive effect;whereas grain number per plant,panicles per plant were controlled by not only gene additive effect,but also controlled by dominant effect and epistatic effect.