Genetic Analysis of Floral Characters in A DH Population Derived from An indica/japonica Cross of Rice

The behavior of floral characters is one of the important factors influencing outcrossing and hybrid yield in seed production of rice hybrid.By using a DH population derived from a rice indica/japonica cross,genetic analyses of floral characters,such as percentage of exserted stigmas,stigma length,stigma width,style length,anther length,anther width,spikelet length,spikelet width,length-width ratio of spikelet,and panicle exsertion degree,were conducted in the present study.There were highly significant differences (P<0.01) among genotypes in the DH population for all of the studied traits regardless of marked difference or no difference between the two parents for the traits.All of the traits showed continuous variation and large aggressive segregation.Anther width had a relatively lower heritability of 50% and the number of genes involved in the trait was estimated to be up to 13,while for other 9 traits the heritabilities and gene numbers were estimated to be 68%-93% and 7-10,respectively.These results suggested that all of these traits were quantitatively inherited and that the two parents had their different positive alleles for the traits which could be recombined to produce more superior genotypes.Except stigma length,stigma width and panicle exsertion degree,significant complementary gene interactions for other 7 traits were detected.Phenotypic correlation and path analysis revealed that the floral traits such as stigma length,stigma width,and length-width ratio of spikelet were most highly associated with stigma exsertion percentage.The genotypes with high stigma exsertion percentage appeared to have long stigmas,long grains and long styles.Anther length and width were less associated with stigma exsertion percentage.For panicle exsertion degree large variations were observed in the DH population,but no gene interaction was detected,implying the additive effects as the genetic main effects for the trait.