The results showed that plant traits of 1781,1778,1779,1768,1766 were higher in SCA,on the whole,and the yield trait of 1794,1792,1787,1777 was higher in SAC.

The general combining ability(GCA)and special combining ability(SCA)of seven characters were analyzed in a design of incomplete diallel cross(P1 P2)of seven parent materials.

The objective of this study was to determine combining ability(GCA and SCA) of grain yield and whole growth period,and yield heterosis of 20 rice populations.

Further analysis have been done (about) general combining ability ,special combining ability ,total combining ability on the basis of above.

The results show that population means of six agronomic and economic characters were significant different,variances of general and special combining ability were very signifcant.

The general combining ability (GCA), special combining ability (SCA) and genetic parameter of main quantitative characters were analyzed.

Correlations between specific combining ability,heterosis and genetic distance in hybrid rice

Both general combining ability(GCA)and specific combining ability(SCA)of all the characteristics were significant at 1% level except for the number of panicles per plant,in which the SCA was not significant.

Five photosensitive,widely compatible paddy rice varieties and 4 upland varieties were crossed in a p×q partial diallel cross experiment,the combining ability of 9 main agronomic traits of the F_1s were analyzed,and the general combining ability effect of the parent varieties and the specific combining ability effect of the cross combinations were calculated.

With the material of 6 CMS lines, 7 restorer lines and 42 hybrid combinations, the GCA and VAR of SCA of yield traits, quality traits and bearing date were analyzed.