In the crosses which 6442S was used as the female parent,the proportions of the additive effect and dominant effect showed high value,with the heritabilities ranged from 73.3% to 99.2%,and there existed polygene heritability in the crosses 6442S/Xinlu B,6442S/R402 and 6442S/1990,with the least value of 0.83% and the highest one 35.5%.
In the crosses which 1290S acted as the female parent,the genetic effect of cross 1290S/1990 was predominant on additive effect and dominant effect,whereas cross 1290S/Xinlu B on epistasis effect,and the heritabilities of the two crosses were over 94%.
In dull×sensitive combination to photoperiod, the sum of square of additive gene effect was 66.9%-84.5%, dominance was 11.6%-30.7% and epistatic gene was 1.4%-5.2% for five tested traits, which showed that additive gene effect occupied a dominate position, the role of dominance and epistatic gene effects were reduced compared with dull×dull combination.
The statistical analysis of all possible F_2 hybrids,and some of the F_2S and backcrossed genera- tions showed that husk content was a quantitatively-inherited trait, in whose expression additive gene effect played an essential part。
The results showed that: 1) the general combining ability(GCA) variations were bigger than the special combining ability(SCA) variation in the seven traits,and therefore the additional effect predominated in the traits;
With the natural content of soil nitrogen, incomplete directionally dominance of earliness over late ripening with prevalence of additive gene effect of nonallelic interactions was observed.
Although both additive and dominance components were significant for the two characters, the greater mean squares of the additive gene effect indicated its greater importance.
An additive gene effect was observed only between nonallelic minor genes U/ppl-1B and U/fpm-1B or U/tdm-1,2.
The analyses of variance and estimates of quadratic components showed that non-additive gene effects were more important in the expression of NN and PFW, whereas additive gene effect was predominant for NDW and MNW.