Study on Heterotic Distribution of Main Characters of Transgenic Bt Cotton

The heterosis and genetic expression in 73 hybrids of transgenic Bt cotton were analyzed .The result showed: (1)The heterosis of lint yield before frost,plant height,bollweight,lint percentage and rate of blossom before frost were obvious.(2) The distribution of the useful heterosis per character have a different range.That of lint yield of 56%combinations concentrate in 10.1~35%.The useful heterosis of total yield,boll weight,lint percent index and rate of blossom before frost were 0.1~15%.But that of growth duration and 2.5% span length in the hybrids were inferior with the average of 0.1%~5%.(3) The heterosis of main characters in F 2 hybrids except for 2.5% span length and seed index were reduced compared to that of F 1 hybrids. The total yield, lint yield before frost, bolls per plant have the lowest heterosis , boll weight, lint percent and seed index have the highest heterosis.