Genetic effects and environmental interactions of early maturity in short--season cotton

Nine different cotton varieties with different maturities were arranged by partial diallel crossing to form 46 combinations and then the F_(1) and F_(2) of them were planted under different ecological environments to study seven traits relating to early maturity of short-season cotton and their environmental interactions. It was shown that in short-season cotton, the seven traits relating to early maturity all presented dominating additive effect while displaying dominance effects, and epistatic effects from sowing to budding, from sowing to flowering and from budding to flowering; the early maturity traits significantly interacted with the environments. The narrow heritability of the growth period and the period from sowing to budding were higher,separately reaching 66.1% and 49.1%, and interacted weakly, while the positions of the first fruiting shoots and the period from sowing to budding had the lowest narrow heritability, separately equal to 19.8 % and 18.8 %, and their interactions with the environments reached a significant level;the heritability of the periods from budding to flowering and flowering to boll opening , and the stem heights, as well as their interactions with environments took the second place. It was accordingly revealed that the heritability of early maturity suffered strong environmental impact and thus in environmentally different locations it was not reliable to use the position of the first fruiting shoot and the period from sowing to budding as the criteria of early maturity but feasible and practicable to use growth period and flowering time as the index of early maturity.