[Genetic analysis on flowering and boll setting in upland cotton (Gossypium hirsutum L.). III. Genetic behavior at different developing stages].

An additive-dominant genetic model with genotype by environment interaction was employed to analyze the genetic behavior of flowering and fruiting at different development stages, with 2-year data from 4 x 4 diallel crosses. The results of variance analysis indicated that flowering and fruiting behaviors were mainly controlled by dominant effects at early period, but by additive effects later on. Compared with genetic main effects, GE interaction effects playeda minor role on the flowering and fruiting behavior. The analysis of covariance between average flower number, boll number at different development stages and total number of bolls showed that there were significant positive dominant correlation and negative or zero additive correlation before August 1st, but having the opposite results afterward. Interaction correlation existed during the whole period. It was found, by further analysis of conditional variances, that different development stages have diverse gene action intensity. The last ten days of July and the first-middle ten days of August had the highest gene action level. Time interval of investigation played a great role on exploring the law of gene action during the flowering and fruiting period; when selecting the time interval of investigation, it is necessary to contemplate the purpose of the experiment, environmental condition, investigating traits and developing period simultaneously.