Four indica sterile lines (A) and corresponding maintainer lines (B) as well as five indica restorer lines, which varied in panicle dry weight, were used to create genetic populations of two generations according to incomplete diallel cross design (4 x 5). Analysis on panicle dry weight at different developmental stages based on tow-years experimental data was conducted by using additive-dominant developmental genetic models with genotype effects and genotype x environment interaction effects. The results showed that panicle dry weight was controlled by both genetic main effects and genotype x environment interaction effects in the whole developmental process. During the early-middle developmental periods (15 days after flowering), panicle dry weight was mainly governed by dominant effects, and dominant genes expressed with large amount. The meanwhile, positive effects produced by environmental factors appeared to be significant. Proper cultivation measure to create good external environment conditions for rice panicle was helpful to promote the expression of heterosis potential completely. Within the middle-late developmental periods (from the fifteenth day to the thirtieth days after flowering), additive effects played major role, and its genes expresed in the most active state. Genetic selection for panicle conducted in this period was expected to gain better genetic advancement.