Abstract: A genetic model for triploid endosperm including endosperm effect, cytoplasmic effect, and maternal effect was used to analyze the amylose content (AC) of F2, F3 seeds and their parents derived from 5×5 incomplete diallel cross of japonica three lines rice, in different years, panicle positions, and two environments. The results showed that in the two environments, AC was controlled by genotype, with predominant endosperm additive effects. With panicle position as environmental factor, significant cytoplasmic variance (V_C) could be detected; for the interaction effect variances, direct dominant × environment variance (V_DE) was primary and cytoplasmic × environment variance (V_CE) was secondary. According to the genetic prediction of interaction effects, V_CE was the biggest for different panicle positions in most cultivars, and cytoplasmic × environment effect caused AC decrease in the grains of middle and upper panicle positions and increase in grains of lower panicle position in CMS lines which had opposite performances to restorer lines. With year as environment factor, V_C was not significant; maternal dominant × environment variance (V_Dm) was the main component of interaction variance.

Key words: Japonica hybrid rice, Amylose content(A_C), Environment, Panicle positions, Genetic analysis