Abstract: Cultivars of japonica rice (Oryza sativa) with small panicle angle have high yield and poor quality. Grain traits are associated with both yield and quality. To offer useful information for breeding cultivars with both high yield and good quality, we investigated the correlation between panicle angle and seven grain traits of Bing 8979 (erect panicle; P1), C Bao (curved panicle;
P2) and 349 recombinant inbred lines derived from the cross P1×P2. Coefficients of linear correlation between panicle angle and the seven grain traits were calculated, and genetic patterns were analyzed by mixed major-gene plus polygene inheritance models. No significant linear correlation was found between panicle angle (PA) and grain thickness (GT), PA and grain length/GT (GL/GT), and PA and grain width/GT (GW/GT). A significant linear correlation was found between PA and 1 000-grain weight (1000GW), PA and
GL, PA and GW, and PA and GL/GW (P < 0.01). Genetic analysis revealed that the seven grain traits were controlled by two major genes plus polygenes. Interactions of the two major genes varied with the traits. The traits 1000GW, GL, GL/GT and GW/GT were mainly controlled by the two major genes, and GW, GT and GL/GW were mainly governed by polygenes.

Key words: correlation, genetic analysis, grain traits, japonica rice, panicle angle