Abstract: Nutritional and taste quality are focused in rice (Oryza sativa L.) breeding for grain quality. Panicle type may have certain effect on grain quality traits. However, research in detail on grain quality difference between/within erect and curved panicle rice is not well-documented. The objective of the present study was to characterize the difference in several nutritional and cooking qualities at different seed positions in japonica rice cultivars which differ in panicle type. Three erect and three curved panicle japonica rice cultivars of similar maturity were grown in randomized block design in 2006. After maturity protein content (PC), amylose content (AC), and taste quality (TQ) of milled rice were measured. The results showed that panicle type had considerable influence on PC, AC, and TQ at the different parts of panicle, for erect panicle cultivars, PC and AC increased with the grain position from the upper to the lower parts, while TQ showed reverse trend; for curved panicle ones, PC and AC showed no regular trend, but TQ was the same as that of erect panicle cultivars. In the same panicle, the PC of secondary branches was higher than that of primary branches, while AC and TQ behaved reversely. In the same rachis branches, the 2nd and 3rd grain of secondary branch at lower part had higher PC and lower TQ, the 1st to 6th grains of primary branch at mid and upper part had lower PC and higher TQ, no rule was found for AC at different grain positions of panicle. The difference of referred quality traits at different grain positions in erect panicle was higher than that in curved panicle, resulting from higher grain density in erect panicle. Results from this study will facilitate erect panicle cultivars in rice breeding for quality in Northeast China.

Key words: Japonica rice, Panicle type, Grain position, Protein content, Amylose content, Taste quality