Genotype differences in dry matter accumulation and phosphorus absorption and use efficiency in rice

Twenty seven of middle-season and twenty nine of late rice cultivars were taken as testing materials, their genotypes were assigned into three groups of high, middle and low yields by least square and dynamic clustering method. The biomass and phosphorus absorption were investigated in different growth stages for various yield types using field experiment. There was extremely significant genotype differences in rice yield, phosphorus absorption and use efficiency among the rice cultivars in different growth stages. The maximum yields were 3.24 and 2.15 times higher than the minimum yields for data obtained from middle-season rice and late rice, respectively. The yield of late rice was 12.69% higher than middle-season rice, but the difference was no significant in phosphorus use efficiency between them. The largest phosphorus accumulation was in tillering-jointing stage for middle-season and high yield type, and in jointing-heading stage for late and high yield rice. There is not much dry matter accumulation in tillering-jointing stage, the largest accumulation was in jointing-heading stage for both the middle-season and late high yield rice. Dry matter and phosphorus accumulation during tillering-jointing stage played main role in yield of middle-season rice with the highest contribution rate to yield of up to 42.38% and 58.09%, respectively. The phosphorus accumulation during heading-maturing stage is important in yield of late rice with the highest contribution rate of up to 39.35%, and 16.16% of the dry weight was accumulated in this stage. In conclusion, the cumulative dry matter during tillering-heading stage and phosphorus absorption during tillering-jointing stage play key role in yield formation of middle-season rice, the cumulative dry matter in early stage and phosphorus in late stage are important to the yield of late rice