Occurrence of Varietal Differences in Prorein, Phosphorus, and Potassium Content in Brown Rice, and Influence of Temperature and Shading during the Ripening Period on It

Abstract

1. Among the varieties, the earlier heading varieties made smaller yields and their percentages of protein, phosphorus, and potassium content in brown rice were higher. 2. Among the varieties, there was high positive correlation between percentages of protein, phosphorus, and potassium content in brown rice and the temperature during ripening period. 3. Varietal differences in the percentage of these in brown rice observed under the same temperature during the ripening period, Low (day: 21°C, night: 19°C) and High (day: 29°C, night: 26°C). The percentage of these in brown ricc was higher in earlier heading varieties not only under low temperature but also under high temperature. 4. Percentages of protein, phosphorus, and potassium content in brown rice were higher in the mutant than in the original varicty Koganemochi. 5. By shading treatment during the ripening period, the percentage of protein, phosphorus, and potassium in brown rice became higher. The rate of the increase was larger in protein than in phosphorus and potassium content.