Abstract
As reported in the previous paper, it was possible to express the leaf color by means of standard color plate, which was made of commercial embroidery thread. Furthermore, the authors tried to clarify the relation between the leaf color and the nitrogen content in leaf blades, in the case of different varieties grown in Konosu, and of the identical variety grown in different regions. Manryo and other varieties were used, and the former variety was grown at each prefectural agricultural experiment station of Aomori, Miyagi, Shiga and at three agricultural experiment stations in Korea, in accordance with each planting practices. On the basis of measurement values of the leaf color at the nearly identical growth stage of rice plants, correlation and regression coefficients between the leaf color and the nitrogen content in upper 3 leaves were determined. Results obtained were summarized as follows: 1. Even in case of the variety grown under different cultural conditions at a given region, the fact reported in the previous paper was confirmed again. 2. In different varieties grown at Konosu, a high correlation between the leaf color and the nitrogen content in leaf blades was also found. 3. The leaf color and the nitrogen content in leaf blades of the identical variety, Manryo, which was grown at different regions, showed a high correlation in each region, where the observation was conducted, so long as the growth stage was in the range of 19-50 in the number of days before heading. 4. If the growth stage of rice plants was nearly identical, the fact mentioned above was also established even though the rice plants were grown at different regions. 5. In the regression coefficient between the leaf color and the nitrogen content in leaf blades in each observation, no significant differences among leaf positions were found, but the regression coeffiicient became larger as the growth stage of rice plants advanced.
