Studies on the Seed Production of Soybean : VII. The ability of photosynthesis in F1 and F2 generations

[摘要] It is important for the improvment of the ability of photosynthesis of soybean plants to clarify the genetic mechanism controlling photosynthesis of the plants. The authors determined the ability of photosynthesis of F1 and F2 generations in 1967 and in 1968. The results are as follows: 1. In the analysis of variance of the net photosynthetic rate, significant differences were observed among the data of each surveying date. Then the photosynthetic rat was represented as a relative value against the average rate of photosynthesis surveyed every day, instead of using the absolute value. The ability of photosynthesis of F1 of Norin-1×Harosoy was lower than that of Harosoy, but showed no significant difference from that of Norin-1. The photosynthetic rat of F1 of the reciprocal cross between Harosoy and Manshu was also lower than that of Harosoy, but showed no significant difference from that of Manshu in the most cases. Therefore, the low ability of photosynthesis of Norin-1 and Manshu was noticed as a dominant character. 2. The rates of photosynthesis of F2 generations of Norin-1×Harosoy, Manshu×Harosoy and Miyagi-shirome×Hakuho (6) indicated the normal distribution without any exceptions. It suggests that the genetic mechanism controlling the ability of photosynthesis is quantitative. 3. Regarding the relationship between the photosynthetic rate of F2 and the total N content per unit area of leaf, the following relationship was ovserved, i. e., the individuals of high and low photosynthetic ability were observed among the individuals with high N content, but there were few individuals of high ability of photosynthesis among the individuals with low N content. The same relationship in the cace of total N content was also observed among the thickness of a leaf, the leaf fresh weight per unit leaf area and the rate of photosynthesis. But these were observed only in the cases of leaves of middle and lower positions. No relationship was observed with the growth habit, flower color, ped's pubescence color and the leaf shape (ratio between the length and width), and in most cases, no relationship with the leaf dry matter weight per unit leaf area was observed. There was a progeny in which any certain relationship was not observed between the number of days for plant growth and the ability of photosynthesis, or there was a progeny in which few individuals of high ability of photosynthesis were found in the late-maturing plants. 4. From the results, the fellowing possibilities were discussed: (1) the possibility to improve the photosynthetic ability of the variety with low ability, and (2) the possibility that introduce the high ability of photosynthesis of the blant of indeterminate growth habit to the plant of determinate growth habit by retaining the growth habit itself.

[学科分类] 农业科学（综合）