Studies on the Soft-Textured Rice Kernel : VII. The soft-and the hard-textured rice kernels in the process of forming and the amount of fertilizer

[摘要] The present paper deals with the relationship between both the soft-and the hard-textured rice kernels in the process of forming and the amount of fertilizer given to them, as indicated in Report III of our study. In any of the 4 years from 1955 to 1958 and in any testing plot, the graphs for Protein-N/ Crude-starch % (abbreviated (P) below) and (Total sugar+Soluble-N)% (abberviated (T) below) in the process of growing into the rice kernel described the equations of the exponential function type b/k y=ae (x is the number of days after flowering, y is the value of (P) or (T) corresponding to x) and the values of a and b were shown to be decided by such factors as variety, producing place, year and the amount of fertilizer. In addition, for any variety of husked rice produced in Fukui, if it is cultivated by the standard method (standard, heavy, no fertilizer) (P) became less than 1.45% and (T) gradually reduced as ripening went on, but all through the ripening period it was always above 0.65%. This result was very characteristic of the soft-textured rice kernels. On the other hand, as to the husked rice produced in Osaka (P) was above 1.45% through the whole period and (T) became less than 0.65% near the end of ripening period, which was characteristic of the hard-textured rice kernels. Within this range, there were varying differences between Norin No. 1, Yutakasenbon, Norin glutinous No. 5. Next, as to the influence of the amount of fertilizer, the plot given heavy fertilizer (50% more than standard), as compared with the standard plot, decreased in 1, 000 grain dry weight, crude starch %, and total sugar %, and increased in total-N %, soluble-N % and protein-N%. The ranges of increase and decrease in Fukui are larger than those in Osaka, but the influence of heavy fertilization was plain as the result of this test we have learned that (P) increased less than 0.201% and (T) decreased less than 0.21%. On the other hand, the plot with no fertilizer showed just the reverse results to those for the plot with heavy fertilizer, and we found that the influence of using no fertiltzer was greater in Fukui than in Osaka. At any rate the influence of no fertilization was very plain. Generally speaking, the same tendency could be seen as to Vitamin B1. In any plot, however, fertilization heavy or no was of little influence that the soft-textured rice kernel did not turn to the hard-textured and we saw none of the reverse result. We also found out (P) and (T) were larger subject to the duration of sunshine and the air temperature.

[学科分类] 农业科学（综合）