On the yielding efficiency of Japanese rice varieties : continued : On the heading period of rice varieties continued

[摘要] This report relates on the heading periods of rice varieties all over Japan proper. Every year from 1931-1940, all heading periods of rice varieties in variety tests in all perfectual agricultural experiment stations all over Japan proper are sumed up in a table, and from that the yearly fluctuations curves of heading period of rice varieties all over Japan proper are made. The numbers of rice varieties summed up in this calculation are about 4000 varieties every year The most early day of heading is July 19th. and the latest day of heading is September 25th. and the curves displays a monomodal asymmetric curves. The mode of the distribution curve of heading period is exceptionally early in 1931 and 1934, the bad year. And in the normal year the mode is at 7th-10th of September, and it coincide with the critical day for rice crop the 1st of September and the 10th of September. The mean of distribution is about 27th-3lst, Augast. And it alters about 3-4 days by the year. And it is early in the good year, and it is late in the bad year. The skewness of the curve is all negative except 1936, that is, the center of distribution is located to the right side of the curves. The heading period of Japanese rice plant is from 19th of July to 25th of September, and in normal years it is from 25th of July to 20th of September. From the point of view of all over Japan proper the late and early of heading period has negative correlation with the yield and stem length, and has positive correlation with the number of stems. As the reasons of early and late of heading period of rice the mean temperature from March to November, and the mean temperature of July, and the hours of sunshine has a negative correlations, and the volume of rain fall has a positive correlation. I am willing to continue this investigation now on. The numbers of rice varieties summed up in this calculation are about 4000 varieties every year The most early day of heading is July 19th. and the latest day of heading is September 25th. and the curves displays a monomodal asymmetric curves. The mode of the distribution curve of heading period is exceptionally early in 1931 and 1934, the bad year. And in the normal year the mode is at 7th-10th of September, and it coincide with the critical day for rice crop-the 1st of September and the 10th of September. The mean of distribution is about 27th-3lst, Augast. And it alters about 3-4 days by the year. And it is early in the good year, and it is late in the bad year. The skewness of the curve is all negative except 1936, that is, the center of distribution is located to the right side of the curves. The heading period of Japanese rice plant is from 19th of July to 25th of September, and in normal years it is from 25th of July to 20th of September. From the point of view of all over Japan proper the late and early of heading period has negative correlation with the yield and stem length, and has positive correlation with the number of stems. As the reasons of early and late of heading period of rice the mean temperature from March to November, and the mean temperature of July, and the hours of sunshine has a negative correlations, and the volume of rain fall has a positive correlation. I am willing to continue this investigation now on.

[学科分类] 农业科学（综合）