Analysis of Developmental Factors Determining Yield and Its Application to Yield Prediction and Culture Improvement of Lowland Rice : LX. Studies on the method for predicting the percentage of ripened grains and the weight of 1, OOO kernels by means of identifying the ripening grade in terms of "translucent proportion" in transverse sections of kernels.

Abstract

Using the previously reported method for expressing the ripening grades of a grain by "translucent proportion", exactly speaking the proportion of the width of a translucent area to that of the whole area in a transverse section of a kernel, the authors tried to find out how to express the ripening grades of a hill as well as a panicle, and how to recognize the time when the percentage of ripened grains and the weight of 1, 000 kernels can be predicted. As the result, it was clear that the ripening grade of a panicle and that of a hill can be satisfactonly expressed by the sum of the "translucent proportion", being classified into 0-6, of the first (terminal) grain and that of the second one on the primary rachis-branch located at the central portion of a panicle, and furthermore, the percentage of ripened grains as well as the weight of 1, 000 kernels can be predicted with accuracy at the time when the ripening grade of a hill attains about 11.5 in the sum of the values of "translucent proportion" of those two grains in an average panicle in the hill under any conditions differing in variety, circumstance and cultural way.