抄録
1. A fluctuation curve of Japanese rice varietes was made for the numbers of stems per plant, using the data of variety tests in Prefectural Agricultural Experiment Stations during 1931∼1940. In this curve, the mode is 14.0, the mean is 14.93, σ is 3.81, and the skewness is 24.70%. 2. The fluctuation curve for the number of stems per plant drawn from the data of the each many prefectures shows + skewness. The center of gravity of distribution inclines to the left. The tendency is shown for the year's fluctuation curve also. 3. The number of stems per plant in every prefecture may depend on the tendency of the Prefectural Agr. Exp. Stat. in which whether the "number of ear" type or the "weight of ear" type of rice varieties are mainly cultivated. It also depends upon the number of plant per Tsubo as well as the yielding efficiency of the soil. 4. Many leading paddy rice varieties of the whole country were classified by the mean number of stems per plant, using the "absolute number method". The "mean deviation value" of the number of stems per plant was also culculated. The correlation coefficient of the "absolute numbers" with the "mean deviation numbers" are + 0.850. 5. In paddy rice varieties, the following relation may possibly be established. The theoretical number of stems per plant of a given variety at a given locality is equal to: (1). The mean number of stems per plant of the locality + "The mean deviation value" of the variety. (2). The mean "absolute number" of the variety + local deviation value. The theoretical number of stems per plant of a given variety at a given locality in a definite year may equal to: The theoretical number of stems per plant of the variety of the locality × the regression coefficient of the climate of the year. 6. The relations stated above were illustrated by a glaph. 7. The author argued an idea of the possibility of investigating on the rice characters, such as yield, stem length and number of stems, by the simultaneous equation. Characters = function (rice itself × climate × soil efficiency × cultivation). Using many such formulae we may investigate theoreticaly the characters of rice.
