Studies on the change of leading rice varieties in the temperate zone of Japan and comparison of some characters among them

Three leading varietis, Shinriki, Asahi and Norin No.18 which appeared in 1877, 1908, 1941, succesively, were reared under same cultural conditions at the Experimental Farm of the Kyushu Unversity in 1948.Comparison were made about such characters as culm length, ear lengh, number of ears per plant, total plant weight, total ear weight per plant and 1000 unhulled grain weight from the biometrical view point(table 1 and 2)and discussion was intended to forcuss the direction of imrovement of those characters above mentioned for the rice variety in the warm zone in westsouthen part of Japan.