Studies on the response of heading for day-length and temperature in rice plants. : II.Response of upland rice and foreign rice and the relation their geographical distribution.

Abstract

188 varieties of foreign rice plants and 25 varieties of Japanese upland rice were examined during 3 years from 1940 to 1942 on their response of heading time for day-length and temperature. Most of upland rice seemed to be low sensitive for day-length and temperature. Foreign rice, however, showed wide variability for the degree of basic vegetative growth and sensitibity for daylength and temperature, and it seemed to be closely connected with their geographical distribution. These results tell us that the cultivated riceplants in every region in the world have been selected by the day-length, temperature and agronomical technics in their locatiori during a long: historical time.