Some characters of indigenous ricc varietics in Japan.

Abstract

Indigenous varieties gathered from some isolated islands and mountainous parts of Japan, which are thought to be cultured from year to year since near 100 years ago or more, was cultivated and observed their morphological and ecological characters comparing with several improved varieties of Japanese paddy rice and some of upland and foreign rice. The shape of grains of indigenous varietics was almost the same with improved varicties which are the typical Japonica. However, the former have longer culms and spikes than the former. The length of culms, panicle and leaf, the weight of ear, number of rachis branches and tillers of indigenous show wide variations as foreign rice. The plant type of indigenous, as the result, resembles to them. Though the reaction of paddy to phenol and solubility of grains by KOH, which are used as the discriminant characters between the Japonica and Indica type of rice, some of indigenous varieties reveal positlve to phenol and negative to KOH as some of foreign rice. The photoperiodic response and sexual affinlty of thc indigenous rice also investigated on the phylogenic point of wiew. One of them has a large basic vegetative growth hablt and low sensitivity for The sexual afflnities of the short-day treatment. The sexual affinities oh them to 2 Indica varieties ( Surjamukhi and Charnack ) also variates in wide range. The indigenous varieties of Japan seems to have many genotypes in morhological and ecological characters as foreign rice and breeders in Japan improved them to the special genotypes having the short culm, many Spikes, awnless and short-narrow leaves.