Fundamental studies on rice breeding through hybridization between Japanese and foreign varieties. III, Anomalous modes of segregation of glutinous character observed in hybrids between varieties of remote origin

Abstract

Summary Some anomalous modes of segregation in respect to giutinous character in pollens and in endosperms of seeds born on F1 hybrids between rice varieties of remote origin are described. Glutinous ×non-glutinous F1 hybrids from 72 different parental combinations among 25 varieties including 9 glutinous and 16 nonglutinlous ones were investigated. Eight of the 9 giutinous varieties used are of Japanese origin and one is of South American origin, all of these belonging to so-called Japonica group. Six of the 16 non-glutinous varieties belong also to Japonica, of which 5 are of Japanese origin and one, Sen-sho, is native to China, having been intoduced into Japan some 70 years ago. The other lO ones consist of 5 Indian, I Viet Namese, 1 Hawaiian and 3 Chinese varieties and they belong to so-called 1lrdica group (Table 1). In all of the F1's obtained among Japaneese varieties segregntion of glutinous character in both pollens and endosperms took place normally, i. e., the ratio non-giutinous vs. glutinous was 1 : 1 in pollens and 3 : 1 in endosperms. In some hybrids between Japanese and Indian varieties there occured a remarkable deviation from the normal ratio, presenting a significant decrease in the number of glutinous endosperm, though the segregation in their pollens was normal. In the two sets of hybrids in which other foreign varieties than Indian ones partook as a parent there was observed a significant decrease in the number of non-glutinous pollens. The segregntion ratio in endosperns was, however, normal in most of them. Sen-sho was found to behave in a complex manner.