Basic Studies on Hybrid Wheat Breeding VI.Production of Male Sterile Lines of Common Wheat Cultivars

Abstract

The male sterile T. timopheevi cytoplasm was introduced by successive backcrosses intcp 20 Japanese and 13 American cultivars of common wheat. In advanced backcross generations, all but four cultivars turned out to be complete or nearly complete male-steriles. Junrei-Komugi, and Norin 50, 52 and 69 were found to be carriers of a weak fertility restoring gene(s). From an investigation of their pedigrees, Junrei-Komugi, and Norin 50 and 52 were assumed to have received their gene(s) from their common ancestor, Shinchunaga, while Norin 69 appeared to have a different gene(s). Most male sterile lines of the other cultivars expressed male sterility constantly in different years (1969-1975), and in different localities (six locations from Kyushu ta Hokkaido in Japan). However, a few lines recovered selfed seed fertilities higher than 20% in Fukuyama in Chugoku District, where the environment seems to be shallow sterile for these lines. The out-crossing ability of all these male sterile lines was tested, using their seed setting rates under open-pollination. Male sterile lines of Aoba-Komugi, Bledsoe, and Lemhi 53 are considered to be good cross-fertilizers, while Karnvor, White Federation, Kokeshi-Komugi, Idaed 59, Fujimi- and Mikuni-Komugi are thought to be poor cross-fertilizers, the remainder being intermediate. With proper arrangement of pollinator rows, the male sterile lines tested showed a 51-83 seed-set by out-cross, which seems to be sufficient to guarantee hybrid seed production in Japan.