Anther culture application to breeding of a restorer for a male-sterile cytoplasm of wild rice (ms-CW).

Abstract

Breeding of a restorer line for the male-sterile cytoplasm [ms-CW] of wild rice (W 1 ; Oryza rufipogon Griff.), identified by KATSUO and MIZUSHIMA (1958), was demon-strated by transferring the restoring gene(s) of W 1 to a cultivar through anther culture. Anthers of the F1 hybrid between W I (=) and O. sativa L. cv. Somewake (=) were cultured and two regenerated plants with high pollen stainability were obtained. Of these two plants, one was sterile in seed set, but the other (A1) was fertile and its selfed progenies (A2) also showed a high seed fertility. In a test cross of one of A 2 plants (=) with a cytoplasmic male-sterile strain carrying the cytoplasm of W1 and the nucleus of cv. Reimei, the resulting F1 gave a high seed fertility, demonstrating that the regenerated plant (A1) possessed restorer gene(s). The F2 and BIFI progenies of W1 (=)/Somewake in the conventional crossing showed a wide variation in pollen stainability and seed fertility, that might be due to not only cytoplasmic but also genic hybrid sterility. These results suggest that anther culture is effectively utilized for breeding restorer lines from remote hybrids, especially when they suffer from hybrid sterility.