BREEDING OF CANDIDATE LINES FOR MALE STERILITY-MAINTAINER BY ANTHER CULTURE FOR HYBRID WHEAT PRODUCTION USING AN S(V) TYPE CYTOPLASM AND A 1BL-1RS CHROMOSOME

We previously proposed a new breeding scheme to develop hybrid wheat u tilizing male sterility induced by the interaction between the S(v) ty pe cytoplasm of Ae. kotschyi and the 1BL-1RS chromosome (Toriyama et a l. 1991, 1993). In our proposed scheme male sterility-maintainer lines can be produced by two ways, i. e. the backcrossing method (Nonaka et al. 1993) and anther culture. This article reports the results of ant her culture. Donor for the 1BL-1RS chromosome, namely, the strain 911- B-8-10 (abbreviation, st. 911) was crossed to 13 Japanese wheat cultiv ars. The anther culture was conducted using the F1 and B1F1 plants. Fr equency of embryo formation in the F1s was higher than that in the par ental Japanese cultivars. The frequency observed in the B1F1s was lowe r than that in the F1s. High frequencies of embryo formation in st. 91 1 and the F1s were attributable in part to the 1BL-1RS chromosome. Sin ce the leaf rust resistance gene Lr 26 was located on the 1RS chromoso me arm, regenerated haploid seedlings were artificially inoculated by leaf rust (race 21B) to select resistant ones. Doubled haploids with r esistance were crossed with (S(v))-Chinese Spring having the 1B chromo some and with (S(v))-Salmon having the 1BL-1RS chromosome. The F1s of the former cross showed high selfed fertility, while the F1s of the la tter showed complete male sterility. This means that resistant doubled haploids obtained by anther culture can be used as a maintainer for d eveloping male-sterile line.