Evaluation of Barley Male-Sterile Cytoplasm Based on Fertility Restoration and the Effect of the Cytoplasm on Malting Quality in Japan

The msm 1 and msm 2 cytoplasms cause male sterility in barley. In order to clarify whether these cytoplasms can be used for hybrid seed production in Japan, we investigated the fertility restoration under environmental conditions in Japan using alloplasmic lines and an isogenic line. Fertility of barley lines containing msm1 and msm2 was completely restored by the restorer gene Rfm 1a. The effect of cytoplasm on malting quality was also investigated, but no significant difference in malting quality was observed between lines possessing msm1, msm2, and original cytoplasms. Malting quality also did not differ between Rfm1a/Rfm1a and Rfm1a/rfm1a genotypes, suggesting that Rfm1a and its flanking genes are not associated with heterosis for malting quality. Possibilities of hybrid barley breeding using these male sterile cytoplasms are discussed.