Induction of photoperiod sensitive genetic male steriles for use in hybrid rice seed production

Summary

The most notable photoperiod sensitive genetic male sterile in rice is the Nongken 58S line in China. Two sources of environmentally sensitive genetic male sterile mutants were found in California. The photoperiod-sensitive genetic male steriles (PGMS) have the potential for reducing hybrid rice breeding from the present 3-line system to a 2-line system. The long-range objectives of the present project were to induce an array of genetic male steriles in rice, and then to evaluate these at different day lengths in order to find steriles that become fertile in selected environments. Three genetic male steriles were selected from gamma irradiation of southern US cultivars. Inheritance of these mutants was studied through progeny tests in M₅ to M₇ generations and through fertility characterization of pollen and spikelets. Seed set on steriles under open pollination ranged from a low of 8.1% for Cypress 1819 to a high of 32.9% for Kaybonnet 1789.