雄性不稔을 利用한 水稻 雜種品種 開發 Ⅵ. japonica型 水稻에서 細胞質的-遺傳子的 雄性不稔 및 稔性回復系統 育成

Development of hybrid rice facilitated by cytoplasmic-genetic male sterility Ⅵ. Breeding of CGMS and restorer lines in japonica rice

This study was conducted to develop the Japonica hybrid rice. Twelve CGMS lines were bred by backcrossing the corresponding maintainers to COA-ms, the CGMS stock obtained from the introduced Japonica hybrid seed. The CGMS lines showed significantly late heading date and shorter culm length compared with the maintainer, varying more or less with years and lines. Male-sterile cytoplasm of COA-ms was proved to be different from that of WA, TN1, Gam, Di, and 0. spontanea type. None of 337 Japonica rice cultivars tested showed complete fertility restoration in seed setting when crossed to COA-ms, and 261 cultivars out of them were found as complete maintainers. In F₁ nursery, two F₁ plants which showed complete fertility-restoration for COA-ms were found in a cross, COA-ms/Fukuhikari, and three lines having restorer gene were selected in their F₄ progenies. GP15-6, one of them, was crossed to eight Japonica cultivars, and 138 homo-restorer lines were developed via anther culture of the F₁’s, consequently. Developed CGMS-restoration system was found to be gametophytic.