雄性不稔性을 利用한 水稻 雜種品種 開發 Ⅹ. 細胞質的 雄性不稔系統×稔性回復親과 不稔維持親×稔性回復親 組合間의 生産性 比較

Development of hybrid rice facilitated by cytoplasmic-genetic male sterility Ⅹ. Performance relationship between CGMS×restorer and CGMS maintainer×restorer

In the breeding of successful hybrid variety of rice, a typical self-pollinated crop, the proper system of male sterility and the desirable fertility restorer with high combining ability are essential. The main objective of this experiment was to secure the possibility of pre-selection for combining ability of newly developing CGMS×restorer crosses with combining ability CGMS maintainer×restorer crosses. Both newly developed CGMS and their maintainers were crossed with 7 Korean cultivars known as Tongil-type restorer and examined their combining ability relationship between maintainer×restorer and CGMS×restorer crosses for grain yield and its associated characters. In the crosses of CGMS maintainer×restorer, the higher relative combining ability was found in two CGMS maintainers, wx498 and wx817, with mean grain yield of 868.1 and 859.2kg/10a, and in three restorers, Milyang57, Milyang56 and Suweon294, with mean grain yield of 925.6, 827.0 and 828.6kg/10a, respectively. The standard heterosis in the cross of CGMS maintainer×restorer ranged from 83.3 to 129.0% with the highest in the cross of wx498×Milyang57 which yielded 1039.7kg/10a. The hybrids of CGMS line×restorer cross which showed higher values of the relative combining ability, showed also the greater combining ability in the crosses of maintainer×restorer with highly significant correlations coefficients in grain yield and its associated characters between two groups of crosses. This may suggest that the results of maintainer×restorer crosses can be utilized in the selection of recurrent parents for the breeding of male sterile lines. Highly significant positive correlations were found between grain yield and both the grain number/panicle and the percentage of filled grains, respectively.