SEED PRODUCTION ABILITY OF MALE-STERILE L INES OF COMMON WHEAT INDUCED BY THE INTERACTION BETWEEN AN S-V TYPE CYTOPLASM AND A 1BL-1RS CHROMOSOME

Development of hybrid wheat has been unsuccessful despite over 30 year s of research in which G type cytoplasm of Triticum timopheevi was use d as the source of male-sterility. Alternatively, S-v type cytoplasm o f Aegilops kotschyi was proposed to be a promising candidate as the ma le-sterility source for hybrid wheat breeding. Nonaka et al. (1993) de veloped male-sterile lines of 13 cultivars of common wheat (Triticum a estivum) by a breeding scheme which utilized the interaction between a n S' type cytoplasm and a 1 BL-1 RS chromosome proposed by Toriyama et al. (1993). We herein report the F-1 seed production ability of these male-sterility lines. Sixteen plants of each male-sterile line were p lanted in 3 rows with one row of pollen parents. Then they were covere d with a nonwoven fabric during flowering period to isolate from other pollen sources. Table 1 and 2 indicate F-1 seed production ability of these male-sterile lines. Some varietal differences were found in spi kelet fertility and hapliod plant induction. Male-sterile lines which were derived from Aobakomugi, Asakazekomugi, Fukuhokomugi and Norin 26 showed high ability of F-1 seed production. However, male-sterile lin es which were derived from Nishikazekomugi and Shiranekomugi showed lo w spikelet fertility and high frequency of haploid plant induction. Ex cept for these 2 male-sterile lines, grain number per spike of most ma le-sterile lines were between 20 and 30. This is more than half of tha t of common wheat cultivars with normal cytoplasm. The F-1 seed produc tion ability of these male-sterile lines is assumed to be satisfactory for their practical use.