Abstract: Five newly developed PTGMS Lines, i.e., Fulong S2, Fulong S3, Fulong S8, Fulong S9, Fulong S12 and Pei'ai 64S (CK), as female parents and 6 newly developed restorer lines, including Longhui 611, Longhui 1031, Longhui 3381, Longhui 36, Longhui 128 and Longhui 339, as male parents were used to generate 36 combinations of new rice varieties based on a NCII mating design. The combining abilities and trait inheritabilities on the growth, plant height and yield related characteristics of the resulting hybrids were examined. Both additive and non-additive allelic parental gene effects were evident, with the additive effects being greater than the non-additive effects. The high narrow inheritabilities on the traits, such as plant height, number of panicles per plant and number of grains per panicle, suggested that they could be selected at early generations for the breeding. There was a very significant correlation between the total general combining ability (GCA) (correlation coefficient=0.85) or specific combining ability (SCA) effect (correlation coefficient=0.52) of the parents and the grain weight per panicle of the combinations. However, there was no correlation between the total GCA and SCA effects from the parents. Fulong S3 and Fulong S8 were the best among all PTGMS lines. The GCA effect of Fulong S2 was moderate on yield, with the highest SCA variance. It appeared that an ideal combinations could be obtained through extended mating test and screening using Fulong S2 to improve the 1000-grain weight on the other varieties. The GCA of Fulong S9 were the best in regard to the time required from sowing to heading, panicle length, and number of filled grain per panicle. Fulong S12 could be used to lower the plant height. Longhui 1031 and Longhui 3381 were the best among all restorer lines with overall excellent performance. The GCA of Longhui 611 was desirable in so far as the time required from sowing to heading, plant height, and number of grains per panicle are concerned. The GCA of Longhui 36 showed good panicle length and number of grains per panicle.Longhui 339 had a high 1 000-grain weight.

Key words: indica rice, two-line hybrid rice, agronomic characteristics, combining ability, inheritability