RICE BREEDING FOR THE HYBRID COMBINATION OF SHANYOU 63 AND ITS RESTORER LINE MINGHUI 63

Years after cultivation, the hybrid combinations Shanyou No.2 and Siyou No.2 were gradually losing their resistance to blast because their restorer line IR24 was susceptible. In order to solve this probelm.a new restorer line Minghui 63 was produced by crossing IR 30 and Gui 630; Shanyou 63 by crossing restorer line Minghui 63 and ms line Zhenshan 97A. Reasults showed that this combination was marked by higher yield, better grain quality, more resistance to blast and extensive adaptability.It had extended rapidly, ranking first on the list in the planting area. In 1986 it covered 2. 26 million hectares in the south of China. Between 1982 and 1985, it usually took the lead in area whether in the country or in local districts; the average yield from 1982-1985 was 7.2T/ ha, increasing by 1.02T/ha or 16.1% as compared with the check combinations Shanyou No.2 and Shanyou No.6. It is estimated that the total yield increased by 1986 amounted 2.89 million tons. This combination was especially fit to grow as a medium variety because its growth period lasts 4-5 days longer than that of Shanyou No.2. If it is used as a late variety in the double cropping system, the sowing date should be taken into considerations in order to avoid the autumn cool. It is estimated that this combination will exten its planting area in the south of China and develop its social efficiency. And the other new combinations with the restorer line Minghui 63 are being experimented with and are under development.