Breeding Theory and Practice of "Shanyou 63",the Variety with the Largest Cultivated Area in China

The cultivated area of "shanyou 63" has been kept the first in China since 1986. The average cultivated area was 4. 67 million hm2 per year, accounted for 22% of the total area of indica zone in China and more than 6.67 million hm2 in 1990.It is almost cultivated all over the indica cultivated zone from17°36’N to 37°49’N and from 100°36’E to 121°56’N. It has been cultivated 5267 million hm2 and in-creased about 58.5 billion kg grain from the year 1986 to 1 995. According to the national regional yield trial, it increased 1112 kg grain per hm2 comparcd with CK. General grain yield was 7500 kg to 9000 kg and the highest was 13. 9 kg per hm2. It has good ratoon ability and the grain yield ol ratconing rice reached 8231 kg per hm2. In this article,the author also introduce the breeding course,yield constitu-tim,photosynthesis characteristics, resistant ability and gain quality of Shanyou 63 and sunmarize the successful breeding pratice of Shanyou 63.