Effects of sowing date on growth and yield of different types japonica rice varieties.

Based on 21 tested materials which are representative japonica rice varieties with various maturities,taking the typical widely-adaptable indica hybrid rice variety Tianyouhuazhan as the control,the experiment was conducted to select varieties and investigate the optimum sowing date.The results showed that the varieties of Chunyou 58,Yongyou 8,Changyou 1,and Xiushui 63 had better growth period,stronger tillering ability and higher yield than the control under May 30th or June 19th seeding-time treatments.Thus,they were suitable to plant in Jinhua area.In all tested materials,it was found that Chunyou 58,which had the highest yield of 9.333 t/hm2,was most suitable for extension as single cropping rice or continuous double cropping late rice in Jinhua area.