关键词: 直播, 杂交稻, 播种量, 光能利用效率, 产量

Abstract: In order to understand the effects of seeding rate and maturity stage on grain yield and radiation use efficiency （RUE） of direct seeding rice in wheat-rice cropping system, a field experiment with early maturity rice cultivar Chuanzuoyou 8727, medium maturity rice cultivar Fuyou 838 and late maturity rice cultivar Nei 6 you107 was conducted at Chengdu Plain in 2019. The seeding rate treatments were established as 15.0, 22.5, 30.0, 37.5, 45.0 kg/hm2 by artificial broadcasting. The results showed that panicles per m2 and total dry matter weight of direct seeding rice showed an increasing tendency with seeding rate increasing, while spikelets per panicle and dry matter weight per plant of direct seeding rice showed a decreasing trend with seeding rate increasing. The grain yield and RUE of direct seeding rice firstly increased and then decreased with seeding rate increasing. Chuanzuoyou 8727 recorded the highest grain yield and RUE when the seeding rate was 30.0 kg/hm2, and Fuyou 838 and Nei 6 you 107 recorded the highest grain yield and RUE when the seeding rate was 22.5 kg/hm2. Chuanzuoyou 8727 produced higher grain yield than Fuyou 838 and Nei 6 you 107 by 8.8% and 3.7%, respectively. The higher panicles per m2, seed setting rate and harvest index in Chuanzuoyou 8727 were responsible for high grain yield compared with Fuyou 838 and Nei 6 you 107. Chuanzuoyou 8727 had higher RUE than Fuyou 838 and Nei 6 you 107 by 15.3% and 13.3%, respectively. The results suggested that the optimum seeding rate of hybrid rice with early maturity is 30.0 kg/hm2 under wheat-rice cropping system in Chengdu Plain.

Key words: direct seeding, hybrid rice, seeding rate, radiation use efficiency, grain yield