Analysis on the Main Factors Influencing Grain Yield Level of Machine-transplanted Rice Wuyujing 3

[Objective] The aim was to discuss the main factors influencing grain yield level of machine-transplanted riace Wuyujing 3.[Method] A field study was conducted to investigate the effects of transplanting time,transplating density,seeding raising method and nitrogen application on the grain yield and yield components and to analyze the mian factor influencing the grain yield under different grain yield level.[Result] The earlier the transplanting time,the more panicle numbers per unit area,spikelets numbers per panicle and spikelets number per unit area,the grain yield was easier to obtain.The treatment of basic seedlings 1 200 000-1 500 000 hm2 showed higher the panicle numbers per unit area,spikelets number per panicle,spikelets number per unit area and grain yield than other treatments.The grain yield per unit area at nitrogen 300 kg/hm2 was higher than that at nitrogen 270 kg/hm2 and 300 kg/hm2.At the nitrogen level of 300 kg/hm2 and 330 kg/hm2,the treatment of the ratio of base fertilizer to top dressing at 7∶ 3 had higher grain yield than that at the 6∶ 4,and the opposite conclusion was drawn at the nitrogen level of 270 kg/hm2.The treatment of the ratio of base fertilizer to top dressing at 7:3 at nitrogen 300 kg/hm2 level showed the highest grain yield among six nitrogen treatments.In the high-yield research,little difference in the panicle numbers per unit area and significant differences in spikelets number per panicle,filled grain per panicle,and spikelets per unit area were obtained among fields with different grain yield.The F type with highest grain yield showed higher spilelts number per panicle,filled grain percentage,filled grains per panicle,the spikelets per unit area than other types.At the average grain yield less than 9 000 kg/hm2,the panicle numbers per unit area,spilelets number per panicle and filled grain percentage all had significant effects on grain yield per unit area.The effect of the former on the grain yield was significantly greater than the later two on the grain yield.At the grain yield about 9 000-10 500 kg/hm2,the panicle numbers per unit area showed more important influence on grain yield than other factors.At the average grain yield more than 10 500 kg/hm2,the grain yield per unit area was significantly affected by the panicle numbers per unit area,spilelets number per panicle and filled grain percentage,especially by the spikelets number per panicle.The hills,panicle numbers per hill were strongly correlated with the panicle numbers.When the output was lower than 9 000 kg/hm2,the former imposed larger influence on panicle numbers than the latter one;when the output was larger than 9 000 kg/hm2,the latter had larger influences on the effect of panicle numbers.