Researches on Suitable Planting Date and Sowing Rate for the Late-sown High Yield of Different Winter Wheat Cultivars in Guanzhong Area of Shaanxi

A field trail using split-plot design with three winter wheat varieties,four planting dates and four kinds of sowing rate was conducted to study the effect of different planting date and sowing rate on colony properties and grain yield of wheat and the suitable planting date and sowing rate for the different winter wheat varieties under the late-sown condition.The result showed that the total stems and spikes of colony in each variety dropped as sowing date postponed and the sowing density reduced;and the optimized planting date and sowing rate for high yield were various among different varieties.Grain yield of Xinong 979 could reach up to 9 200 kg per hectare,correspondingly,the suitable planting date was 15th Oct.and sowing rate was 4 500 thousand seedlings per hectare.For Xiaoyan 22,the highest grain yield was 8 290 kg per hectare under planting date on 19th Oct.and sowing rate 2 250 thousand seedlings per hectare.But for Shaan 558,the late-sown date was until the end of October(27th Oct.),and sowing rate was 3 750 thousand seedlings per hectare,its highest grain yield was 8 160 kg per hectare.Therefore,we can conclude that the suitable structure of colony can be reached for different winter wheat varieties under optimizing planting date through adjustment and control of sowing rate,and also realized the high yield of the wheat.These results can be applied to optimize cultivate plan for the late-sown high-yield winter wheat in Guanzhong area of Shaanxi province.