Optimization of cultural factors affecting yield of hybrid rapeseed cultivar Yunyouza 10

To optimize cultural factors on double-low hybrid rapeseed(Brassica napus L.) Yunyouza 10,5 main factors including planting density(X1),pure nitrogen(X2),phosphate(phosphorus pentoxide,X3),potassium(burnt potash,X4),and boron fertilizer(available boron,X5) were studied using quadratic regression orthogonal rotational combining design.A mathematical regression model for yield was established Y=246.15+12.70X2+7.00X3-6.26X12-9.81X22-5.07X32-10.56X1X2-6.37X3X4,the order of significant affected factors was nitrogen,phosphate,planting density,boron,and potassium.Result showed that extremely high or low nitrogen,phosphate fertilizers and planting density decreased the yield of Yunyouza 10.Two types of interactions,between planting density and nitrogen,and between phosphate and potassium,had significant effects on yield.When the planting density was between 10.5 to 22.5(ten thousand plants per hectare),pure nitrogen was between 0 to 207kg per hectare,phosphorus pentoxide was between 0 to 96kg per hectare,and burnt potash was between 0 to 120kg per hectare,the interactions above were both positive.By method of frequency analysis,high yield of more than 3 900 kg per hectare could be achieved with the optimal condition including planting density between 15.48 to 17.94(ten thousand plants per hectare),pure nitrogen between 360.2 to 387.1kg per hectare,phosphorus pentoxide between 170.0 to 181.4 kg per hectare,burnt potash between 15.0 to 30.0kg per hectare and available boron between 1.46 to 1.84kg per hectare.