Effect Of Sowing Date And Planting Density On Yield,Quality And Agronomic Traits Of Shaanyou1203 And Shaanyou1209

Rapeseed as a kind of oil crops plays an important role in China,and improving the production of rapeseed is of great significance to ensure national food security and people’s living standard.With the development of large-scale and mechanized rapeseed production,it is necessary to popularize suitable mechanized varieties and research on corresponding high-yield cultivation techniques.In this study,shaanyou 1203 and Shaanyou 1209,newly registered varieties suitable for mechanization,were selected as experimental materials.According to their characteristics,it sets different sowing date and density gradient to study the effects of sowing date and density on the growth and development,lodging resistance,yield and grain quality of rapeseed,and to determine the suitable sowing date and density range of Shaanyou 1203 and Shaanyou 1209.The aim is to explore the high-yield cultivation technology of new varieties,tap their potential to increase yield,and realize the transformation of scientific and technological achievements.It provides theoretical reference for the large-scale cultivation of Shaanyou 1203 and Shaanyou 1209 in the appropriate range,and also lays a foundation for the popularization and application of rapeseed mechanized production.The main conclusions are as follows:1.Delaying sowing date or increasing density tended to shorten the growth period of rapeseed..With the delay of sowing date or the increase of density,plant height,the number of leaf of main stem,root and neck diameter and dry matter accumulation of per plant all decrease.The individual growth and development of early sowing was better than that of late sowing.2.Sowing date and density can affect lodging resistance of rapeseed.Delayed sowing date and increased density result in decreased tensile strength and breaking strength,and increased lodging index.In a word,lodging resistance of rapeseed decreased.The stronger lodging resistance of Shaanyou 1203 was less affected by sowing date and density than that of Shaanyou 1209.3.Sowing date and density can influence on economic characters and yield components of different varieties.With the delay of sowing date and the increase of density,the effective height of branch increased while the inflorescence length,effective primary branch number,effective branch number per plant,silique numbers on main inflorescence,silique numbers on branch and effective silique numbers per plant all decrease.With the delay of sowing date,the number of seeds per silique tends to increase.4.Sowing date and density have different effects on yield of different varieties.In a certain range,the effect of density on the yield of the two varieties increase first and then decreased.Increasing planting density can appropriately ensure the yield under the condition of late sowing.5.The quality of mature rapeseed grains is affected by sowing date.Under the condition of late sowing,the contents of oil and protein were higher,but the contents of glucosinolate were lower.And the change of density has no significant effect on the main quality indexes and main fatty acids.6.In the Huanghuai region,the sowing date of Shaanyou 1203 is from September 18 to25,and the density is 22000-25000 plants /667m~2,while the sowing date of Shaanyou 1209 is from September 13 to 20,and the density is 15000-18000 plants /667m~2.If sowing date is delayed to the end of September or early October,the planting density of Shaanyou 1203 and Shaanyou 1209 can increase to about 28000 or 21000 plants /667m~2 respectively.Then the dense planting can reduce the loss of yield of late sowing to a certain extent.