| Oilseed rape is the first major source of domestic edible vegetable oil,and improving its production and quality is vital to ensuring the security of China’s oil supply.Anhui currently grows 7 million acres of oilseed rape,and as the expansion of oilseed rape in winter fields continues to advance,the recovery of oilseed rape production continues to accelerate.However,the stubble contradiction,the lack of late-sown high-yielding oilseed rape varieties,and the relative lag of late-sown high-yielding cultivation techniques have made it difficult to effectively exploit the yield potential of expanded oilseed rape in winter idle fields.The purpose of this comprehensive study is to offer a theoretical and empirical foundation for the growth of oilseed rape in winter fields.The main research results are as follows:1.24 widely promoted oilseed rape varieties were collected from various provinces in the Yangtze River basin,and a two-year yield identification trial was conducted in Dongzhi County,Anhui Province,to systematically analyze fertility,yield,plant type,and other related traits,and three high-yielding oilseed rape varieties with suitable fertility were screened,namely Fengyou 737,Huiyou 50 and Ning R101,whose yield per unit area was 1040.74 kg/hm~2on average,significantly higher than the average of 717.13 kg of other participating varieties The average yield per unit area was 1040.74 kg/hm~2,which was significantly higher than the average level of 717.13 kg/hm~2of other varieties.2.The biological foundation of yield reduction under late sowing conditions in oilseed rape was elucidated by systematically examining the individual growth and development patterns,yield components,and three high-yielding varieties and a novel early-maturing kale variety(Sunshine 131)under late sowing conditions.It was found that delayed sowing significantly shortened the fertility of the varieties by 10-20 days,reduced the total number of leaves on the main stems,reduced the effective temperature and light energy utilization,resulting in a 3.02%-18.97%reduction in plant height,40.02%-79.79%reduction in biomass,and a significant reduction in the number of corms,thousand-grain weight and oil content of the whole plant,which ultimately led to a reduction in yield per plant.3.Comparing the characteristics of different densities of rape populations under normal and late sowing conditions,it was found that increasing density could compensate to a certain extent for the effects of late sowing on individual rape development and increase the resource utilization of the population.Increasing the density could significantly increase the population biomass and angular fruit number per unit area,and eventually increase the yield per unit area by 18.12%-17.08%.Among them,Ning R101 has the greatest potential to increase the yield under late sowing conditions at dense planting,with a population of 600,000 plants/hm~2increasing yield by 72.18%compared to a population of 375,000 plants/hm~2.4.The combined effect of sowing date and density configuration on yield can be found to be that the density of Fengyou 737 is more suitable around 600,000 plants/hm~2when sown around October 10,while the sowing densities of Huiyou 50,Ning R101,and Sunshine 131 are more suitable around 525,000 plants/hm~2;and the density of each variety should be further increased under late sowing conditions to compensate for the negative effect of insufficient individual growth on yield.Under late sowing conditions,the density of each variety should be further increased to offset the detrimental impact of insufficient individual growth on production. |
