The Study On The Effect Of Rapeseed Yield,Quality And Production Potential Under Different Sowing Date And Density

We studied the variety of rape's development index such as development stage, leaves quantity, dry weight, branch quantity, numbers of pods per plant, and searched for the variety of those index how to affect the yield of rapeseed and quality of rapeseed. We also analyzed limiting factors of rape yield by the application of productive potential model. And we chose HuaShuang No.3 as experiment material.1. The difference of the rape development under different sowing dates was obvious, andthe rape yield and quality which related to the rape development also was greatly influenced. As we analyzed, higher yield could be acquired by reasonably sowing earlier in the Yangtze valley since the process of rape's development could be adjusted and the potential of temperature was sufficiently utilized.2. The characters of rape development, such as leaves, dry-weight, height, branch, pods, increased with reasonably earlier sowing date, We also found that there was positive correlation between yield and those character of rape development (for example, the partial correlation coefficient between total growth season and the rape yield was 0.99^**, the correlation coefficient between dry-weight and the rape yield was 0.67^*, the correlation coefficient between the height of rape and the rape yield was 0.86^*, the partial correlation coefficient between the leaves number and the rape yield was 0.98^*) . So the conclusion was, high yield could be achieved by reasonably earlier sowing date.3. Rape with high density treatment attained high yield by higher quantity. We found that the development characters of rape in low density colony, such as leaves, dry-weight, height, branch, pods, was superior so high yield also reached.4. It could be found from the analysis of different production potential in different development stage under different sowing dates that the better application of the sunenergy and high temperature in Yangtze Valley could be realized by reasonably earlier sowing date, and the rape could grow better in the vegetative growth period and escaped from the bad influence of high temperature and the rain in the pods formation period. So all these factors based a foundation for later reproductive growth and high yield. The differences between productive potential under different densities was not obvious.5. Compared the production potential with the rape yields we found that the rape's actual yield only attained 7% of radiation production potential, attained 11% of the thermal production potential, attained 20% of the climatic production potential, so the rapeseed still had greater potential of increase production.6. There wasn't obvious difference between the qualities of rapeseed under different sowing dates and different densities. Therefore, to improving the qualities of the rape should depend on the improvement of breeding and reasonably handling of the fertilization.