Yield and Quality Change from 50 Years of Genetic Improvement of Soybean Cultivars in Heilongjiang Province

In Heilongjiang Province,soybean cultivars released in the post 50 years were selected for yield and quality investigation in this study.The results showed that there was significantly relationship between yield and year of cultivar release,and the soybean yield increased by 1.27% per year across the period.The yield increase was contributed to the pod number,seed number per pod,seed number and harvest index,but not to 100-seed weight.With the 50-year genetic improvement,protein and fat concentration did not change greatly and their CV was relatively small.Leaf nitrogen concentration,leaf nitrogen content,specific leaf nitrogen and LAI(Leaf Area Index)at R2 stage(full flower stage)were not associated with yield and quality.However,the plant dry weight at this stage had minus co-relationship with yield,indicating that accumulation of dry mater during vegetable stage do not affect the yield.