Evolution of Soybean Major Agronomy Characters in Huang-Huai-Hai Region

In this study,212 soybean varieties were used to analyze the evolution of soybean yield,quality,agronomy characters and plant type in Huang-Huai-Hai region.The results showed that the number of branches and pods per plant in the varieties bred after 2000 decreased by 26.04% and 1.66%,respectively;while 100-seed weight and fat content increased by 23.17% and 7.32%,respectively,compared with that bred in 1960s.Plant height,the lowest pod height and growth period were the smallest in the varieties of 2000s.Nodes number of main stem in the varieties bred in 1970s were the smallest and decreased by 18.37% compared to that in the varieties bred in 1960s which had the most nodes number of main stem.Protein content was the highest in the varieties of 2000s.The ratio of the varieties with semi-determinate habit to all the varieties was increased steadily and that with indeterminate habit was kept shrinking,however the varieties with dererminate habit are still dominant in Huang-Huai-Hai region.The varieties with round leaf were increased steadily while the varieties with lance shaped and elliptical leaf was reduced.Due to the increase of 100-seed weight,yield per unit area increased although the number of branches and pods per plant decreased with the time.