Effects of Different Sowing Dates on Soybean Varieties Quality in Different Maturity Groups
To clarify the impact of different sowing dates on soybean quality,this study used 20 soybean varieties from different maturity groups(early,middle,and late)in Northeast China as experimental materials to explore the changes in quality indicators such as soybean protein content,fat content,and total protein+fat under different sowing dates(May 13,May 23,June 2,June 12,and June 22).The results showed that,overall,delaying the sowing date for less than 10 days had a relatively small impact on soybean quality.Delaying for 10-20 days had a greater impact on protein content than on fat content.Delaying for more than 20 days resulted in significant or extremely significant differences in various quality indicators compared to the first stage.When delaying for 40 days,both protein and fat content significantly decreased,reaching the lowest value.This study further analyzed the response of soybean quality in different maturity groups to delayed sowing date.The results showed that the trend of changes in soybean quality indicators with delayed sowing date was closely related to the number of growth days(i.e.maturity)of the variety.There were significant differences between different maturity groups.The later the sowing date was delayed,the greater the decrease in average protein content of the early maturing group of soybeans.The protein content of the third and subsequent periods decreased significantly compared to the first period(May 13).The protein content of the medium and late maturing groups of soybeans was not significant before June 2 and June 12,respectively;The fat content of late maturing group soybeans significantly decreased with the delay of sowing time,and the decrease gradually expanded.The fat content of early maturing group and medium maturing group soybeans did not reach a significant level on June 2 and June 12,respectively;The total amount of soybean egg fat in different maturity groups generally decreases with the delay of sowing time,and its downward trend is basically consistent with the change pattern of protein content.That is,the total amount of protein+fat in the early maturity group of soybeans significantly decreases when sown more than 10 days later,while the total amount of protein+fat in the middle and late maturity groups of soybeans is relatively stable when sown on June 12th and June 2nd,respectively;When different maturity groups of soybeans are sown late for more than 30 days,all quality indicators will show a serious decline.This study provides important reference for predicting the quality of late sown soybeans in Shenyang area.