Abstract:

Through the comparative analysis of agronomic characters and quality of three soybean varieties on five sowing dates in northeast Inner Mongolia, the best sowing dates were obtained for the three soybean varieties with high yield and high quality. The best sowing date of high fat variety ‘Mengdou-12’ was May 15, and its yield and quality were the best. The best sowing date of high protein variety ‘Mengdou-13’ was April 27, and the sum of theoretical yield, the content of crude protein, crude fat and total fat in protein were higher than those at the normal sowing date. The best sowing date of high yield variety ‘Mengdou -15’ was April 27 and May 5, and the yield of one-week early sowing was basically the same as that of two-week early sowing, so late sowing was not proper, and the grain quality of early sowing was better than that of late sowing. The comprehensive performance of the three varieties showed that they could be sown early in rainy years. Moreover, the differences of temperature, precipitation and daily temperature range were compared between the best sowing dates and the normal sowing dates, and the effects of climatic conditions at different sowing dates on yield and quality of different varieties were analyzed. Low air temperature and increasing daily temperature range from sowing stage to fruiting stage and less precipitation in the whole growth period are not conducive to the yield formation of ‘Mengdou-12’, but they are beneficial to the yield formation of ‘Mengdou-13’ and ‘Mengdou-15’. Subnormal air temperature from sowing stage to fruiting stage and large daily temperature range in the whole growth period are beneficial to increasing the content of crude fat, crude protein and protein and oil.

Key words: soybean, sowing date, climate, agronomic character, quality