Abstract:

Drought is one of the main agrometeorological disasters in Heilongjiang. To clarify the response mechanism of soybean to drought, we studied the breeding characteristics of soybean under different drought stress at sowing and seedling stage and flowering and podding stage by using the water control experiment in field. The results show that: seeds emerge slowly at sowing and seedling stage under drought stress, and the factors such as plant height, dry matter of aerial part, dry matter of root, pods number per plant and grain weight per plant are obviously low, and the sterility rate is relatively high, and the sterility rate under the extreme drought is up to 99% higher than that under no drought; soybean plants at flowering and podding stage under moderate drought stress and above have lower photosynthesis volume, shorter plant height and higher sterility rate, and the sterility rate under the extreme drought and severe drought is more than 81% higher than that under no drought; the flowering and podding stage of soybean is sensitive to moisture, the mild drought could cause poor production. In conclusion, soybean under drought stress at seedling stage could have low yield, which mainly results from low germination rate and short growth period, and the following cause is low grain weight per plant and high sterility rate; at flowering and podding stage, the low yield under drought stress is caused by less photosynthetic amount, reduced pods number and grain weight per plant, and high sterility rate.

Key words: soybean, water control experiment, drought, yield, sowing and seedling stage, flowering and podding stage