Abstract: 【Objective】 The whole progress of flowering and flower dropping of soybean were observed, and the characteristics and rules of different varieties were analyzed to provide an evidence for high yield breeding and cultivation. 【Method】 Under the conditions of field experiment, the flowering and flower dropping nodes of 72 individuals of six soybean varieties were observed daily (42 days). 【Result】 Flowering process showed a significant ladder of four stages: early florescence is short (about 3 days), less than 4 flowers per day, the flower amount at this stage is 5.73, 4.09% of the total, concentrated in the middle of plants. At full-bloom stage, the daily flowering 5-12 flowers, the duration is longer (12-18 days), the flowering amount of this stage is 108.75, 77.60% of total, the flowering section extends from the middle to the upper and lower ends, and middle-up. At slow florescence stage, the daily flowering 1-5 flowers, the duration is different among varieties, the flowering amount at this stage is 21.24, 15.16% of total, distributed in various nodes of the plant. At late florescence stage, the daily flowering less than 1 flower, until flowering end, the flowering amount is 4.42, scattered on the plants. Flower dropping generally occurs from early florescence 3 days later to late florescence or after late florescence, the flower dropping section throughout the flower section on the plants, the flower-dropping rate at the full flowering stage (36.97%) is less than at the initial flowering stage (51.76%), its slow flowering stage (65.54%), and its final flowering stage (77.96%). The peak of the abnormal abscission about 3-9 flowers daily is correlated with the rainy day and scant sunlight in that periods. In determinate podding habit varieties, the earliest flowering section is in the middle of the plants, and then extend to upper and lower sections, then extend to the bottom 3-7 days later and extend to the top 9-15 days later after flowering. In semi-determinate podding habit varieties, the earliest flowering section is in the middle and lower parts (7th-10th node), and then extend to upper and lower sections, then extend to the bottom 3-7 days and extend to the top 24-26 days later after initial flowering. 【Conclusion】 The flowering amount, flowering node, duration and abscission rate are all different in early florescence, full-bloom stage, slow florescence and late florescence of soybean.

Key words: soybean , flowering , flower drop , temporal and spatial distribution