Table 1

Conditions for dry heatwave simulation in artificial climate chamber

Table 2

Plant growth after dry heatwave simulation at R2 stage of different soybean materials (2019)

Fig. 1

Staygreen syndrome of different soybean varieties induced by dry heatwave simulation for 7 days at R2 stage in 2019

Fig. 2

Staygreen syndrome of Zhonghuang 13 induced by dry heatwave simulation at R2 stage in 2019Note: 2 and 3 are the large views of part A and B in 1, respectively

Fig. 3

Comparison of soybean plants treated by dry heatwave simulation at different reproduction stage in 2020Note: CK: Plants grown in outdoor pots; HT: The potted plants treated by dry heatwave simulation for 7 d, respectively; A, B: CK and HT treatment of Zhonghuang 13 at R2 stage; C, D: CK and HT treatment of Qihuang 34 at R3 stage; E, F: CK and HT treatment of Handou 5 at R4 stage, respectively

Table 3

The secondary growth of soybean plants treated by dry heatwave simulation at different reproduction stage in 2020

Fig. 4

Comparison of pods and seeds sampled from soybean plants treated by dry heatwave simulation at different reproduction stage in 2020Note: Top: pods and seeds of Zhonghuang 13 treated by dry heatwave simulation at R2 stage; Middle: pods and seeds of Qihuang 34 treated by dry heatwave simulation at R3 stage; Bottom: pods and seeds of Handou 5 treated by dry heatwave simulation at R4 stage

Table 4

Soybean agronomic traits under dry heatwave simulation at different reproduction stages (2020)

Fig. 5

Staygreen syndrome without matured seeds in pods

Fig. 6

Staygreen syndrome without pod

Fig. 7

Partial staygreen syndrome

Fig. 8

Staygreen syndrome of whole plant diapause

Fig. 9

Emergence of new leaves and flowers at lower nodes in staygreen soybean plantNote: A: Staygreen plant (Left); B: Control plant; C: Differentiation of flower bud in staygreen plant；D: A downward trend in pod-setting position of staygreen soybean plant