Evaluation of Flooding Tolerance of Soybean (Glycine max L. Merr.) in Greenhouse under Upland and Paddy Soil Conditions

Domestic rice production has exceeded the demand in Korea and cultivation of upland crops like soybean has been increased in converted paddy fields. The objective of this study was to investigate the effect of two soil types, upland and paddy, on flooding tolerance of three tolerant and three susceptible soybean cultivars under greenhouse conditions. The flooding tolerance of soybean cultivars was evaluated based on chlorophyll content (CC), plant height (PH), and shoot dry weight (DW) measured under unflooded control and flooded treatments for 14 days. These three parameters were significantly (P < 0.01) affected by the soil type during the flooding and flood recovery periods of 14 days. Mean flooding tolerance index (FTI) of susceptible cultivars was higher than that of tolerant cultivars in upland soil. However, the FTI of tolerant cultivars was greater than that of susceptible cultivars in paddy soil at 14 days after flooding (DAF). A non-significant negative correlation between CC and DW and a significant (P < 0.01) positive correlation between PH and DW were found in both soils, whereas the negative correlation between CC and PH was non-significant in upland soil and was significant (P < 0.01) in paddy soil at 14 DAF. The results suggested that the flooding tolerance level of soybean cultivars could be influenced by soil type hence, it could be useful to consider designing flooding tolerance studies in different soil types. Also, field experiments could be designed to observe data until harvest to verify that with vegetative parameters of tolerant soybean varieties.