Growth Response and Developing Simple Test Method for Waterlogging Stress Tolerance in Soybean

The global climate changes and insufficient drainage system could cause the flooding with significant yield losses in crop production. Despite the severity of the flooding, the main reason for currently limited research progress is the lack of resistant resources. This study aimed to identify the main indicator to waterlogging stress and suggest a simple screening method for waterlogging resistant variety in soybean. We selected 3 resistance resources and 3 susceptible resources based on the results of mass field screen test, which was previously conducted using about 4,000 soybean genetic resources in RDA. Plant height, stem diameter, leaf chlorophyll content, root weight and adventitious root number and weight were used investigated as indicator. Significant changes by waterlogging treatment was not observed in the plant height and stem diameter. However, the chlorophyll content of first trifoliate leaf and emergence of adventitious roots showed a clear difference between the resistant and susceptible resources after 9 days of treatment, even though the growth of roots was reduced overall by waterlogging. The results indicated that the number of adventitious roots and the chlorophyll content of the first trifoliate leaf were an excellent indicator to distinguish resistance and susceptible resources. We also developed simple screening method for waterlogging in soybean. The resistance resource selection was possible within 6 days after waterlogging treatment in green house using the chlorophyll content of the first trifoliate leaf and the number of adventitious roots. The proposed simple screening method could save the time and labor for large scale field test.