Evaluation Method and Cultivar Selection of Submergence-tolerant Sweet Potato Seedlings

Objective A simple, efficient method to predict the submergence tolerance of sweet potato cultivars was developed.

Method In a pot experiment, changes in color, morphology, and other phenotypic traits of the stems and leaves of sweet potato seedlings being submerged in water for varied durations were monitored. Specific scoring criteria, calculation method, and evaluation scheme were applied to compare the submergence resistance of 72 sweet potato germplasms at seedling stage for tolerance classification.

Results Two flooding durations, 72 h and 144 h, were selected for the evaluation. A scoring system on the stem and leaf phenotypes to quantitatively differentiate the reactions of seedlings to the treatment into 6 classifications was established. Tolerance of the 72 germplasms to submergence varied significantly. More than half of the varieties were relatively tolerant, but 17 substantially. For instance, ‘Zhanshu 118’ and ‘Fushu 404’ were found to be highly submergence-resistant, whereas ‘Quanshu 830’ and ‘Kanghanzhong’ extremely intolerant to the treatment.

Conclusion A double-period treatment method was developed to assess submergence tolerance in sweetpotato seedlings. This approach enabled the screening of 72 sweetpotato germplasms, identifying both highly submergence-tolerant and extremely submergence-sensitive materials, thereby providing a methodological framework and genetic resources for studying the physiological traits and/or breeding of submergence-tolerant varieties.