Screening sweetpotato (Ipomoea batatas) varieties for tolerance to waterlogging stress

Waterlogging is one of the most damaging environmental stresses for sweetpotato, severely constraining the growth, yield, and overall quality of the storage roots. Hence, identifying potential waterlogging-tolerant sweetpotato varieties plays a significant role in breeding and sustainable crop management in areas prone to waterlogging stress. A screenhouse trial was conducted following a split-plot design with two main plots (waterlogging/non-waterlogging) and 15 subplot factors (varieties) arranged in a completely randomized design. Among waterlogging treatments, significant differences were observed in chlorophyll content (SPAD), vine dry weight, number of storage roots, storage root dry weight, harvest index, and root-shoot ratio. However, no significant difference was found among waterlogging treatments in six parameters: length of the main vine, number of lateral vines, root dry weight, root volume, root length, and total biomass. Waterlogged plants had lower chlorophyll content, heavier vine dry weight, fewer storage roots per plant, and storage roots dry weight, which led to significantly lower harvest index and root-shoot ratio. NSIC Sp36 showed higher root dry weight and root volume, indicating root proliferation under waterlogging stress. NSIC Sp34 showed significantly more storage roots, while the heaviest storage roots were observed in NSIC Sp30, indicating fewer but bigger storage roots resulting in significantly higher total biomass, harvest index, and root-shoot ratio. This indicates NSIC Sp30 and NSIC Sp34 have potential tolerance to waterlogging stress.