Variation in root growth responses of sweet potato to hypoxia and waterlogging

Climate change increase the probability of soil waterlogging due to severe rainfall. A low oxygen concentration in soil (hypoxia) is a major problem associated with waterlogging, and root development is an important indicator of resistance. However, little is known about the root development responses of sweet potato to hypoxia under waterlogging. In this study, the root hypoxia tolerance of four sweet potato cultivars was investigated using three environments (hydroponics, soil in pots, and upland field). In the hydroponic experiment, at 4 days after transplanting (DAT), the plants were transferred to either normoxia (control) or hypoxia and grown for 7 more days. In the soil pot experiment, seedlings at 7 DAT were grown for another 7 days under one of two treatments: drained (control) or waterlogging conditions. The root systems of individual plants were scanned with an image scanner using the WinRhizo software to measure root morphological traits. All the cultivars were tested for tuberous root performance under field waterlogging conditions imposed at the seedling stage. The obtained results showed that the root development responses to hypoxia were clearly associated and contributed to waterlogging tolerance in sweet potato plants. Of the four sweet potato varieties investigated, we identified Cuc Nhanh as the most waterlogging-tolerant variety and hence, it was noted as a promising and important genetic plant resource. The results of this study on root responses, hypoxia, and waterlogging relationships are fundamental towards exploring the mechanisms underlying hypoxia and waterlogging adaptation.