Selection of oxidative stress-tolerant sweetpotato cultivars for cultivation on marginal lands

Oxidative stress derived from excess reactive oxygen species (ROS) is a major damaging factor for plants exposed to environmental stresses. Sweetpotato [ Ipomoea batatas (L.) Lam] has a relatively broad adaptability to harsh environmental conditions compared to other staple crops. In this study, to select stress-tolerant sweetpotato cultivars for sources of molecular breeding on marginal lands, we eval-uated the ion leakage values in 10 different cultivars after treatment of methyl viologen (MV), an ROS-generating non- selective herbicide, to leaf discs. DPPH radical scavenging activity and the contents of total phenolics were also inves-tigated. The ion leakage of each cultivar showed a diverse value, which is well correlated with DPPH radical scavenging activity of each cultivar. DPPH radical scavenging activity also showed a high corelation with the contents of total phenolic contents. Three cultivars of Yanshu 8, Shinhwangmi and Shinzami showed high antioxidant activity. Our results suggest that a simple and efficient DPPH radical scavenging activity would be a suitable method to select potential cul-tivars with enhanced tolerance to multiple environmental stress.