Cultivar-Specific Responses of Sweet Potato Leaf Nutritional Quality to Nitrogen Application Rate and Water Availability

Sweet potato (Ipomoea batatas) is an important crop with moderate tolerance to water stress. Understanding its antioxidant properties and nutritional content under various environmental stressors is vital for optimizing their nutritional value and resilience. Antioxidants like carotenoids, anthocyanins, and polyphenols are health benefits of sweet potatoes. Although previous studies have examined the nutritional components of sweet potato leaves and roots, comparative analysis of antioxidant activity and nutritional content among different cultivars under environmental stress conditions remains limited. Our study examined the antioxidant properties and nutritional content of three sweet potato cultivars, Georgia Jet, Jasmin, and Line 11-88 (recently released by LSU AgCenter) under various environmental stresses including Control (100% Nitrogen +100% water), Nitrogen stress (60% Nitrogen + 100% water), Drought stress (100% Nitrogen + 60 water), and the Combined stress of nitrogen and water (60% Nitrogen + 60% water). Nutritional content was quantified across cultivars and treatments in the leaves. Anthocyanin content varied significantly across cultivars and treatments. Jasmin had the highest response under both nitrogen and combined stresses, Line 11-88 highest under control, and Georgia Jet remained relatively low and stable across all treatments. Flavonoid content was not significantly affected by stress treatments but was higher in Georgia Jet and Jasmin compared to Line 11-88. Polyphenol content was highest in Jasmin under Control and Combined stress but remained consistent across treatments for Georgia Jet and is generally lower content for Line 11-88. The results suggest that Jasmin is the most promising cultivar in terms of antioxidant properties, making it a potential source of nutritional and functional food in sweet potato leaves.

This study explores how nitrogen and water availability variations impact sweet potato leaves' nutritional quality. Our study shows that nitrogen and water as limiting factors can cause an increase in the nutritional content of sweet potato leaves.