Abstract
The study focuses on the Gui 10 sweet potato variety, with different concentrations of selenium fertilizer applied (0, 4, 8, 12, and 14 mg/kg). The effects of selenium fertilizer on the agronomic traits, nutritional quality, yield, and selenium absorption of sweet potatoes are investigated to determine the optimal selenium supply level for the Gui 10 sweet potato variety, while also providing insights for the development of sweet potatoes. The results indicate that exogenous selenium supplementation increases the number of branches per plant, the longest vine length, and the number of tubers per plant, promoting the absorption of nutrients by sweet potatoes, thereby enhancing yield (by 26%). The contents of soluble sugar and starch show an increase, while the contents of reducing sugar and protein demonstrate a decrease. Additionally, selenium application significantly enhances selenium content in various parts of sweet potatoes, with the order of tuber > stem > leaf > root observed across different selenium application concentrations, indicating that tubers are the most susceptible to selenium accumulation. These findings suggest that the amount of selenium fertilizer has a specific impact on selenium accumulation in sweet potatoes. In conclusion, the optimal selenium application concentration for improving soil fertility, promoting sweet potato growth, enhancing quality, and increasing yield is 16 mg/kg− 1.