Variations in Morphological and Tuber Attributes of Sweet Potato (<i>Ipomoea batatas</i>) Varieties in Response to NPK in Ogbomoso, Nigeria

Sweet potato (<i>Ipomoea batatas </i>(L.) Lam) is an essential resource for rural people due to its nutritional value, drought tolerance, and ability to adapt to various soil and climatic conditions. Despite the importance of sweet potato as a food crop, the low yield of this crop is caused by many factors such as low soil fertility of most arable fields, lack of improved varieties resistant to diseases, and good genetic traits. Therefore, as a result of low soil fertility in Nigeria, the soil must be supplemented with adequate macro-nutrients to improve and sustain the growth and yield of sweet potato varieties. This study examined the influence of NPK fertilizer application on the morphological characteristics and tuber yield of selected sweet potato varieties cultivated in Ogbomoso, Nigeria. Carried out at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso. It involved six sweet potato varieties (Ex-Igborian, Mother Delight, Butter, Tis 82/0087, King Jane, and Shaba) and two NPK rates (0 which is control, and NPK rate of 50 kgN, 11 kg P<sub>2</sub>O<sub>5</sub> and 20 kg K<sub>2</sub>O ha<sup>-1</sup>) arranged in a 2X6 factorial experiment fitted into a randomized complete block design and replicated three times. Data were collected on growth parameters and yield attributes, and they were subjected to analysis of variance and means separated using the Least Significant Difference at a 5% probability level. Results showed that NPK fertilizer significantly (p=0.05) influenced the growth parameters such as vine length (84.60cm), number of leaves (54.70), and number of branches (11.70) obtained from plants under NPK application while control gave the least values. Fertilizer application had a significant effect (p=0.05) on the yield and yield attributes of sweet potatoes. Therefore, Mother Delight and Ex-Igborian with the application of 50 kgN, 11 kg P<sub>2</sub>O<sub>5</sub> and 20 kg K<sub>2</sub>O ha<sup>-1</sup>can be recommended for optimum performance of sweet potato in the study area.