EFFECTS OF STORAGE DURATION ON THE QUALITY AND GROWTH DYNAMICS OF SWEETPOTATO (Ipomoea batatas (L.) Lam.) PLANTING MATERIAL IN THE HUMID AGROECOLOGY OF SOUTHEASTERN NIGERIA.

Abstract

Sweetpotato (Ipomoea batatas (L.) Lam.) productivity in humid agroecologies is largely dependent on the quality of vine cuttings used as planting materials. This study evaluated the influence of storage duration of sweetpotato vines on sprout count, plant vigour, and growth dynamics at the National Root Crops Research Institute, Umudike, Nigeria, during the 2024 and 2025 cropping seasons. The experimental site was characterized by low soil fertility, with total nitrogen ranging from 0.109% to 0.19%, organic carbon from 1.08% to 1.107%, and organic matter from 1.86% to 1.904%. Available phosphorus increased from 15.6 to 23.10 mg/kg, while soil pH declined from 5.86 to 4.60, indicating increasing soil acidity that may influence nutrient availability. The cropping seasons were marked by adequate rainfall (1,388.6 mm) and favorable temperature conditions, with mean maximum temperatures ranging from 30.24°C to 31.96°C and minimum temperatures from 21.94°C to 23.01°C. The experiment was laid out in a randomized complete block design with a split-plot arrangement consisting of five storage durations (0, 2, 4, 6, and 8 days) and two varieties (Umuspo-3 and TIS 87/0087), replicated three times. Results showed that shorter storage durations (0 to 2 days) significantly enhanced sprout count and early plant vigour compared to prolonged storage (6 to 8 days). Sprout count declined progressively with increased storage duration, with the lowest values recorded at 8 days. Plant vigour followed a similar trend, although partial recovery was observed at later growth stages. Growth parameter such as number of branches was not significantly affected by storage duration, indicating a compensatory growth response. Sweetpotato virus disease incidence remained low and was not significantly influenced by storage duration. The study concludes that prolonged storage beyond 4 days reduces planting material viability and early crop establishment. Therefore, planting within 0 to 2 days after vine harvest is recommended for optimal sweetpotato production under humid agroecological conditions.