Quality Assessment of Farmer-Managed Tropical Pumpkin (Cucurbita moschata Duch.) Seeds in Uganda

Tropical pumpkin (Cucurbita spp.) is an underutilized, nutrient-dense vegetable crop with potential to enhance food and nutrition security and generate household income among farming communities. In Uganda, farmers primarily obtain pumpkin seed through informal seed systems, including farmer-produced and -managed sources where seed quality is largely undocumented. This study evaluated the quality of pumpkin seeds collected from 16 selected districts in Uganda and provides the first baseline assessment of tropical pumpkin seed quality within farmer-produced and farmer-managed systems. Seed quality in this study was defined as the ability of seeds to germinate, exhibit high vigor, and remain free of fungal growth. Pumpkin seeds were assessed at 0, 3, and 6 months of storage under conditions representative of local seed traders (25 ± 5 °C; 60 ± 5% RH). Seed-associated fungi recovered on PDA containing streptomycin sulfate after 14 days of incubation were identified morphologically. Seed purity ranged widely (43.8–99.5%), indicating substantial variability among seed sources. Seed germination varied among districts, with most seeds showing improved germination after storage, whereas seed vigor declined with storage duration. Five putatively seedborne fungal genera, Fusarium, Aspergillus, Colletotrichum, Alternaria, and Rhizopus spp., were identified. The findings demonstrate substantial heterogeneity in farmer-produced and -managed seed, which is a predominant seed source in Uganda.