Evaluation of morpho-agronomic variation among pumpkin ( <i>Cucurbita</i> spp.) landraces in Uganda

Abstract Pumpkins ( Cucurbita spp.) are globally valued for their nutritional, medicinal and economic importance, yet morpho-agronomic diversity among Uganda’s pumpkin landraces remain under-documented despite the favorable agroecological conditions for growth. This study examined 40 landraces (29 of Cucurbita moschata and 11 of Cucurbita pepo ) collected from 18 districts in Uganda under uniform field conditions at Muni University, using 31 morpho-agronomic descriptors. Germination across landraces was conserved, with most sprouting in 6–7 days, while seed weight varied significantly (19.7–52.2 g per 100 seeds), with district-level differences in Central ( F ₇,₁₂ = 3.24, P = 0.03) and Eastern regions ( F ₂,₆ = 6.46, P = 0.03). Seedling traits showed strong differentiation in cotyledon shape, with χ² analysis confirming significant district-level differences in the Central region (χ² = 30.4, P = 0.02). Stem and growth habits ranged from bush to trailing types, with variable branching degree and χ² tests revealed significant differences in landraces among districts from Eastern (χ² = 18.0, P = 0.02). Leaf traits also exhibited notable diversity in blade size, colour intensity, petiole prickles and dimensions, with χ² analysis detecting significant variation in leaf colour intensity of landraces within Northern districts (χ² = 12.0, P = 0.02). Early germination correlated with shorter fruits and smaller seeds; seed weight with seed size; branching with longer petioles and larger leaves. Fruit length and diameter were independent. PCA of 11 traits across 40 landraces explained 38.6% of variation (PC1: 22.0%, PC2: 16.6%). These findings highlight Uganda’s rich but underexplored pumpkin diversity, underscoring the importance of systematic characterization for breeding. The results provide opportunities for selecting high-yielding, disease-resistant and nutritionally superior lines tailored to specific agro-ecological zones. Ultimately, conservation and utilization of these landraces enhances food security, farmer productivity and value chain development, positioning pumpkins as a vital crop for nutrition, livelihoods and sustainable agriculture in Uganda and beyond. Significance of the study What is already known on this subject? Uganda’s pumpkins remain under-documented despite favourable agro-ecological diversity. Local landraces show substantial morphological diversity, offering untapped potential for breeding, food security, nutrition and sustainable agricultural value chain development. What are the new findings? Ugandan pumpkin landraces show conserved germination but significant district-level variation in seed weight, cotyledon, stem, leaf, flower, fruit and seed traits, revealing rich diversity crucial for breeding, conservation and food security. What are the expected impacts on horticulture? The rich morpho-agronomic diversity of Ugandan landraces enables breeding of superior varieties, enhancing productivity, market preference, food security and strengthening horticultural value chains.