Vol. 1, Issue 1, Part A (2024)

Onion (Allium cepa L.) is one of the most economically important vegetable crops in Sudan, cultivated across diverse agro-ecological zones ranging from arid to sub-humid climates. The present study aimed to evaluate the genetic diversity and physicochemical variation among fifteen Sudanese onion genotypes grown across three representative zones-River Nile, Gezira, and South Kordofan-using molecular and biochemical approaches. The genotypes were analyzed for total soluble solids (TSS), dry matter, pyruvate concentration, titratable acidity, and total phenolic content. Molecular characterization was conducted using Simple Sequence Repeat (SSR) markers to assess allelic diversity and genetic differentiation. Results from two-way ANOVA revealed highly significant effects of genotype, location, and their interaction on all studied traits, indicating strong genotype × environment influence. River Nile genotypes exhibited the highest TSS, dry matter, and pyruvate levels, while those from South Kordofan showed lower solids and pungency but higher moisture content. Principal Component Analysis (PCA) effectively clustered genotypes into distinct quality groups, identifying G03, G07, G10, and G11 as elite lines combining high solids and balanced flavor. SSR analysis showed moderate polymorphism (He ≈ 0.50; PIC ≈ 0.47), confirming substantial molecular variability within the local germplasm. The integrated molecular and physicochemical evaluation demonstrated that Sudanese onion populations harbor valuable genetic resources suitable for region-specific cultivar development. These findings provide a scientific foundation for breeding programs aiming to improve onion quality, resilience, and market value across Sudan’s major production zones.