10th U6+ Consortium of African Universities International Conference

Lablab purpureus (L.) is an underutilized, drought-tolerant legume with significant potential to enhance local food and feed systems. However, its widespread integration into farming systems is constrained by a narrow genetic base, late maturity, and low farm-level grain yields <1,000Kgha-1. This study utilized gamma irradiation to induce genetic variation, evaluate heritability, track molecular diversity, analyze seed composition, and establish yield stability across environments. Bulk seeds of four elite Kenyan genotypes were irradiated with 300 Gy and 400 Gy gamma rays and advanced via pedigree selection to M4 generation. Exposure to irradiation significantly modified vegetative and yield-related metrics (P≤0.05) across all lines except Eldo Kt Black I, which exhibited pronounced radio-tolerance. Heritability estimates proved that key quantitative traits among Lablab are governed by additive gene action. Genomic screening of 95 sub-selected M4 mutants using 20 SSR markers generated 105 alleles with a mean PIC of 0.58. Analysis of Molecular Variance showed that 55% of the genomic variance resided within individual lines and 45% between mutant groups. Proximate evaluations confirmed significant nutritional improvements (P ≤0.05), accession BF032 achieved peak crude protein 28.86%, while WT018, BT114, and BT039 concentrated exceptionally high phosphorus, potassium, calcium, and zinc. Multi-locational yield stability validations of 24 elite lines in selected North Rift agro-ecologies demonstrated significant genotype-by-environment interactions. One premier; WT026 (4462.10Kgha-1), climate-resilient mutant accession outperformed all lines and checks. Baringo was identified as the optimal environment for high-yielding Dolichos production. These results demonstrate that gamma irradiation is an efficient strategy to induce valuable agronomic variations and secure local food systems.