Unlocking Dolichos bean diversity in the National Genebank: Morphological characterization and core set development to optimize its conservation and utilization

Dolichos bean (Lablab purpureus, L. Sweet.) is a popularly cultivated legume in Asia and Africa for grain, vegetables, and fodder. Although considered a minor or orphan crop, it holds promise in enriching the protein basket of the less privileged across the continents. It has great scope in food and cosmetic, pharmaceutical, nutraceutical, and dairy industries also. Harnessing genetic diversity is crucial for enhancing its productivity. Therefore, the germplasm conserved in the National Genebank (NGB) was evaluated for two consecutive years (2021 and 2022) to trait-wise group the accessions, identify unique traits, and develop a core set that will serve as a working collection accelerating its utilization in research. The experiment revealed 100 bushy and 23 erect stems, 391 erect fresh pod attachments, 23 light green pods, and 125 accessions without constriction which have potential for use in breeding programs. A few accessions with unique traits, IC621846 with the highest hundred seed weight (55.11 g in Delhi and 55.54 g at Hyderabad), IC586957 with the maximum pod width (3.84 cm at Delhi and 4.52 cm at Hyderabad), IC556813 with earliest days to 50 % flowering (36.22 days at Delhi and 34 days at Hyderabad) were identified. The accessions were grouped into 20 distinct clusters. Clustering pattern did not reveal any distinct geographical differentiation. A core set representing 15.6 % (108 accessions) of the entire collection was developed using a heuristic sampling approach. It encapsulated the full range of diversity from the entire collection, evidenced by a 97.44 % Coincidence Rate Percentage (CR%) and an average range retention of 0.98. This curated core set is expected to enhance the utilization of germplasm significantly.