Phenotypic Diversity and Abiotic Stress Tolerance Among (L.) Willd. Accessions.

Bitter vetch ( L. Willd.) is an ancient Mediterranean legume, well adapted to dry climates, that has recently gained attention for its potential in organic farming and as a suitable source of bioactive compounds. This study analyzed the agrobiological variability of 12 bitter vetch accessions from the IPGR-Sadovo genebank in two-year field trials. Yield-related traits were recorded, and grains were assessed for protein, sugar, starch, free amino acids, phenols, and antitrypsin content. Statistical analyses included variance, correlation, cluster, principal component, and path-coefficient methods. Significant variation was observed in plant branching, pod and grain numbers, and grain weight per plant. Grain yield correlated strongly with pod number (r = 0.910**), grains per pod (r = 0.867**) and per plant (r = 0.965**), and pod size. Positive direct effects on grain yield had the traits germination-50% flowering, number of seeds per plant, height to first pod, and harvest index. An indirect impact was found for the number of pods per plant, number of seeds per pod, and seed starch content. Accessions formed four main clusters. BGR6207, B9E0168, and C3000003 showed high yield potential. C3000001, C3000003, C3000007, and C3000006 exhibited early maturity. C3E0118, C3000007, and C3000003 seeds had lower amounts of phenols. BGR13526 presented lower protein and antitrypsin but higher carbohydrate and phenol levels. Tolerance to moderate osmotic stress (150 mM NaCl or 10% Polyethylene glycol 6000) varied. BGR3052, BGR13526, and A3BM0178 were found to be resistant to both stressors, while accessions C3000001 and C3000007 were identified as sensitive to both adversities. C3000006 was determined as sensitive to salinity but resistant to drought, and BGR3051and C3000003 were relatively sensitive to drought but resistant to salinity. Root elongation and thinning were observed in half of the accessions as adaptive responses to stress. These findings highlight some of the advantages of the evaluated bitter vetch accessions for breeding and reintroduction into sustainable agricultural practices.