Assessment of Salinity Tolerance and Ecotypic Variability in Vicia narbonensis L.: Morphological, Physiological, and Biochemical Responses

Salinity stress is a major challenge for global agriculture, particularly in arid and semi-arid regions, limiting plant productivity due to water and soil salinity. These conditions particularly affect countries along the southern Mediterranean rim, including Algeria, which primarily focuses on pastoral and forage practices. This study investigates salinity tolerance and ecotypic variability in Vicia narbonensis L., a fodder legume species recognized for its potential to reclaim marginal soils. Morphological, physiological, and biochemical responses were assessed in three ecotypes (eco2, eco9, and eco10) exposed to different salinity levels (low, moderate, and severe). The study was conducted using a completely randomized block design with three blocks per ecotype per dose. The results from the two-way analysis of variance demonstrate significant effects across nearly all attributes studied, revealing distinct ecotypic responses. These findings underscore variations in growth parameters, osmotic regulation mechanisms, and biochemical adjustments. The substantial diversity observed among these ecotypes in their response to salinity provides valuable insights for breeders addressing both agronomic and ecological challenges. Multivariate analyses, including Principal Component Analysis (PCA), revealed key variables distinguishing between ecotypes under salinity stress. Moreover, Classification based on Salinity Tolerance Indices (STI) further differentiated ecotypic performance with more precision, and this is because of the combination of the different parameters studied. These results open up new prospects for the development of strategies to improve the salinity tolerance of forage legumes.