Response to progressive water deficit in lentil: towards morpho-physiological differentiation between wild accessions (Lens orientalis), landraces and advanced lines (Lens culinaris)

Lentil (Lens culinaris Medik.) is one of the most important food legumes in the world that can contribute to food security and sustainable farming. Drought tolerance is one of the major objectives of breeding programs. This research paper aimed at comparing genotypes with different genetic background (landraces, Lens orientalis wild accessions, and elite advanced lines) under 2 watering regimes (well-watered and progressive water deficit). Drought tolerance was assessed based on morphological and physiological parameters: relative water content and water loss rate of leaves, cell membrane stability, canopy temperature, root/shoot ratio, seedling vigor, wilting severity, and harvest index. The evaluation was carried out in a greenhouse pot experiment using 3 replications. Wild accessions were more drought tolerant than advanced lines and landraces. They had higher root/shoot ratios, relative water contents of leaves, canopy temperature depressions, and cell membrane stability, and lower wilting severity and water loss rate of leaves. In fact, discriminant factor analysis highlighted a clear genetic differentiation for drought tolerance between the 3 genetic groups. Different morpho-physiological responses of the studied genetic material have been observed corresponding to different drought tolerance mechanisms. Wild accessions, advanced lines, and new National Institute of Agricultural Research (INRA) of Morocco varieties A3, A4, A5, A6, and A7, as well as lentil of Zaer, a specific landrace with specific quality mark distinction known in the country, were identified as the most drought tolerant among the studied genetic material. These accessions could be used in genetic improvement programs from the perspective of developing drought tolerant varieties.