Morphological and Biochemical Attributes of Brassica cretica Populations Grown Under Drought Tolerance Conditions

Drought stress is a major constraint on crop productivity in the Mediterranean region. Brassica crops are particularly valued in this region for their adaptability, nutritional benefits, and economic importance in sustainable farming systems. However, their productivity is highly sensitive to water deficits, necessitating the identification of drought-resilient genotypes. This study investigated the responses of five wild Brassica cretica populations and a commercial Brassica oleracea cultivar to a 50% reduction in irrigation, evaluating key physiological traits, leaf nutrient composition, and antioxidant activity. The experiment was conducted in the greenhouse facilities of the Laboratory of Vegetable Production, Agricultural University of Athens. The results revealed significant variation in drought tolerance among the tested populations. Specifically, an ecotype of B. cretica subsp. cretica (C: Akrokorinthos) and B. cretica subsp. laconica (E) showed substantial reductions in biomass, leaf area, and leaf number, whereas B. cretica subsp. aegaea (A: Manikia and B: Ymittos) and another ecotype of B. cretica subsp. cretica (D: Lasithi) maintained stable growth under water-limited conditions. Water deficit also significantly impacted leaf mineral composition, increasing NO3− and Na+ levels while decreasing P, Zn, and Mn. Additionally, drought stress enhanced antioxidant capacity and secondary metabolite production, as indicated by elevated ferric reducing antioxidant power, Trolox equivalent antioxidant capacity, total phenolic content, and total flavonoid content. Notably, the two studied populations of B. cretica subsp. aegaea (A: Manikia, B: Ymittos) and the population of B. cretica subsp. cretica from Lasithi (Crete) (D) exhibit promising drought tolerance, suggesting their potential for cultivation or breeding in water-limited environments. This research contributes to the broader effort of identifying favorable traits in crop wild relatives and to utilize these valuable genetic resources to develop climate-resilient crops for Mediterranean agriculture, where sustainable water use is critical for food security.