Some Morpho-Physiological Characters as Indicators of Water Deficit Tolerance in some Bread Wheat Genotypes

Wheat (Triticum aestivum L.) represents a fundamental cereal crop in Egypt. In the context of ongoing climate change and escalating population growth, enhancing wheat resilience to abiotic stresses, particularly drought, has become imperative for maintaining stable and sustainable yields. This research was undertaken at the El-Gemmeiza Research Station to investigate the responses of diverse bread wheat genotypes to soil water deficit stress, utilizing selected morphological and physiological traits as evaluation criteria. The experimental design followed Randomized Complete Block Design (RCBD) with three replications. Ten wheat genotypes were assessed under two irrigation regimes: (1) well-watered conditions and (2) water-deficit conditions. The results indicated that water deficit stress significantly influenced all measured traits. However, genotypic variability exerted a more pronounced effect on the observed morphological and physiological responses. Genotypes such as Gemmeiza 12, Misr 3, Misr 1, Giza 171, Sids 14, and Line 3 exhibited superior adaptability under drought stress. These genotypes maintained relatively higher values in grain yield, total chlorophyll content (Chl a+b), osmotic potential, shoot dry matter accumulation, and water use efficiency, suggesting enhanced drought tolerance mechanisms. The identified morpho-physiological traits proved to be reliable indicators for screening drought-tolerant wheat genotypes. Furthermore, selection efficiency can be significantly improved when multiple complementary traits are evaluated in combination rather than in isolation. To support breeding efforts targeting drought tolerance, it is crucial to validate the stability and expression of these traits across diverse environmental conditions.