Physiological Parameters and Drought Tolerance in some F4 Promising-Glaucousness Families of Bread Wheat

Abstract

The selection from segregating generations of hybrid wheat combinations succeeded in developing new genotypes that possess adaptive drought tolerance traits, such as glaucousness. This study was to develop new glaucousness high-yielding recombinants under drought conditions. Twenty-one promising F4 families selected from segregating generations of a cross between a glaucous mutant and an Egyptian cultivar were evaluated for superiority to their parents and the best check cultivar under water stress (WS) and well watering (WW) conditions. A split-plot design with randomized complete blocks was utilized in three replications of the experiment. A total of 25 genotypes were planted in the main plots and two irrigation regimes were assigned to the subplots (21 F4 families, two parents and two check cultivars). Transgressive segregation occurred in yield components and physiological attributes, except for spike length. Based on drought tolerance index values, only eleven F4 families were found tolerant and superior in grain yield/plant (GYPP) to the higher parent and the higher check cultivar under WS and WW. The superiority in GYPP reached in the F4 family No.4 to 43.27 and 55.65 % and 50.31 and 77.86 % over the higher parent and the check variety under WW and WS, respectively. The top seven grain-producing and drought-resistant families have been discovered. Such genotypes were shown to have a high wax content, a high net photosynthesis rate, and a high stomatal conductance under both WS and WW conditions. These F4 families should be suggested to wheat breeders seeking to increase yields under drought conditions.