Background: Water deficit stress is considered as one of the most important environmental stresses which is more harmful to strategic crops, as it reduces the final crop yield by up to 40%. Therefore, the aim of this research is to evaluate some promising and superior sorghum entries for water stress tolerance and determine the most agromorphological parameters and reasons responsible for drought tolerance in this regard. Results: Fifteenth sorghum genotypes (five parents and their ten F1 crosses resulting from half diallel analysis) were used in this investigation under two levels of irrigation (normal and drought experiment). The recent genotypes were estimated through some physiological parameters related to water stress tolerance in sorghum; besides that, eight inter-simple sequence repeat (ISSR) primers were used to identify among the five sorghum parents and the highest five crosses resistance to water deficit conditions depending on the data calculated from all studied traits under both conditions. The following genotypes P1, P2, P3, P1 × P2, P1 × P3, P2 × P3, P2 × P4, and P3 × P4 confirmed high resistance to water deficit conditions under the drought treatment compared with the control. This high resistance was affirmed through the calculated data for all studied traits. The ISSR profile analysis showed 151 fragments as taxonomic divisions among the ten sorghum genotypes (38 of them were monomorphic and 113 polymorphic with 74.83% polymorphism). Conclusion: The entries (P1, P2, P3, P1 × P2, P1 × P3, P2 × P3, P2 × P4, and P3 × P4) were succeeded in achieving the highest concept of water deficit resistance under both conditions. Therefore, this work will be the nucleus for producing resistant sorghum varieties for drought stress in the future.

Attempt was made to produce transgenic cell lines of flax cv. Blanka tolerant to drought stress. Genetic transformation systems were used to incorporate the DREB2A gene, as the specific gene for drought stress tolerance. In biolistic transformation, hypocotyl segments were bombarded with DREB2A and GFP genes at particle flight distance of 9 cm and rupture disc pressure of 1300 psi. The expression of the gene was observed under a light microscope after 24 and 48 hrs. In Agrobacterium-mediated transformation, the hypocotyl segments were incubated overnight with Agrobacterium culture at five optical density OD600 i.e. 0.2, 0.4, 0.6, 0.8 and 1 for 30 min with occasional stirring. Later, the explants were transferred to a selection regeneration medium supplemented with 50 mg/dm 3 hygromycin and 300 mg/dm 3 cefotaxime and subcultured every two weeks on a new selection medium. Molecular analysis confirmed the expression of the target DREB2A gene in flax genome.