Assessment of Drought Tolerance in Bread Wheat During Germination and Seedling Stages

Plant growth globally faces different limitations, including abiotic limitations. Drought conditions are increasingly turning out to be a common abiotic challenge. The current study attempts to show how germination and early growth stages of wheat varieties can be influenced by drought stress. The laboratory experiment was carried out using a factorial complete randomized design (CRD). Seven common wheat varieties in the Kurdistan region of Iraq (Aras, Adana, Slemani 2, Hawler 2, Hasad, Jehan 99, and Maroof) were tested under five levels of polyethylene glycol (PEG-6000) (0, 5%, 10%, 15%, and 20%). The studied traits were considerably affected by both individual and interactive cultivars and PEG levels. Reductions of 10.6%, 54%, 39.5%, 43.2%, 30.8%, and 37.3% were recorded in seed germination, seedling vigour, root length, shoot length, root weight and shoot weight, respectively at PEG level of 20%. Variety Hasad demonstrated remarkable resilience under intense levels of drought conditions during germination its associated traits. Additionally, it exhibited impressive seedling growth performance under water stress conditions. Among the varieties, Aras stood out for its strong seedling vigour, a crucial trait for surviving drought stress that occurs later in the development cycle. However, Hawler 2 emerged as the variety most significantly impacted by drought stress. Principal component analysis confirmed the results from the analysis of variance and segregated the varieties according to their strength of drought resistance into three groups: resistant varieties (Hasad, Slemani 2, Aras); moderately susceptible varieties (Adana, Jihan 99); and susceptible varieties (Hawler 2, Maroof). The findings of this study can guide breeders in selecting and enhancing resistant varieties within any breeding program, ultimately leading to the development of more resilient wheat varieties to drought stress condition.