The response of durum wheat varieties from semi-arid environment to drought stress on germination and at the seedling stage

Early drought is a major constraint for cultivating wheat crop in the semi-arid region resulted in poor emergence and weak seedlings and might lead to a complete crop failure under severe drought. The response of eight wheat varieties to simulated osmotic stress was assessed using 10% and 15% polyethylene glycol (PEG-6000), in addition to the control treatment (no stress). Water stress during germination had no effect on the final germination percentages, but it delayed germination with significant differences among genotypes. Results showed that severe osmotic stress (15% PEG) substantially delayed germination; however, mild osmotic stress (10% PEG) had a little effect on germination rate. Furthermore, the results of this study showed that the fastest germinating varieties regardless of osmotic stress level were Acsad 65, Cham I and Ammon. Assessment of coleoptiles and seminal roots demonstrated that HoraniNawawi and Omgais varieties had the longest coleoptiles while Acsad 65 and BaniSuef 6 had the longest seminal roots. The pattern of response of wheat genotypes to osmotic water stress showed substantial differences at the early stage of plant development. Genotypes with a fast germination and a more vigorous root system are very desirable for the rapid establishment of seedlings and their early vigor in the dry areas.