اعلانات هامة

A laboratory study was conducted in order to evaluate the response of some bread and durum wheat genotypes to osmotic stress at the seedling stage by using a the osmotic induction response technique (OIR), to assess the effectiveness and validity of the proposed screening tool in identifying the stress tolerant genotypes, through comparing the performance of the investigated genotypes at both seedling stage and plant level in the field under drought conditions, in addition to the evaluation importance of induction stress in improving the tolerance of the osmotically-induced wheat seedlings to the lethal levels of osmotic stress. The field experiments were laid according to randomized complete block design (RCBD), while the lab. experiment was laid according to complete randomized design(CRD) with three replicates for both of them. Statistical analysis results revealed significant variation in the response of the investigated wheat genotypes to osmotic stress at seedling stage, where the bread wheat varieties (Cham6, Cham4, and Douma2), and the durum wheat variety Acsad65 were classifies as highly osmotic stress tolerant varieties, while the bread wheat variety (Safeet1), and the durum ones (Barkha, Cham3, Cham5 and Khareem) were classified as highly sensitive varieties.  It has been noticed that the length of roots and seedlings (roots + shoots) was significantly higher in the osmotically-induced seedlings (12.20 and 17.72 cm respectively), while the length of such traits was significantly lower in the non-induced seedlings, which were transferred directly to the lethal level of osmotic stress (6.96, and 8.42 cm respectively), and the reduction percentage of  the length of roots and seedlings was significantly higher in the non-induced seedlings (69.78 and 69.25% respectively), while it was significantly lower in the induced seedlings (47.02 and 35.28% respectively), indicating the relevance of induction in improving the tolerance efficiency of the seedlings exposed to the lethal levels of osmotic stress. There was a positive significant correlation between the average seedling length and grain yield    (r = 0.70٭), assuring the effectiveness of the proposed screening tool to differentiate the drought tolerant varieties from the susceptible ones. 

Key words: Osmotic stress, Screening tool, Induction, Early seedling vigor, Grain yield, wheat.

نُفذت دراسة مخبرية بهدف تقييم استجابة بعض طرز القمح الوراثية للإجهاد الحلولي، في طور البادرة الفتية، باستعمال تقانة الاستجابة للتحريض الحلولي