استخدام تقانة الاستجابة للتحريض في سبر التباين الوراثي لتحمل الجفاف و الحرارة المرتفعة لدى بعض طرز زهرة الشمس في طور البادرة الفتية

الملخص EN

A laboratory experiment was conducted to assess the response of six sunflower genotypes for osmotic and heat stresses, to screen the highly tolerant genotypes using the temperature induction response technique (TIRT) at the seedling level, beside studying the relevance of stepwise transfer to increase the tolerance of the induced seedlings with the sub-lethal levels of both osmotic as well as heat stress, when they are exposed to'the lethal levels of these stresses.

Another experiment was carried out to evaluate the functional and molecular applications of the cross protection concept.

There was a genetic variation in the response of the investigated sunflower genotypes to osmotic as well as heat stresses during the seedling stage.

The two genotypes Allstar and C207 were more tolerant to both osmotic and heat stresses, while the remaining genotypes, especially Alison and Sarghai1 were more susceptible.

The length of root and shoot was significantly the highest in the osmotically and heat (Gradual induction: 35 Cº-1 hr 40 Cº-1hr 45 Cº-1hr) induced seedlings, indicating the importance of induction or the pre-exposure of seedlings to the sub-lethal level of stresses in enhancing the ability of seedlings to endure the lethal levels of stresses.

There was positive significant correlation (r = 0.94**) between the performance of the seedlings under the two investigated stresses, indicating the validity of the applied technique.

Results showed the possibility of presence of general and specific molecular defense lines.

The thermal induction signal was found to be more effective than the osmotic induction one, where it could activate the expression of genes responsible for the synthesis of stress responsive proteins, which can acquire tolerance to both investigated abiotic stresses.