Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Molecular and morphophysiological approaches for a better understanding of drought resistance mechanisms in some wheat genotypes

Auteur : Abdelgany Hamed, Ahmed Mohamed Elghareb

Université de soutenance : Sabanci University

Grade : Doctoral Thesis 2010

Résumé
Drought resistance is the main challenge of wheat genetics and breeding programs. Resistance is a complex mechanism involving physiological, biochemical, and molecular processes. The effects of drought on these processes were studied in four bread wheat (Triticum aestivum) genotypes (Sahal-1, Giza-163, Ozcan and BVD-22) that were selected from a screening study. The selected genotypes were grown in the greenhouse and subjected to water deficit induced by withholding water supply for one week, at three different growth stages :-40, 60 and 80 days after sowing. The results revealed that 1) drought adversely effected the plant height, biomass, number of leaves per plant, leaf and soil water content, macro and micro nutrients concentration whereas proline accumulation, soluble carbohydrate, lipid peroxidation, and antioxidant enzymes activities except catalase were positively affected ; 2) Drought resistance was almost seen in Sahal-1 and BVD-22 genotypes but its extent varied from one genotype to another and even within genotype from growth stage to other stages. Differential display technique was used to study the expression profile of Sahal-1 and BVD-22 which was exposed to drought at 40 DAS. We observed ten differentially expressed genes. These fragments were isolated, cloned, sequenced, and compared with nucleotide and protein sequence databases using BLASTN and BLASTX algorithms. Under field condition, the response of forty-nine wheat genotypes to drought significantly reduced the plant height, biomass, harvest index, NDVI, SPAD, and yield components as well as delayed the heading date, and increased canopy temperature of most genotypes.

Mots clés : Drought. — Proline. — Lipid peroxidation. — Soluble carbohydrate. — Antioxidant enzymes. — mRNA DD. — SPAD. — NDVI. — Canopy temp. — Harvest index. — Biomass. — Yield. — Susuzluk. — Kuraklık. — Prolin. — Lipit peroksidasyonu. — Çözünebilir karbonhidrat. — Antioksidan enzimler. — Kanopi derecesi. — Hasat endeksi. — Biokütle. — Verim.

Présentation