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Accueil du site → Doctorat → Allemagne → 2015 → Physiological and Molecular Characterization of Kenyan Barley Lines (Hordeum vulgare L.) for Abiotic Stress Tolerance and Malting Attributes

Rheinischen Friedrich-Wilhelms-Universität Bonn (2015)

Physiological and Molecular Characterization of Kenyan Barley Lines (Hordeum vulgare L.) for Abiotic Stress Tolerance and Malting Attributes

Binott, Jayne Jebichii

Titre : Physiological and Molecular Characterization of Kenyan Barley Lines (Hordeum vulgare L.) for Abiotic Stress Tolerance and Malting Attributes

Auteur : Binott, Jayne Jebichii

Université de soutenance : Rheinischen Friedrich-Wilhelms-Universität Bonn

Grade : Doktorgrades (Dr. rer. nat.) 2015

Résumé partiel
Abiotic stresses such as drought, salinity agriculturally poor soils, and inappropriate fertilizer usage as factors of production determining yield and quality of barley for various end uses challenges the production of barley in Kenya. In order to develop appropriate breeding strategies there is a need to understand the physiological, biochemical and molecular processes that lead to observed phenotypes. The effect of increasing salt stress for 3 and 6 days was determined in 14 barley lines used as breeding lines (MN-3, MN-4, MN-5, MN-6, MN-7, MN-8, MN-12, MN-23 and MN-24), those in commercial production (Nguzo, Karne, Sabini) as well as wild progenitors of barley (Hs 2698, HOR 3301) at seedling stage. Changes in important physiological parameters ionic membrane leakage, lipid peroxidation, chlorophyll, and sucrose and GB contents in response to stress showed that reduced ion leakage and MDA and increased chlorophyll, proline, sucrose and GB contents. A reconciled physiological screening clustered Nguzo, MN-24, MN-8, MN-3 as tolerant while Karne, MN-12, MN-7, MN-4 and MN-5 as susceptible cultivars. Expression profiles of dehydrins (Dhn) in roots and leaf tissues of Nguzo, Morex, MN-24, Karne, MN-8 and MN-12 in response to dehydration and salt stress indicated that gene induction depends on the genotype, type of stress, level of stress and the type of tissue targeted. Dhn1 and Dhn9 were exclusively induced by dehydration stress and could be used as potential markers for screening for drought tolerance depending on the choice of tissue. Immunoblot analysis using anti dehydrin anti-sera confirmed the accumulation of low molecular weight DHN which was induced during dehydration and increased salt stress.

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