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Montana State University (1987)

A screening technique for evaluating drought resistance of barley (Hordeum vulgare L.) lines

Matin, Mohammad Abdul

Titre : A screening technique for evaluating drought resistance of barley (Hordeum vulgare L.) lines

Auteur : Matin, Mohammad Abdul

Université de soutenance : Montana State University

Grade : Doctor of Philosophy (PhD) 1987

Résumé
Barley is the world’s fourth most important cereal crop after wheat, maize and rice. Much of the world’s barley is produced in regions with climates unfavorable for production of other major cereals. It has persisted as a major cereal crop through so many centuries because of broad ecological adaptation ; it is valued as a feed and food grain. In many arid and semi-arid regions, drought is the most important environmental stress limiting production. In such areas maximum economic production per unit of applied water is essential. In this study, drought-resistant and drought-susceptible barley lines have been examined with the objective of evaluating parameters that may be indicators of drought tolerance under limited water supply. Four cultivars of barley were grown in the field experiment during 1982. Line source irrigation was used to control the moisture gradient. Diurnal determinations of leaf water, osmotic and turgor potentials were made at early heading, late heading and flowering growth stages. Results indicate susceptible cultivars developed greater internal water stress compared to resistant lines. A series of greenhouse studies was carried out during 1984 and 1985 to observe the behavior of root osmotic, leaf water, leaf osmotic and leaf turgor potentials under watering and subsequent drying cycles on three-week-old plants. Resistant cultivars consistently developed higher potentials and quick recovery after watering. Susceptible cultivars reached zero turgor at least one day earlier than resistant ones. Upon analyses of the results of 1982, 1984 and 1985, an intensive greenhouse study was conducted during 1986 on three-week-old plants using ten two-rowed and ten six-rowed barley lines chosen on the basis of resistance or susceptibility to drought. Predawn leaf water potential, relative water content (RWC) and morning and afternoon stomatal diffusion resistance were measured. Predawn leaf total water potential and RWC under stress differentiated resistant cultivars from susceptible ones. These data suggest that the internal water status measurements may be useful selection tools in developing drought-resistant varieties.

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