TOWARDS IN VITRO SELECTION STUDIES FOR DROUGHT TOLERANCE IN WHEAT

Abstract

Wheat is the second most important cereal crop in the world. The main target of the agricultural policy, in Egypt, is to increase the wheat production, in specific, as well as the other food crops in general to decrease the gab between wheat production (50-55%) at the annual requirements (about 10 million Ton). Wheat production under limited rain or minimizing the irrigation requirement became an objective in Egypt as well as many areas worldwide due to increasing limitation on water supply. Conventional breeding method for droughttolerancein wheat is a difficult and long-term project (Winter et al.,1988). Methods of biotechnology had been suggested to accelerate developing new cultivars high in yield and more tolerant to compact environmental stresses (Khush and Virmani, 1984). In vitro selection for· tolerance to environmental stresses presents an excellent opportunity to assess the direct application of tissue culture techniques to crop improvement. Genetic variation can be enhanced by cell and tissue culture through clonal variation. Mutation rate resulting from somaclonal variation increased up to 5% at a specific gene frequency in comparison to 10-° in the M, populations (Brock, 1979; Larkin and Scowcroft, 1981).