"Drought stress accounts for more production losses than all other factors combined" John Cushman, Biochemistry Professor at the University of Nevada, Reno.

Agricultural plant science has had two main goals for decades: to increase yield and quality of agricultural products and to improve the protection of crops from diseases or limitations caused by pathogens, insects, nutrients and stress. These goals have significant economic implications, which are affected by environmental conditiond

As the Earths population increases, new means of improving crop productivity must be found to increase the resources available. Presently farmed areas are affected too. Already, intensive irrigation in agriculture production has resulted in severe salinity problems in the USA, Israel and other countires. Futhermore, in the USA and several developing countires, major problems relating to drought, high and low temperatures, and are already limiting agricultural productivity.

One way of doing this is to develop crops that are more tolerant to such stresses as drought, flooding, heat, radiation, salinity, chilling and freezing, so that new land can be brought under cultivation. With the use of stress tolerant plants, there will be the possibility of using a lower quality of irrigation water with a higher salt content. It may be possible to use less water over the course of the season which would be an important factor as farmers face increasing competition for water resources from municipal users (Holmberg, N. and Bülow, 1998).

The goals of agricultural plant science are to increase crop productivity and the quality of agricultural products and to protect the environment by maintaining a system of sustainable agriculture that preserves the ecological basis of plant production. The inherent diversity among plant species demonstrates clearly that plants are able to adapt to environmental stresses using genetically based programs. Crop improvement, i.e. the optimisation of plant features and performance according to agricultural needs, has been undertaken for hundred´s of years: agronomists, breeders, and gardeners have used classical plant breeding methods based on selection of natural variants to improve genetic sources.

Methods and techniques developed in molecular biology in recent years, especially reliable transformation systems for essentially all crops and growing numbers of complete genome sequences of higher plants are providing tools to support plant breeding strategies and allowing scientists to tackle as yet unsolved problems or to speed up breeding programmes. Such tools will extend plant breeding by introducing new, unanticipated traits, in order to develop plants in which both crop productivity and stress tolerance are enhanced.