CROP AND SOIL MANAGEMENT AND BREEDING FOR DROUGHT TOLERANCE

Abstract

Water deficiency is a severe limiting factor in developing several countries and impacts on both economics and food production of these countries. Approximately four tenths of worlds agricultural land is under arid or semi-arid regions with transient droughts causing death of livestock, famine and social dislocation. Water plays a crucial role in the survival of plants by fulfilling the roles of solvent, transport medium and evaporative coolant as well as providing the energy necessary to drive photosynthesis, the natural plant process which synthesizes organic food. Under drought conditions; which can be defined as: the absence of adequate moisture necessary for plant to grow normally and complete its life cycle, the loss of water in the plant protoplasm may result in the concentration of ions in the protoplasm to toxic levels resulting in possible protein denaturation and membrane fusion and negatively impacting plant metabolism. Metabolic changes in response to water stress include reduction in photosynthetic activity, accumulation of organic acids such as malate, citrate and lactate…etc. and overall reduction in protein synthesis. For these entire reasons, drought can cause significant yield reduction. Several agricultural regions are reliant on irrigation to maintain yields. Crop plants which can make the most efficient use of water and maintain acceptable yields will give an advantage in those regions. Research on drought tolerance and mechanisms for improving drought tolerance are underway internationally trying to provide solutions to the problem of water deficiency, which is considered the most complicated problem facing the whole world in the few coming years. That’s will save water used in agriculture and to ensure the development of sustainable agriculture. This includes studies into elucidating the mechanism of drought tolerance in different plants genera and species which have different genetic makeup and hence different abilities for drought tolerance. There are several mechanisms of stress and drought tolerance in plants, so additional studies still required to elucidate the mechanisms by which plants can survive under environments of water deficit. Although genetic basis even on the molecular level for plant tolerance under water stress remains unclear, crop and soil management, breeding programs and molecular biology tools can assist in the screening and identification of new drought tolerant genera and species plants. Also it's necessary to focus on adopting many new crop and soil service processes, which will have a major role in efficient water use, which in its turn leads to increase yield and productivity, and the later should based upon scientific management decisions.