BIOCHEMICAL AND PHYSICAL CHANGES DUE TO DROUGHT STRESS IN WHEAT(Triticum aestivum L.)

Wheat is the major staple cereal crop of the world population. In developing countries like Nepal, cultivation of wheat is dependent upon the monsoon and the irregular monsoon gives way to the drought condition. The studies and researches of recent years have found pronounced effect of drought on the wheat production. The drought stress in crop leads to several changes in the physiological, morphological and biochemical traits leading to the economic losses. The morphological changes can be viewed through two ways as change in shoot and root system such as effect on plant height, leaf senescence, flowering and so on. Similarly, physiological changes involve change in cell growth pattern, chlorophyll content, photosynthesis disturbance and biochemical changes occur in concentration of different chemicals and activity of different enzymes, hence resulting alteration in the natural processes in different phenological stages of wheat. To reduce the effect of drought stress, various approaches have been made but the more focus has been given in the identification of traits that yields high rather than introducing those traits which show better responses towards environmental irregularities. This review study is done to assess the various changes in characters of wheat due to drought and their effect on the crop yield and productivity.