**1. Introduction**

Any inimical condition or substance that affects plant's metabolism, growth and development is referred as stress. Basically, stress is an altered physiological condition caused by different living and non-living factors which disturb the equilibrium. Plants are frequently posed with a plethora of stress conditions such as drought, salinity, heat stress, low temperature, heavy metal toxicity, flooding and extremes of soil pH. Plants also face challenges from biotic factors like pathogens, insects etc. These types of abiotic and biotic factors limit plants growth and productivity. The non-living variable must impact the environment beyond its normal range of

variation to unfavorably affect the population performance or individual physiology of the organism in a significant way.

Drought is a meteorological term and defined as a period without significant rainfall. Generally, drought stress occurs when the available soil-water becomes scanty and atmospheric conditions cause continuous loss of water by transpiration or evaporation. Water deficit is one of the major abiotic stresses, which adversely affects crop growth and yield. These changes are mainly associated with altered metabolic functions, one of those is either loss of or diminished synthesis of photosynthetic pigments, uptake and translocation of ion, carbohydrate biosynthesis, nutrient metabolism and synthesis of growth promoters. These changes in the metabolic functions and synthesis of photosynthetic pigments are closely related to biomass production in plant [1]. A common adverse effect of water stress on crop plants is the reduction in fresh and dry biomass [2]. Plant productivity under moisture stress is strongly associated with the processes of dry matter partitioning and temporal biomass distribution [3]. Previous study about different crop species faces huge yield reduction due to drought stress (**Table 1**). We have aimed to discuss the crops' response and adaptive mechanisms to combat drought stress and also genetic interventions which may help developing cultivars suitable for water-scarce conditions.
