Drought adaptation refers to a crop’s ability to develop satisfactorily under water stress. Adaptation is the modification of a plant’s structure or function in order for it to survive and reproduce in a specific environment. Crops primarily survive and thrive under moisture stress in two ways:
(I) escaping drought and (II) drought resistance
(I) Escaping Drought
The simplest way for plants to adjust to dry soil conditions is to get out of the drought. Ephemerals, like many desert plants, have a very short life span (5 to 6 weeks). As a result, they germinate at the start of the rainy season and finish their lifetime by the conclusion of it. Because these plants lack a method for dealing with moisture stress, they are not drought tolerant. Germination inhibitors act as a safety net.
The ability of a cultivar to develop before the soil dries is the main adaptation to dry-land growth in cultivated crops. Short-duration pulses such as cowpea, green gramme, and black gramme might be included in this group, as can certain kinds of pearl millet that mature within 60 days of seeding.
Drought resistance refers to a crop species’ or variety’s capacity to thrive and yield satisfactorily in places with frequent water shortages. Plants can adapt to drought by avoiding or enduring stress through a variety of ways. Drought resistance is provided by these systems.
– Avoiding Stress: The ability to maintain a positive water balance and turgidity even when subjected to drought conditions, so avoiding stress and its repercussions, is known as stress avoidance. Under drought conditions, a favorable water balance can be achieved by conserving water by limiting transpiration before or as soon as stress is felt, or by accelerating water uptake sufficiently to recover the lost water.
– Drought tolerance with low tissue water potential: The plant’s ability to withstand periods of low tissue water potential and periods of no significant rainfall. They can develop seeds on a restricted water supply because they may produce flowers with minimal vegetative structure.
– Mitigating stress: The ability of plants to transfer assimilates collected prior to seed filling to the grain during the seed filling stage is an important feature of developmental plasticity. When there is enough water, the food components stored in the stems and roots are provided to the grain in small amounts, but when stress occurs during the seed filling stage, a higher proportion of the previous assimilate is transported to the seed.