Dr. Reena Gupta
The word “drought” is a relative term, and is defined differently by different regions and sources. Webster’s Dictionary defines drought as “a long period of no rain”; though this is an inadequate definition for the water supply industry. Wikipedia describes drought in stages and effects: “As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases”. As drought is a period of time with less-than-normal rainfall and are naturally occurring events. It is often difficult to determine when a drought has begun or ended. The seriousness of a drought depends upon geographic location, weather patterns, soils, water use patterns, and overall water quantity. The greater the demands placed on an area’s water resources, the more serious the drought. Recovery from drought may take months or sometimes years of above average precipitation. Droughts go through three stages before their ultimate cessation.
Meteorological drought is brought about when there is a prolonged period with less than average precipitation. Meteorological drought usually precedes the other kinds of drought.
Agricultural droughts are droughts that affect crop production or the ecology of the range. This condition can also arise independently from any change in precipitation levels when soil conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops. However, in a traditional drought, it is caused by an extended period of below average precipitation.
Hydrological drought is brought about when the water reserves available in sources such as aquifers, lakes and reservoirs falls below the statistical average. Like an agricultural drought, this can be triggered by more than just a loss of rainfall.
Drought is the most devasting abiotic stress that curtails the crop productivity of crops in rainfed areas and most recalcitrant to breeder’s effort. It has been recognized as an important constraint for the better yield of crops since long. In the past, lot of efforts has been made to identify drought tolerant accessions from different sources. Number of breeding strategies was followed to screen out and develop drought tolerant improved cultivars with higher yield potential. Several drought resistant mechanisms and putative traits which contribute to resistance in different crops have been identified, including drought escape via appropriate phenology, root characteristics, specific dehydration avoidance, tolerance and drought recovery mechanisms.
Drought Response
* When drought occurs, the water supplier and community must take action to reduce the demand for water. Reducing water demand can result in significant positive effects within only a few days. A drought response plan can be implemented where good pre-planning has already laid the groundwork for actions.
* To prepare a drought response plan before a drought occurs. This allows time for the plan to receive public review and comment while not in a crisis mode. Contingency planning before a shortage allows selection of appropriate responses consistent with the varying severity of shortages.
* Drought response programs and water efficiency programs are solutions to different actions for such problem.
Suggestions
There is an urgent need for exploration of the plant genetic resources with relevant attributes related to drought resistance in crops and their characterization to facilitate the transfer of desired traits through conventional plant breeding or biotechnological method.
Attention should be given on better understanding of genetic basis of drought resistance through antisense RNA technique, observing the effect of expression level of different enzymes/proteins in different biochemical pathways on drought resistance. A multi-disciplinary approach involving genetics, biochemistry, biotechnology, physiology and plant breeding will be appropriate to assess the complicated and integrated responses of drought and to evolve superior drought tolerant genotypes across the target environment.
Follow our WhatsApp channel