| Abstract |
In agriculture, the term drought refers to a meteorological condition in which the amount of water available through rainfall and/or irrigation is insufficient to meet the crop needs for optimal growth and development. This eventually affects overall productivity. Rainfed crops grown during the summer-rainy season in the tropics occasionally face extreme weather conditions. These extreme weather conditions translate into various abiotic stresses, such as intermittent/contingent drought, which constitutes one of the key abiotic constraints for crop production in many parts of the world. The erratic distribution pattern of rain in the tropics due to inter-annual variability occasionally causes prolonged dry spells at different crop growth stages, which results in poor crop growth and development and eventually poor yields. Crop breeding programs targeting drought tolerance using conventional and/or molecular breeding approaches rely heavily on high-quality phenotypic data generated under drought stress. One of the key prerequisites for generating a quality drought phenotyping data is accuracy and precision in managing drought stress in field phenotyping, so that genotypic variability could be expressed and precisely identified. Applying drought stress at required intensity with uniformity and precisely at targeted crop stage has been a major challenge, especially under field conditions, as several weather factors interact and affects the stress development and its intensity. Occasionally, the managed drought stress trials ended with either low or too severe stress, which is often realized after completing the trial. In this manual, the quantitative approach of managing drought stress with required intensity at targeted crop stage (for example – flowering stage), and with uniformity over space (across plot) and duration is discussed. This manual is developed for field crop breeders, crop physiologists, agronomists, masters or Ph.D. students and field technicians who are working on phenotyping and/or selection for drought stress tolerance in field crops. |
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