干旱区生态环境知识资源中心

Limitation of water Is major abiotic factor affecting crop productivity in different parts of world. Climate change is likely to make drought stress even more severe in the future, particularly in semi-arid and arid tropics. Therefore, development of crops with better adaptation to water stress is very critical to have sustainable crop production. An attempt is made here to assess different approaches undertaken to enhance crop performance under water-limited conditions. Improving drought tolerance during reproductive phase is often a high priority in crop breeding programmes targeting drought-prone areas. Empirical approach followed in different crops to enhance drought tolerance has mainly addressed the issue of environment for selection and of criteria for improving drought adaptation. Using evaluation data from drought stressed and non-stressed environments, many studies highlighted importance of evaluation and selection in drought-prone locations. Most physiological research has concentrated on the identification of parameters that have found little place in regular breeding programmes owing to the lack of simple and easy techniques for selecting such characters on a large scale. Use of adapted germplasm has played a pivotal role in developing drought tolerant crops. The introgression of elite genetic material into drought-adapted germplasm has also been established as an effective approach to enhance performance under drought without compromising performance under stress-free environments. Molecular breeding is fast emerging as a supplement approach to enhance drought adaptation at a faster rate with greater precision. Efforts in this direction started with the development of a molecular marker-based genetic linkage maps in major food crops followed by identification of quantitative trait loci (QTL) determining yield under drought environments. Further success would depend upon development of repeatable, low-cost, high throughput phenotyping procedures that reliably characterize genetic variation for drought tolerance and its component traits.