Molecular approaches for the genetic improvement of cereals for stable production in water-limited environments

Abstract

Drought is a major problem for the production of the world’s five principal cereals: maize, wheat, rice, pearl millet, and sorghum. Past and current breeding efforts have met the challenge posed by drought with some success. With the knowledge generated by those efforts and the emergence of technologies such as structural and functional genomics, the time has come to identify new strategies that combine advanced molecular technologies with conventional breeding and physiological techniques. From June 21 to 25, 1999, a group of 37 scientists from around the world met at CIMMYT Headquarters in Mexico to discuss the problem of drought and to design a strategic workplan that identified and prioritized research activities. The goal of the plan is to accelerate cultivar development leading to improved yields under drought conditions. The strategic workplan drafted by the group of experts includes seven integrated, high-priority approaches for producing drought tolerant crops. The priorities include the following: he characterization of target environments; the establishment and quantification of screening environments and protocols; gene discovery; improved marker system and marker-assisted program integration; bioinformatics leading to improved databases; dissection of physiological traits; and utilization of new genomics-based technology. For each of the approaches, the group developed commodity-specific activities, which provide the basis for future research activities and cross-commodity opportunities. Finally, the group drafted the following four recommendations that it felt represented the major conclusions reached after three days of deliberations. Drought is a major problem especially in developing countries facing the production of the five major cereal commodities: maize, wheat, rice, pearl millet, and sorghum. New opportunities to improve drought tolerance in cereals have emerged with recent developments in molecular technology and genetics. These should be utilized in combination with conv ntional breeding and physiological techniques. As reflected in the seven priorities identified during the workshop, ongoing activities should be improved concomitantly with the allocation of resources for new technologies and research. Integrated approaches across commodities and disciplines have been clearly identified. The time frame for research and product development in different crops, however, may be quite different. In this regard, the following report, which summarizes the objectives, design, and process used for the workshop, should serve as a reference for the development of further initiatives related to drought tolerance improvement in the five target cereals. The anticipated new cultivars and approaches can be used in both developing and developed countries, by resource-poor farmers and researchers.