|Recent interest in the genetic improvement of crop drought resistance by conventional breeding and molecular techniques underscores the urgent need for standard assays of drought resistance. The lack of such standards is becoming a major obstruction to the proper assessment of genetic modifications towards drought resistance. This presentation offers a conceptual framework for defining and developing a standard testing system for drought resistance. It is an invitation to pursue a pragmatic discussion towards the creation of standards. The main postulate put forward is that the test of drought resistance must be performed with whole plants and/or plant communities, even if compe1ling evidence for the prevalence of high resistance can be derived or implied from data at lower levels of plant organization.|Drought resistance is attained within three major physiological domains: (a) the maintenance of a high (favorab1e) plant water status during stress; (b) the maintenance of plant function at low (unfavorable) plant water status, and (c) the recovery of plant water status and plant function after stress. Possible tests are discussed for each domain, in terms of principles, problems and possible solutions, but not in terms of the final protocols. The integrated response to drought stress in terms of plant production must be tested in the field. An outline of the available field-tests for assessing plant production under drought stress is summarized.|It is conc1uded that any c1aim for a genetic modification of stress resistance that is presumed to impact crop performance in agriculture wi1l remain on paper unless proven with whole-plant testing systems and under field conditions. It is our responsibility to agree upon a standard testing system to serve this purpose.

English

0101|AL-ABC Program|AGRIS 0101

Jose Juan Caballero

CIMMYT Publications Collection