This Theme will deliver a unique integration of participatory, conventional, and biotechnological plant breeding methods to attempt major new advances in improving and disseminating drought and salt tolerance in major dryland food and forage crops. Conventional plant breeding and crop physiology have had limited success in achieving these tolerances because of the complexity of the trait-environment interaction, and the variability of these stresses over time and space. But recent scientific advances hold new promise.

Scientists are finding that the genetic maps of different species within broad groupings (such as grasses) are surprisingly similar, a phenomenon known as gene synteny. Comparative genetics tools in grasses (Devos and Gale, 2000), for example now make it possible to apply the collective genetic information from all of the species in a group, to improve any particular species within that group - once a small set of basic genetic tools for that particular species is available. These basic tools are already available, or are well along in the research pipeline for the main dryland crop and forage species.

Our world-renowned partner TIGR (The Institute for Genomic Research) has the technological base and facilities to characterize homologous genetic markers for these crops and forages. ICARDA is contracting with TIGR to develop a generic oligonucleotide-based microarray that can be adapted to allow allele-specific, high-throughput genotyping of any organism at marker loci associated with, or genes controlling, any heritable trait. These stress microarrays will have an expected operational cost of around US$10 per test (approximately 90% less than the commercial cost in the USA). Use of this innovative technology for developing countries will reside in the public domain. This biotechnological approach does not use transgenic methods, which are controversial and could delay or impede the dissemination of research products for impact.

Microarray tests can be affordably run on large numbers of varieties used locally by farmers (including indigenous land races), and this information can be matched against farmer's knowledge and participatory measurements of drought and salt tolerance in their fields, to create an association of marker loci with preferred traits. The favorable genes identified can be quickly pyramided through conventional breeding techniques, and superior recombinants identified through another round of farmer testing. As farmers participate, they become familiar with the germplasm that suits their needs best, and need not later be dependent on formal multiplication and delivery systems for their seed - a widespread constraint in these areas.

Expected outputs for impact include: Haplotype databases; drought and salinity stress microarrays; crop genome databases linked to genetic resources databases and stress phenotyping databases; information on genes, quantitative trait loci and linkage maps; alternative stress tolerance pathways described; sources of salinity stress tolerance and drought stress tolerance identified and characterized that differ in their genetic-mechanistic-physiological bases in target crops; improved breeding populations having locally preferred traits for salt and/or drought tolerance; comparisons of efficiency of component approaches and integrated approaches; experimental and released cultivars; germplasm and seed exchanges; and feedback to integrated breeding programs from participatory trials via biotechnological tools.

Initial core partners

Farmers, ICARDA, ICRISAT, CAZS (participatory methodology), TIGR (oligonucleotide microarrays), CERAAS (drought-West Africa), ICBA (salinity), ICGEB (salinity tolerance genetics).

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