Mobilizing Useful Biodiversity from Gene Bank into Wheat Breeding Programs for Varietal Improvement

Increased future demand for food and slow rate of genetic gain for yield are concerns that have led the United Nations’ Food and Agriculture Organization to call for increased use of on-farm and gene bank biodiversity. The gene bank at the International Center for Maize and Wheat Improvement (CIMMYT) contains 140,000 accessions of wheat, including landraces, wild relatives, synthetics and elite wheat genotypes that are adapted to major wheat growing environments of the world. CIMMYT’s ‘Seeds of Discovery’ project is making large-scale efforts to unravel the value of this resource and to mobilize useful variation into breeding pipelines. This includes genotypic characterization of 35,000 gene bank accessions and 15,000 breeding germplasm through genotype-by-sequencing (DArTseq technology), and phenotypic evaluation of 70,000 accessions for heat and/or drought tolerance, 22,000 for grain quality, 10,000 for diseases, 2,000 for phosphorous use efficiency (PUE), and 900 synthetic wheats for biomass and yield potential. Diversity profiles from landraces of Mexico (10,000), Iran (3,000) and other countries revealed useful information for pre-breeding. Trait donors for heat, drought, PUE, yellow rust, Karnal bunt and various grain quality traits were identified. This wealth of genetic and phenotypic information was used to develop an array of pre-breeding germplasm involving 1,000 exotic wheat accessions. Population panels are being maintained for germplasm selections, genetic analyses and genomics-assisted breeding. Preliminary evaluation of pre-breeding populations suggests that useful variations from landraces have been incorporated into the breeding germplasm pool and that these resources will contribute to varietal development and genetic analyses. Multi-environment evaluation of these gene bank-derived materials is now beginning with a growing network of partners in target environments, currently mainly in Mexico and South Asia. The genetic resources described herein are available to the global wheat community.