Increasing the Rate of Genetic Gain in the CIMMYT Maize Program Using Doubled Haploids and Marker-Assisted Selection.

The CIMMYT Global Maize Program (GMP) is applying doubled haploid technology and marker-assisted breeding approaches both jointly and independently to increase the rate of genetic gain for biotic and abiotic stress tolerance in our breeding programs.  Key considerations regarding best practices for successful implementation of these technologies in applied breeding programs will be explored.  Emphasis will be on logistics planning, critical path analysis, decision tree flowcharts, and stakeholder engagement for optimizing the choice of method or combination of methods to maximize the cost effectiveness of the breeding programs.  A case study looking at the integrated application of these technologies to the GMP-Africa breeding programs will be presented.  The challenge of the GMP-Africa team is to combine multiple biotic stress tolerances, particularly Maize Streak Virus (MSV) and Maize Lethal Necrosis (MLN), together with appropriate abiotic stress tolerances, competitive yield under optimal conditions, and improved cost of goods sold (COGS) parameters.  The breeding team utilizes a combination of elite adapted and relatively unadapted donor germplasm (both temperate and tropical) to simultaneously improve genetic gain for each of these important traits.