Plant & Animal Genomes XVII Conference

January 10-14, 2009
Town & Country Convention Center
San Diego, CA

Association Mapping In Maize To Improve Drought Tolerance

Tim L. Setter¹ , Jianbing Yan² , Marilyn Warburton² , Edward S. Buckler³ , Mark Sawkins² , Jean-Marcel Ribaut⁴ , Yunbi Xu² , Pichet Grudloyma⁵ , James Gethi⁶

¹  Dept. Crop & Soil Sci. and Plant Breeding & Gen., Cornell Univ., Ithaca, NY, 14853, USA

²  International Maize Improvement Center (CIMMYT), 06600 Mexico, D.F., Mexico

³  USDA-ARS and Cornell Univ., 159 Biotechnology Bldg., Ithaca, NY, 14853, USA

⁴  Generation Challenge Program c/o CIMMYT, 06600 Mexico D.F. Mexico

⁵  Nakhon Sawan Field Crops Research Center (NSFCRC),Takfa, Thailand

⁶  Kenya Agricultural Research Institute (KARI), Mtwapa, Kenya

To identify genes that confer tolerance to water deficit at the reproductive stage in maize, we have used an association mapping approach with SNPs identified in candidate genes for drought related traits. Phenotyping was conducted on more than 400 diverse tropical inbreds in Mexico-TL and on 350 hybrids at 5 locations; two years at each. Plants were subjected to water deficit at flowering. Lines were phenotyped for abscisic acid (ABA) and carbohydrate levels and for traits related to yield and performance in stress. More than 36 SNPs from 30 genes were significantly associated with yield, metabolite and field morphological traits. Several ABA metabolite traits were associated with ABA-related genes. Many transcription factors and regulatory proteins were among the significantly associated SNPs. SNP associations with flowering date were abundant. This project has added to our understanding of the genes related to drought response and identified strong candidate genes that can be used to develop markers or transformants for future improvement of drought tolerance.