Genetic Architecture Controlling Flowering Time Variation in Exotic Derived Doubled Haploid Maize Lines

Genome-wide association studies (GWAS) are a powerful tool utilizing linkage disequilibrium to aid in the dissection of complex traits, such as flowering time in maize (Zea mays L. subsp. mays).  To further increase the power of such a study, dense marker coverage is of great importance to ensure rare alleles of interest are identified within the chosen mapping population.  Herein, GWAS is used to investigate the genetic basis for the variation of flowering time in a diverse panel of 252 BC1 generation-derived doubled haploid lines, representing a total of 52 maize races represented by 54 different exotic maize accessions.  Recurrent parents were PHZ51 or PHB47, temperate maize inbred lines with expired Plant Variety Protection. Genotyping-by-sequencing methodology was used to obtain dense marker coverage across the genome.  The mapping panel was planted across multiple environments in the U.S. Corn Belt region in an alpha (0, 1) incomplete block design.  Four checks (PHZ51, PHB47, B73, and Mo17) were included and ~10% of the plots planted represented these checks.  Preliminary results to be presented will include associations between SNP markers with the flowering time traits: anthesis, silk, and anthesis-silking interval.