Next-Generation Platforms for the Genetic Analysis of Complex Traits: Examples from Maize and Cotton

Dr. Michael Gore
USDA
Tuesday, February 5, 2013 - 4:00pm
Marley 230

Phenotypic variation of most agronomically important crop traits is under polygenic control, and understanding the genetic basis of phenotypic variation within and between populations is important for connecting genotype to phenotype. To that end, the largest public mapping resource of any species for evaluating the genetic architecture of complex traits was constructed in maize. The Nested Association Mapping (NAM) population of 5,000 recombinant inbred lines captures a wide range of allelic diversity and exploits the benefits of linkage analysis and association mapping to facilitate fine mapping of quantitative trait loci (QTL). In a large-scale effort with an overall goal of nutrient dense maize, we have conducted over 10,000 HPLC runs to quantify 14 carotenoid and 7 tocochromanol compounds in grain from the nested association mapping (NAM) population and investigated the genetic basis of these traits. In cotton, we have made significant progress towards the development of a tractor-based, high-throughput phenotyping (HTP) system for the simultaneous proximal remote sensing of canopy temperature, spectral reflectance, and geometry of field-grown plants. This system was used to phenotype a cotton genetic mapping population over the growing season and multiple times of day. Our results suggest that the HTP system can be potentially used as a tool for studying complex trait variation and selecting stress tolerant lines in breeding programs when combined with genotyping-by-sequencing approaches.