Mapping Drought QTL in Tall Fescue Populations.

Tall fescue (Festuca arundinacea Schreb.) growth and persistence are adversely affected by the hot-dry summers in the Southern Great Plains. Both forage yield and drought tolerance are difficult to select for because of large genotype-by-environment interactions. The objective of this project was to construct mapping populations, phenotype in multiple locations, genotype, and carry our quantitative trait analysis to identify markers for marker-assisted selection. Two mapping populations were constructed based on sets of contrasting genotypes for drought stress. One population was established one year prior to the other. Both populations were planted in two Oklahoma locations and in the greenhouse. In addition, one population was planted at Logan, UT. In the first year, the population did not experience drought-stress due high rainfall. Data were collected on biomass production both in the field and greenhouse. Transgressive segregation for biomass yield was recorded. The mapping population is being genotyped with framework microsatellite and STS markers obtained from a tall fescue reference map. Candidate drought-associated markers were added to the map. Details of the genotyping and phenotyping will be presented.