ARS | Publication request: Mapping Drought QTL in Tall Fescue Populations

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 30, 2009
Publication Date: June 30, 2009
Citation: Kirigwi, F.M., Hopkins, A.A., Waldron, B.L., Saha, M.C. 2009. Mapping Drought QTL in Tall Fescue Populations. Meeting Abstract.

Technical Abstract: Tall fescue [Lolium arundinacetum (Schreb.) Darbysh.] growth and persistence are adversely affected by the hot-dry summers in the Southern Great Plains (Hopkins, 2005). 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. A mapping population was constructed based on a set of contrasting genotypes (B400 x W279) for drought stress. The population was planted in two Ardmore, Oklahoma locations and in the greenhouse. In addition, the population was planted at Logan, Utah. To date, data have been collected on relative water content (RWC), cell sap osmotic potential (OP), canopy temperature, senescence, and aboveground shoot production in Ardmore and Utah Locations. Significant variation (P<0.0001) for genotypes was found for all traits tested. The population varied substantially for RWC in Ardmore (41.5 to 65.1%, mean 55.1%) and in Logan (32.6 to 86.2%, mean 53.9%). Increased RWC under water deficit is associated with increased drought tolerance (Elmi and West, 1995). The mapping populations are undergoing genotyping with framework microsatellite and STS markers obtained from a tall fescue reference map. In addition, candidate drought-associated markers have been identified and are being incorporated in the genotyping. Single marker analysis indicated that NFFS155, NFFG423 and NFFG106 were associated with shoot dry weight under drought stress both in Utah and Ardmore with R-squares of 0.32, 0.22 and 0.22, respectively. Additional details on data collection, genotyping and marker analysis will be presented.