ARS | Publication request: Consistency of Qtl for Dollar Spot Resistance Between Greenhouse and Field Inoculations, Multiple Locations, and Different Population Sizes in Creeping Bentgrass

Submitted to: Molecular Breeding of Forage and Turf Conference
Publication Type: Abstract
Publication Acceptance Date: March 1, 2005
Publication Date: N/A

Technical Abstract: Dollar spot caused by Sclerotinia homoeocarpa F. T. Bennett is the most economically important turf disease in North America. Dollar spot resistance in a creeping bentgrass cultivar would greatly reduce the cost and environmental impacts of fungicide application. To understand the effect of population size, inoculation assays, and field locations on QTL for dollar spot resistance in creeping bentgrass, a full-sib genetic mapping population consisting of 697 progeny was developed from a cross between the outcrossing clones named 372 and 549. A dense linkage map with fourteen linkage groups has been constructed, covering 1144 cM with 227 RFLPs, 177 RAPDs, and 73 AFLPs. Ninety-three of the RFLP markers are from sequenced probes from cDNA libraries, constructed from leaf tissue of the two mapping parents. Number, location, and effect of QTL for dollar spot resistance were compared between greenhouse and field inoculations, two locations in WI, WI and MI locations, and between experiments as well as over several ratings within the same location. One major QTL on linkage group 7 is consistent over multiple ratings as the disease progressed and also across locations and experiments. Greenhouse inoculation, rating methods, and field location-specific QTL with minor effect were also detected on various linkage groups. Effect of population size (94-697) on the significance of the QTLs was also examined. Markers tightly linked to the QTL which are stable under environmental factors are critical for the success of MAS in future dollar spot resistant creeping bentgrass-breeding programs.