Quantitative trait loci associated with drought tolerance in creeping bentgrass

Improvement in the drought tolerance of the cool-season perennial grass species creeping bentgrass (Agrostis stolonifera L.) has significant value within the turfgrass industry. Understanding genomic regions associated with quantitative trait loci (QTL) such as drought tolerance will allow for advancement of breeding strategies to identify creeping bentgrass germplasm with improved abiotic stress tolerance. A multiyear and multienvironment study was performed to identify QTL in a mapping population of creeping bentgrass segregating for phenotypic traits associated with drought tolerance. Phenotypic data was collected during two growth chamber studies and 2 yr of a field trial. The phenotypic traits that were measured included turf quality (TQ), relative water content (RWC), canopy temperature depression (CTD), osmotic adjustment (OA), electrolyte leakage (EL), chlorophyll content (CHL), water use efficiency (WUE), and the normalized difference vegetative index (NDVI). Quantitative trait loci were identified for all traits on both parental maps except for OA and E.L. Quantitative trait loci were found within all linkage groups except for group 2 in both parents. The linkage group areas that had QTL with a significant amount of overlapping for multiple traits and trials included linkage group 5.2, 7.1, and 7.2 on the drought tolerant parent 'L-93' and groups 4.2 and 7.2 on the drought sensitive parent 7418-3. These and other QTL identified in this study have potential to be used in future studies that aim to more closely identify the genes associated with these QTL areas and for further investigation of their potential for use in marker-assisted selection practices.