Identification of Quantitative Trait Loci for Drought Tolerance Characteristics of Creeping Bentgrass.

Loss of turf quality due to limited water availability is a major concern in turfgrass management. Therefore, there is an urgent need to develop turfgrasses that are able to provide high quality turf with limited irrigation. Several different drought tolerance mechanisms have been identified that are utilized by turfgrasses but have yet to be fully genetically characterized. It is known that most are known to be controlled by multiple genes or quantitative traits; thus, identification of quantitative trait loci (QTLs) associated with drought tolerance would improve the selection efficiency of drought-tolerant germplasm and varieties. The objectives of this study were 1) to evaluate genetic variations in drought tolerance of a mapping population of bentgrass; and 2) identify QTL markers associated with drought tolerance in creeping bentgrass. The mapping population with both parents (‘L-93’ and 7418-3) and 102 F₂ progenies exhibited significant variation in drought symptom expression when exposed to drought stress under greenhouse and field conditions. QTL analysis was conducted on the phenotypic traits associated with drought tolerance (turf quality, electrolyte leakage, relative water content, water use efficiency, leaf area index, green leaf biomass, and osmotic adjustment). QTLs consistent in both years of the study will be discussed.  The results indicate that some QTL markers associated with drought tolerance could be useful in marker-assisted selection of drought-tolerant turfgrass.