Quantitative Trait Loci Associated with Delayed Heat-Induced Senescence in Creeping Bentgrass.

Creeping bentgrass (Agostis stolonifera) is a cool-season turfgrass species widely used on high value turf areas. During summer months elevated temperatures cause significant decline in turf quality caused by premature senescence which is typified by a reduction in plant growth, a thinning and yellow of the canopy and eventual plant death. At present these is a great desire to develop new bentgrass cultivars with improved abiotic stress tolerances which can withstand heat stress conditions associated with the summer months. Unfortunately, heat tolerance, like many abiotic stress tolerances, is a complex multigenic trait. The identification of quantitative trait loci (QTL) allows for traits to be associated with specific regions of an organism’s genome by using molecular markers. Markers which are then significantly linked to a trait of interest can potentially be used for marker assisted selection to improve selection speed and efficiency in the development of improved cultivars. A creeping bentgrass mapping population was screened in several environments including greenhouse, growth chamber, and field conditions for important physiological traits associated with heat tolerance. These traits include overall plant performance, membrane stability, chlorophyll content, canopy temperature depression, and normalized difference vegetation index. A total of 33 QTL regions on 11 linkage groups were found for traits associated with heat tolerance. The identification of QTLs and associated markers corresponding with these traits will allow for the future development of bentgrass lines with delayed heat-induced senescence.