Genotype X Environment Interactions in Turf Quality of Selected St. Augustinegrass Hybrids and Cultivars.

The ability to select and identify new St. Augustinegrass [Stenotapharum secundatum (Walt.) Kuntze] cultivars with broad environmental adaptation is restricted by genotype x environment interactions. Our objective was to identify breeding lines that show stability across the target use area. A group of 29 selected hybrids plus the cultivars ‘Floratam’, ‘Palmetto’, and ‘Captiva’ were evaluated at five geographically distinct locations in Florida (Jay, Hague, Citra, Vero Beach, and Arcadia) for three growing seasons from 2011 to 2014. Primary response variables were turf color and turf quality. Plots size was 1.6 x 1.6 m² with clean tilled borders maintained between plots. Fertility followed UF/IFAS homeowner recommendations and no fungicides were applied. Plots were mowed at 7.5 cm.  Plots were generally evaluated on a bi-monthly basis for turf quality. Data were analyzed using mixed modes in ASReml. Effects of genotypes, locations and genotype by location interactions were generally significant at most evaluation dates. Despite significant G x E interactions, several hybrids had turf quality and plot cover superior to the released cultivars at all locations. Among these superior hybrids were UFSA 11 and 15, and NUF 116, 129, 150, 252, 253 and 254. Sod grower trials of selected superior hybrids are planned for the 2015 season as we move toward identification of one or more superior hybrids for cultivar release with broad environmental adapatation.