Multienvironment evaluation of St. Augustinegrass breeding lines for turf performance via a mixed-models approach

Abstract

St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is a turfgrass extensively used in managed landscapes in Florida and throughout the southeastern United States. To develop cultivars with broad adaptation, it is necessary to understand the effect of genotype × environment interactions. The objective of this study was to estimate genetic parameters in St. Augustinegrass for coverage, turf quality (TQ), and turf color (TC) in a multienvironment trial across five locations in Florida (Arcadia, Hague, Citra, Cocoa Beach, and Jay) evaluated over 5 yr (2011–2016). The experiment consisted of 26 advanced breeding lines, and four cultivars: ‘Floraverde’, ‘SS-100’ (Palmetto®), ‘NUF-76’ (Captiva®), and ‘Floratam’. Trials were arranged as randomized complete block designs with three replications. Linear mixed models with repeated measures were implemented in ASReml-R. Significant differences were observed among genotypes. The estimates of genotype-mean broad-sense heritabilities ranged from 0.37 to 0.96 for coverage, 0.00 to 0.37 for TC, and 0.27 to 0.93 for TQ. Genotypic correlations ranged from 0.05 to 0.90 for coverage, 0.48 to 0.69 for TC, and 0.35 to 0.83 for TQ, indicating stable genotypic performance for TQ and TC between locations. For coverage, most genotypes clustered together, whereas greater genotypic variability was observed for TQ and TC. Genotypes ‘04-4-1-4-6’ and ‘FSA1602’ showed the best overall performance across the different traits analyzed for most locations and both genotypes are recommended for further use in future crosses in the breeding program. FSA1602 was recently released as FSA1602 and is being commercialized under the trademark CitraBlue®.