Multi-Environment Evaluation of St. Augustinegrass Genotypes Under Shade
Turfgrass, Selection Index , Multi-environment trials
St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] is an important warm-season turfgrass. It is cultivated in warm-humid to tropical climates, including the Southeastern United States, where shade represents an environmental limitation for turfgrass growth. The objective of this study was to select turfgrass cultivars with broad adaptation and resilience to shade stress. For that, we evaluated genetic parameters, genetic correlations, and direct and indirect selection gains in St. Augustinegrass genotypes for percent living ground cover (Coverage), turfgrass quality (TQ), and canopy height (HT) and dark green color index (DGCI) under induced light restriction. These traits were evaluated in 42 experimental genotypes, and two cultivars: ‘Raleigh’ and ‘Tamstar’, in three locations in the Southeastern United States (Citra - FL, Raleigh - NC and Tifton - GA), over three seasons (2016–2018). Trials were arranged as randomized complete block designs with two or three replications. Significant differences were observed among genotypes for Coverage and TQ in all locations. Coverage and TQ presented the greatest correlation values for all locations, while Citra and Raleigh were the most correlated locations for all traits. Indirect selection using Coverage as response variable generated the greatest selection gain on other traits.