Seashore paspalum (Paspalum vaginatum Sw.) performance under shade in multi-environment trials

Abstract

Shade caused by trees or buildings can affect the quality and growth of turfgrasses. Thus, breeding for shade tolerance is an essential component of most turfgrass improvement programs. The objective of this study was to evaluate the performance of seashore paspalum (Paspalum vaginatum Sw.) breeding lines under shade in multi-environment trials. Germplasm sources were 20 lines from the University of Georgia seashore paspalum breeding program and two checks, the cultivars SeaDwarf and SeaStar . Field trials were conducted from 2016 to 2019 under shade structures designed to reduce ambient sunlight at three locations: Citra (FL), Tifton (GA), and Raleigh (NC). The response variables evaluated were percent living ground cover (%GC), dark green color index (DGCI), canopy height (CH) and turfgrass quality (TQ). Data were analyzed by mixed model approaches using ASReml-R, and the t-statistics were used to group the entries. Significant genetic variances were observed in the single-location-repeated-measures analysis for CH and DGCI at Citra and Tifton, %GC at Citra, and TQ at Raleigh. Spearman correlations of the predicted values for entries between locations ranged from low to moderate, with the exception of between Citra and Tifton (0.76) for CH. There were a few breeding lines with superior performance to the entry average for all traits for which the entry variance was significant. In conclusion, genetic variability was observed for all traits and superior seashore paspalum breeding lines for multiple traits were identified under shade.