Growth Characteristics and Physiological Stress Tolerance of Eight Bermudagrass Cultivars Intended for Athletic Fields and Golf Course Fairways.

Abstract

Bermudagrass (Cynodon [L.] Rich) is well suited for use as recreational turf in the southeastern United States. Cultivars included in the trial were, 'TifSport', 'Tifway', 'Tifton 10', 'Navy Blue', 'GN-1', 'Patriot', 'Celebration' and 'Quickstand'. During 2003 and 2004, data were collected on a wide range of criteria including, response to mowing height differential, nitrogen fertility rates, root and thatch production, surface hardness, rate of lateral spread, disease incidence, visual turf quality, wear tolerance, drought tolerance, and low temperature stress tolerance.

Under mowing heights of 1.25 and 1.90 cm in 2003, TifSport reflected the highest turf quality ratings at both heights of cut and mowing height had little effect on cultivars. Nitrogen fertility rates of 100, 150, and 200 kg N ha-1 had no effect on cultivars at any time during the study. In 2003, TifSport had the greatest root mass, while GN-1 and Navy Blue produced the greatest amount of thatch. Celebration had the least surface hardness during 2004. Rate of lateral spread data was gathered in 2004 by extracting cores from each plot and monitoring regrowth using digital images over a period of four weeks. Celebration achieved the greatest recovery at 86% by the fourth week, followed by TifSport and Quickstand, each with 70% recovery. In May 2004, Spring Dead Spot (Ophiosphaerella korrae) was observed on the field plots. Tifway had a greatest percent disease by area than did all other cultivars. Visual ratings over both years consistently ranked TifSport and Celebration higher due to their deep green color, fine texture, and high density. Traffic simulation had an effect on Quickstand, GN-1, Navy Blue, and Tifton 10. Navy Blue resisted leaf firing until the seventh week of the drought stress study; longer than any other cultivar. Low temperature stress tolerance testing was conducted using two methods, dormant field cores and excised stolons in February of 2003 and 2004. Field cores were potted and placed in a Low Temperature Stress Simulator (LTSS) at a temperature of either -1oC or -7oC for varying exposure lengths of 12, 24, 48, or 72 h, respectively. Patriot and Quickstand exhibited greater recovery rates than all other cultivars in the core study at -7oC. The stolon study was composed of a single 24 h exposure length with temperatures ranging from 3oC to -10oC. Results between the core and stolon studies show correlation (rs = 0.82 and a probability of 0.01) with 'Quickstand' and 'Navy Blue' being more cold tolerant than all other cultivars with the exception of 'Patriot'.