SALINITY EFFECTS ON BENTGRASS GERMINATION

Duplicate studies were conducted to determine salt tolerance during germination of eight bentgrass (Agrostis spp.) cultivars commonly used for overseeding warm-season turf species, such as bermudagrass (Cynodon spp.) putting surfaces. Bentgrass seeds were germinated on agar salinized with 0, 4000, 8000, 12,000, or 16,000 mg-liter-1, with the highest rate approaching one-half seawater salinity. Total germination decreased linearly or quadratically for specific cultivars as salinity increased. Time necessary to reach 50% germination across all salt concentrations was shortest for 'Highland' colonial (Agrostis tenuis Sibth) and 'Seaside' creeping (A. palustris Huds.) bentgrass (almost-equal-to 3.7 days); intermediate for 'Kingstown' velvet (A. canina L.) and 'Streaker' red top (A. alba L.) bentgrass (almost-equal-to 4.5 days); and longest for 'Penneagle' creeping, 'Penncross' creeping, 'Exeter' colonial, and 'Pennlinks' creeping bentgrass (almost-equal-to 5.3 days). Salt concentrations necessary to reduce germination to 90%, 75%, and 50% indicated that 'Streaker' red top and 'Seaside' creeping bentgrass were the most salt-tolerant cultivars. 'Kingstown' velvet, 'Exeter' colonial, and 'Highland' colonial bentgrass were intermediate, while 'Pennlinks', 'Penncross', and 'Penneagle' creeping bentgrass were the most salt-sensitive cultivars.