Controlled environmental conditions on germination of bermudagrass seeds

Abstract

Cynodon dactylon (L.) Pers., widely known as bermudagrass, is a cosmopolitan species used to form lawns, what provides aesthetic effects in parks and gardens, but also composes pastures and sports fields, such as golf and football. The use of seeds for the formation of new lawns is a common practice in Europe and in the United States, and is currently considerably expanding also in Brazil. It is important to understand the ideal environmental conditions for seed germination of each species, or cultivar. The aim of this study was to evaluate effects of salinity, temperature, light, substrate water contents, and sowing methods on germination of two bermudagrass cultivars: Princess 77 and Riviera. Three experiments, arranged in factorial schemes, were conducted: Experiment 1. Five salt concentrations (0, 25, 50, 75, and 100 mM) x two salt sources [sodium chloride (NaCl) and potassium chloride (KCl)]; Experiment 2. Three temperatures (constant at 30°C, alternating at 20 to 30°C, and alternating at 20 to 35°C) x presence or absence of light (8 h of light and 16 h of darkness, and total darkness); and Experiment 3. Four substrate water contents (25, 50, 75 and 100% of the substrate water retention capacity) x two sowing methods (in sand, and on sand surface). Germination percentage and germination rate were evaluated. Germination of Princess 77 was more effective in the absence of NaCl and KCl; at 20 to 35°C, either in the light or darkness; and at around 50% of the substrate water retention capacity, sown either in sand or on sand surface. Germination of Riviera seeds was more effective in the absence of NaCl and presence of KCl; at 20 to 35°C, in the light; and at 100% of the substrate water retention capacity, sown on sand surface. Key words: Poaceae, Cynodon dactylon, Princess 77, Riviera, salinity, temperature, light, substrate water content, sowing method.