Effects of Temperature on Germination of Eleven Festuca Cultivars

摘要

Many studies have shown that water potential at planting affects the germinationrate and final germination of Festuca cultivars. Limited information is available about the extent of variability in temperature-dependence of germination among different Festuca cultivars. Our objective was to study germination at five temperatures for a wide range of Festuca cultivars. Festuca seeds were screened for germination during 28 days in polyethylene growth pouches held at constant temperatures of 10, 15, 20, 25, or 300C. The germination percentage significantly (p < 0.05) increased as the temperature increased from 10 to 150C, when averaged across the cultivars, and decreased thereafter. The cultivar Clemfine tall fescue (Festuca arundinacen Schreb.) had the greatest germination percentage, and Arctared red fescue (Festuca rubra L.) had the least when averaged across the five temperatures. Conversely, the average time to germination (Atg) was greatest at 100C and least at 300C. Reaching a germination level of 80% or more of the seeds required 14 days at 100C, 9 d at 150C, 8 d at 200C, and 7 d at 25 or 300C. Base temperatures required for germination of Festuca species were 3.20C for rapid germinators, 3.6 to 60C for medium germinators, and 4 to 60C for poor germinators. Heat units (growing degree-days >100C) calculated for the rapid germinators were 1290C-d, 120 to 1400C-d for medium germinators, and 135 to 1910C-d for the poor germinators. Germination decreased as heat units were increased. The Atg and heat unit regressions explained.