A Modified Thermal Time Model to Predict Germination Rate of Ryegrass and Tall Fescue at Constant Temperatures

摘要: The thermal time model is widely used to describe the relationship between germina- tion and temperature. However, breaks germination curve into two parts ignores possibility that rate constant at optimal temperatures. pur- poses of this study were investigate rela- tionship temperature within context optimum tempera- ture (T o ) may be better defined as a range rather than single point test for variation in minimum b given subpopulation g subopti- mal temperatures (q 1 (g)) among subpopulations. Seeds ryegrass cultivars, perennial rye- grass (Lolium perenne L.) 'Bronsyn' annual multiflorum Lam.) 'Archie', tall fescue cultivars (Festuca arundinacea Schreb.) 'Flecha AR542' 'Advance' germinated ranging from 6 43°C 3°C intervals monitored variability 10th 80th percentiles. Linear regres- sion was estimate parameters modified suboptimal, optimal, supraoptimal all exhibited an T over which constant, although magnitude depended on cultivar and/or species Therefore, incorporating upper limit opti- mum ou lower ol proposed. This can predict some circumstances.