Determine the cardinal temperatures of seed germination in Chrysanthemum maximum Ramond

In order to estimate the germination cardinal temperatures, a laboratory experiment was conducted with Chrysanthemum maximum Ramond in a completely randomized design with four replications. Various constant temperatures (5, 10, 15, 20, 25, 30 and 35ºC) were considered. Germinated seeds were counted each day and the rate of germination and germination percentage was calculated. Cardinal temperatures diagram of Chrysanthemum maximum Ramond seed germination was constructed based on two regression models including segmented model and beta model. The effects of temperatures on rate and percentage of germination were significant. The highest germination rate was in 20º, R50=0.067 (Reverse time to 50% germination). Based on the two regression models, Intersected-lines Model and Quadratic Polynomial Model, the cardinal temperatures of Chrysanthemum maximum Ramond seeds germination (Tbase, Topt and Tmax) were: (1 - 3), (19– 23.1) and (43 – 59) °C, respectively. With increasing temperature, the more suitable conditions in terms of temperature, is created for Chrysanthemum maximum Ramond germination and germination rate is increased