Quantification of the effects of aging on cardinal temperatures of Echinops seed germination using nonlinear models (Echinops spp)

In order to determine the cardinal temperature of decayed sugarcane seeds, this study was carried out factorially in a completely randomized design with three replications in Khuzestan University of Agriculture and Natural Resources. The first factor was aging at 5 levels (0, 24, 48, 72 and 96 hours of decline) and germination temperatures at 7 levels (5, 10, 15, 20, 25, 30, 35 and 40 ° C). The results showed that the percentage and speed of germination were affected by the interaction of temperature in the decay so that their highest value was in the temperature range of 20 to 25 ° C and the decay in addition to reducing their amount increased the range of changes of this plant at different temperatures. The highest germination percentage was observed at 20 ° C in undeveloped seeds and 15 to 20 ° C at 24 and 48 h. Estimation of different non-linear models on germination rate also showed that among the evaluated models, the better toothed model was the model for germination of sugarcane seeds at different levels of decay. The germination basal temperature of sugarcane was estimated to be 1 ° C in non-degradable conditions, which increased to 1.8 ° C in 24 hours of decline and decreased again in higher degradations. The optimum germination temperature of this plant was between 20 to 32 at no aging conditions.