MODELLING THE TEMPERATUREMYCELIAL GROWTH RATE RELATIONSHIPS IN FUNGI RHIZOCTONIA spp
A. Alizadeh Mihan, M.A. Aghajani
Temperature is one of the most important factors affecting the fungal growth and development and their relationships have been investigated in physiological and epidemiological studies. Cardinal temperatures of fungi were obtained from these studies and they were mainly performed via visual estimation of polynomial modeling, which resulted in non-biologically meaningful parameters. In this study, eight nonlinear regression models were used for modeling temperature-mycelial growth rate relationships of three anastomosis groups of Rhizoctonia spp. (AG 1-IA, AG 4 and WAG-Z). Comparison and selection of the best-fitting model were conducted based on SE, adjusted R2, RMSE, a, and b, and they were then ranked by AIC statistic. The results indicated that the segmented model was the best fit for all three AGs. Based on AICc and i, the segmented model was the best fit model for describing growth rate of AG 4 and WAG-Z at different temperatures. In case of AG 1-IA, the cubic model could produce the least amount of AICc and the segmented model ranked second. Besides, i of dent-like model was <10 in all three cases and, therefore there was not a significant difference in fitness of these models. Estimated Tb and (Tc) of AG 1-IA, AG 4 and WAG-Z by the segmented model were 7.94, (38.69)°C, 7.66, (39.59)°C and 8.11, (41)°C, respectively. Optimum temperatures estimated by the segmented model for AG 1-IA, AG 4 and WAG-Z were 28.58°C, 29.99°C and 33.72°C, respectively.