effect of temperature on mycelial growth and resistant form of the some important phyto-pathogenic fungi

abstract temperature is one of the most important environmental factors affecting on physiological characteristics of fungi. in order to wide host range of macrophomina phaseolina (tassi) goildanich, verticillium dahliae kleb. and sclerotinia sclerotiorum (lib.) de bary, become aware from growth rate and productivity of resistant and survival form of these phyto-pathogens in different temperatures is necessary. in this order, present research was carried out with aim survey on effect of temperature on mycelial growth and resistant-form production of some isolates of m. phaseolina, verticillium dahliae and sclerotinia sclerotiorum on pda medium in laboratory conditions as rc design. in this experiment, various temperature treatments including 10±1, 15±1, 20±1, 22±1, 25±1, 27±1, 30±1, 35±1 and 40±1°c were used. the results showed that effect of the temperatures on growth and resistant-form production of the fungal isolates were significant at levels 5% & 1% by duncan multiple rang test. the results showed the highest mycelial growth and microsclerotia production at 30 and 35°c of other temperatures. the best temperatures for the mycelial growth and sclerotia production of s. sclerotiorum were estimated 25 and 20°c respectively. the results of the effect of the temperatures on v. dahliae isolates were different. the optimum growth-temperature for the isolates isolated from olive and almond were calculated 20°c, while optimum growth-temperature and microsclerotia-production for the isolates cotton were calculated 25 and 27°c. it is seem to the growth ability, resistant-form production and survival ability in wide range of the temperatures become one of the most important agents in ecological distribution, pathogenesis and ,finally, wide host range of these pathogens.