Effect of pH variation on growth, sporulation and chlamydospore formation of four sp. of fusriam

The pH of modified Asthana and Hawker's medium ‘A’ was varied from 2.0 to 11.0 for view the effect of pH on growth, sporulation and clamydospore formation of Fusarium acuminatum, F. oxysporum, F. equiseti and F. solani. It was found that all the four Fusarium sp. could grow and sporulate over a wide range. The organisms failed to grow at lower pH viz., 2.0. the maximum dry weight of F. acuminatum, F. oxysporum, and F. equiseti were attend at pH 5.5 significant good growth of all the four Fusarium sp. was observed on the acidic side. Sporulation of the Fusarium sp. was excellent from pH 5.0 to 6.0 while it was absent at pH 2.5 but sporulation of F. equiseti was excellent from pH 5.0 to 6.5. Chlamydospore of F. acuminatum was observed at pH value between 3.0 to 10.5, in F.oxysporum and F. solani they appeared between pH 2.5 to 11.0, but in F. equiseti chlamydospore appeared between pH 4.0 to 11.0, no chlamydospores were observed at pH 5.5 in all the four Fusarium sp., change was observed in the final pH of the media. It was found that in all those cases where the original pH was low the final pH increased but in those cases where it was high the pH decreased. Optimum growth and excellent sporulation of all four organisms were observed at pH 5.5.