ORIGINAL ARTICLE

Growth dynamics of Fusarium pathogens causing head blight and Cochliobolus sativus causing spot blotch and common root rot under diverse pH values 

Fusarium head blight (FHB) caused by several Fusarium pathogens, spot blotch (SB) and common root rot (CRR) caused by Cochliobolus sativus are well-studied diseases of wheat and barley, leading to significant yield and quality losses globally. One study has analyzed the growth dynamics of one FHB species; however, no reports are available concerning SB and CRR diseases. To end this, the effect of diverse pH values on the mycelial growth of 16 FHB isolates of four pathogens (F. culmorum, F. verticillioides, F. solani and F. equiseti) and 54 C. sativus cultures (32 SB isolates + 22 CRR isolates) was investigated under in vitro conditions. The daily measurement findings of the mycelial growth zone in the control and fungal pathogen treatments were adjusted to the logistic model and Gompzert model to characterize the development of mycelium for each isolate under the same conditions. In the medium containing growing values of pH, FHB, SB and CRR pathogens grew at slower rates, inversely proportional to the value level. Logistic model and Gompzert model exhibited mean variance more than 97%, and the Gompzert model found to be more applicable because of better fit to the experimental data. Therefore, this model was selected to evaluate the impacts of the diverse pH concentrations on the kinetic parameters of FHB, SB and CRR fungal growth. Wide diversity among Fusarium and Cochliobolus isolates was detected, yet such differences did not distinguish among the five tested fungal species. To our best knowledge, this is the first report showing the significance of the Gompertz model to analyze the growth dynamics of several Fusarium and Cochliobolus pathogens under changeable pH conditions.