Study of interaction between salinity and charcoal rot diseases of melon (Macrophomina phaseolina) in Semnan and Garmsar

Charcoal rot diseases of melon caused by Macrophomina phaseolina is one of the most important diseases of melon occurring in regions with variable climate. Reduction of yield of melon by this disease has been reported up to 100% in some of Garmsar field. Salinity which can cause the important trouble in plant metabolism and nutrition is present in Semnan and Garmsar areas. Melon is susceptible to salinity stress, therefore salinity stress may increase the susceptibility of melon to M. phaseolina. Different levels of salinity including, 0, 10, 25, 50 and 75 Mmol NaCl/l with and without fungal pathogen on two current cultivars of melon (Ivaneki and Susski) were investigated at the field conditions in Semnan and Garmsar areas. A factorial analysis for completely randomized design was used in these experiments with three replications. At all experiments, significant differences were observed among the different levels of any factors investigated including, cultivars, salinity and fungal pathogen presence. Interactions between investigated factors were significant too. The factors investigated in these experiments, clearly suggested the occurrence of a wide effect of salinity stress on charcoal rot development on melon cultivars and showed the importance of salinity management for decrease of disease severity.