Reaction of some melon cultivars to charcoal rot Macrophomina phaseolina in Varamin

Charcoal rot Macrophomina phaseolina is one of the most serious soil brone disease of melon with economic importance throughout the world. Due to the failure of crop rotation, clean seeds and chemical control, application of the resistance cultivars and varieties, regarding to their ability in infestation reduction and less tissue destruction would be efficient. This study was to study the reaction of 22 different varieties of melon in Varamin area, as one of the main source of melon production in Iran, under the greenhouse condition. The experiment was taken place with four replications under complete random block design. Feature examined were wet weight, dry weight and pathogenicity index which were monitored in one month. Results of the pathogenicity indices showed than four varities, Honey Dave, Tashkand, Isafahan and Hybrid Ananas T with the lowest infestation index (1-2.1) were recognized as resistant and three varieties of Haj Mashallahi, Samsouri Isfahan, Ananas Mina MN1 with the highest pathogenicity index (>4) were recognized as susceptible. The results of wet weight mean showed that both hajmashallahi and 7065 MA hybrid has the lowest (17.05 gr) and Ananas T Hybrid showed the highest (57.05 gr); for dry weight, Honey Pack hybrid has the highest (7.16 gr) and Daregaz Mashhad showed the lowest (1.99 gr) weight. The results revealed a highly significant difference among the cultuvars which would be a clue to use plant resistance as a key factor in melon charcoal rot management.