Searching about Resistance of Common Cultivated Varieties in Varamin to Separated Fungal Phytophthora drechsleri from the Same Place

Dieback plant disease caused by fungi species Phytophthora is one of the most important soil borne disease in Iran. During studies in Varamin, one of the most harmful factors on crops is Phtophtora species in that place. So that in almost all different villages of this city, limitation of cultivation of crops such as cantaloupe, that is one of the most important product in this region, has arisen. This study had been done for searching about reaction of common cultivars in some plants in Varamin to the separated Phtophthora drechsleri from the same place by measuring plant growth factors. Seeds of melon in Ivanaki cultivar, cantaloupe in Samsoori cultivar, tomato in Urbana cultivar, red bean in Mahalli cultivar, were planted in pots containing sterile soil, then mentioned fungal were infected by Zoospore suspension and kept in greenhouse condition. In addition, the reaction of safflower seedlings of species Phytpophthora melonis was used to differentiate species. Percentage of disease as well as growth factors such as stem fresh and dry weight, stem length and root length during the time of 1, 2 and 3 weeks after inoculation had been measured. Symptoms in different hosts were seen such as reducing growth, root, and crown rot, yellowing and wilting of aerial organ and ultimately these symptoms led to death in susceptible hosts and destroyed them. Due to the discussed factors, cantaloupe and, melons were very sensitive hosts, tomatoes were sensitive hosts and beans were relatively resistant hosts, the results indicated sensitivity of used cultivars to the phytophthora in this area. Also in checking the germination percentage of seeds, separated Phtophthora drechsleri could affect the germination of melon and cantaloupe seeds, their germination percentage is drastically reducing. In a parallel study, the same research had been done to measure the effect of biofertilizers Trichodermin B and Subtilin for Phtophthora drechsleri control in mentioned cultivars, the results indicated positive effects of these two biofertilizers in pathogenic phytophthora control.