[The effect of Interaction Between Potato virus Y and Cucumber mosaic virus on Tomato Plants]

The experiment carried out in 2012 in a greenhouse in Tartus. And studied the effect of single and mixed infection of Potato Y Virus (PVY) and Cucumber mosaic virus (CMV) on tomato plants ( cv. Elegro and Local), was studied. Results shows that the antagonistic relationship between two viruses was existing on symptoms in two variety in treatment with two viruses at the same time .The interactions in both variety to virus infections were different in mixed infections and their effects were the least on number of leaves(Elegro 106.42, Local94.42), number of branches (Elegro16.75, Local 15.87), height plant (Elegro 103.58 cm, Local87.17 cm), stem circumference of stem tomato plants (Elegro 4.84 cm, Local 4.59 cm), number of clusters per plant (Elegro 5.5, Local4.25), number of flowers (Elegro 4.57, Local 4.1), number of fruit (Elegro 5.5, Local 2.72, percentage of fruiting per plant (Elegro 65.68%, Local 65.68%), fruit diameter per plant(Elegro 4.8 cm, Local 3.64 cm), weight per plant(Elegro 1.94 kg, Local 0.96 kg) , weight fresh plant (Elegro 1.77 kg, Local 0.8 kg) and root weight (Elegro 0.22 kg, Local 0.104 kg). which was probably due to the antagonistic relationship between Potato Y virus and Cucumber mosaic virus, Whereas neither single nor mixed infection, caused a significant difference in percentage of fruit setting per plant. When the plants were first inoculated with Cucumber Mosaic Virus and later after 15 days with Potato Y Virus, the effect of Cucumber Mosaic Virus was prominent. On the other hand, first inoculation with PVY suppressed the effect of the subsequent infection with CMV. Consequently, the timing of mixed infection had a role in appearance, development and effect the another virus. When the interactions was studied between variety and the way of infection, there 65 was the least effect in treatment with two viruses at the same time. There was prominent deferment's between the variety Elegro and Local.