Interaction between the root-knot nematode, Meloidogyne javanica and the crown gall bacterium, Rhizobium vitis , in three almond rootstocks *

Incidence of the root-knot nematode, Meloidogyne javanica and the crown gall bacterium, Rhizobium vitis , are increasing in different regions of Iran. In order to evaluate the response of different almond rootstocks to interaction of the root-knot nematode and the crown gall bacterium, three rootstocks viz . GN15, GF677 and Hybrid of peachShoorabi almond, inoculated with M. javanica and R. vitis in a factorial experiment with completely randomized design under greenhouse condition. Almond rootstocks were transferred to the main pots, and then the pots were inoculated by 9000 eggs and second stage juveniles of the nematode per pot. Three weeks after inoculation, the rootstocks were inoculated with a suspension of 10 8 of bacterial cells at the rate of 1% (V/W). Three month after the last inoculation, the growth indices of plant and nematode as well as pathogenicity indices of the bacterium were measured. The results showed that except GN15, other rootstocks were susceptible to nematode. The rootstock GN15 was susceptible to R. vitis . As a result, nematode infection predisposed GN15 to bacterial infection, but bacterial infection had no effect on nematode indices.