REACTION OF GREEN LEAF LETTUCE GENOTYPES TO THREE SPECIES OF ROOT-KNOT NEMATODES ACCORDING TO TWO EVALUATION METHODS

Abstract

This experiment employed two evaluation methods to determine the reaction of green-leaf lettuce genotypes to Meloidogyne enterolobii, M. javanica, and M. incognita. Two hundred second-stage juveniles (J2) of each nematode species were separately inoculated on eight green leaf lettuce inbred lines developed by UNESP/FCAV. The cultivar ‘Vanda’ was also evaluated, as well as tomato cultivar ‘Santa Cruz Kada’ to aid in detecting a pattern of susceptibility. The host-plant reactions to the nematodes were determined by the root gall index (GI), egg mass index (EMI) and reproduction factor (RF). Treatments were arranged in a completely randomized design, in factorial 3 x 9 with seven replications. The results changed according to the method. The inbred line L₁ was moderately resistant to all the nematodes based on GI. However, all the genotypes were considered susceptible to root-knot nematodes considering RF reaction.