Resistance reaction of tomato genotypes (Lycopersicum spp.) to Rhizoctonia solani Kuhn

Abstract

The present study was undertaken with the following objectives: 1) to evaluate the level of pathogenicity of four Rhizoctonia solani isolates obtained from diseased tomato plants (RT), from eggplant (RB1 and RB2), and pepper (RP) and tested on 9 tomato genotypes grown in experimental plots; and 2) evaluate the resistance reaction of 73 tomato genotypes to the pathogen. Experiments were performed in greenhouse using sterilized soil. In experiment I, R. solani isolates from RT and RB2 plants were identically more pathogenic RB1 and RP. In experiment II, wide variability in the resistance reaction to R. solani (isolated from a tomato plant - RT) was observed among the 73 tomato genotypes (which included wild species, Brazilian varieties and introduced material), with percentage of plant survival ranging from 91% for the cultivar Quick Pick to 0% for the genotype LA-462. None of the materials tested showed immunity, but different levels of resistance were observed, ranging from susceptibility to high resistance, as expressed by the survival percentages.