Impact of tomato resistant rootstock on the root-knot and soil free-living nematodes dynamics and community composition

The impact of tomato resistant rootstock Beaufort(Lycopersicon lycopersicum×L. hirsutum) on root-knot nematodes and free-living nematodes in soil was studied under green house conditions. A two-way ANOVA (treatment×date) analysis on the density of the second stage juvenile root-knot nematodes (J2) indicates highly significant differences between sampling dates; and J2 in resistant rootstock plots significantly lower than in control plots. Free-living soil nematodes are classified into four trophic groups: bacterivores, fungivores, plant parasites and omnivores/predators, based on their nutrition resources. Significant differences are observed in fungivores and plant parasites among sampling dates; and the tomato resistant rootstock decreases the density of fungivores but increases the density of the bacterivorous nematodes. Ecological indices of fungivore/bacterivore ratio (F/B), fungivore/“bacterivore+fungivore”ratio (modified F/B), diversity, richness, evenness and dominance are compared between the treatment and control plots. F/B, modified F/B, richness and evenness show significant inconsistencies among sample dates, but more sensitive than other ecological indices used in the assessment of the impact of the tomato resistant rootstock on nematode community structure.