Isolation and Characterization of Nematodes from Soil and Root Samples of Tomato

Abstract

The present study selected and identified nematodes from soil and root samples of tomato (Solanum lycopersicum) from soil in the tomato field at Lapai, Niger State, Nigeria. Five tomato fields with two tomato varieties (Roma VF and Ife-1) were sampled using the stratified random sampling technique to obtain soil and root samples. Baermann funnel method was used for soil samples and modified centrifugal flotation method for root samples to extract nematodes, which were identified according to their morphological features observed under a compound microscope, and morphological measurements were used for confirmation of the taxonomic classification. Four of the five taxa of nematodes identified belonged to genera (Meloidogyne spp., Heterodera spp., Pratylenchus spp., and Xiphinema spp.), while the fifth was identified to species (Rotylenchulus reniformis). Population density of nematodes did not differ between soil and root samples, however root samples containing 135 ± 8 nematodes/g of root (n = 50) had significantly higher numbers of nematodes than soil samples (75 ± 5 nematodes/g of soil, n = 100; Welch's t(68.7) = 48.51; p < 0.001). The most common taxon in both habitats was Meloidogyne spp. and it was not significantly different between the two tomato varieties. Key contributions from morphological measurements were in species identification and classification. The results of this study indicate the importance of plant parasitic nematodes in tomato production and their ecological function in soil-root interactions and the need for integrated nematode management in the study area.