Molecular characterization of root knot nematodes (Meloidogyne spp.) infesting vegetable crops in Tamil Nadu

Abstract

A random survey was carried out in 56 locations in 28 districts of Tamil Nadu on eight different vegetable crops for root knot nematode which revealed four major species viz., Meloidogyne incognita, M. arenaria, M. javanica and M. hapla. M. incognita was recorded in all the locations in seven vegetable crops viz., tomato, brinjal, bitter gourd, ribbed gourd, bottle gourd and carrot with cent per cent frequency and a mean root knot index (RKI) of 3.89. The gourds were found to be the most favoured hosts with a RKI of 5.0. M. arenaria was encountered only on chilli in eleven locations with lowest RKI of 2.0. M. javanica was found in one location in Coimbatore with RKI of 5.0. M. hapla was observed only on carrot grown in the Nilgris (temperate region). For preliminary identification morphological and biochemical characterization was done. Further confirmation molecular characterization was done with the species specific SCAR primers with the help of PCR (Polymerase Chain Reaction) technique. This outcome holds significance for the management of root-knot nematodes infestation in Tamil Nadu.