Screening and histological characterization of guava (Psidium guajava L.) cultivars against root knot nematode, Meloidogyne enterolobii

Abstract

Surveys were carried out in major guava growing districts of Tamil Nadu in India for incidence of guava root knot nematode, Meloidogyne enterolobii. Fifteen cultivars viz., Alahabad Safeda, Lucknow-46, Thailand Red, Banaras,Lucknow-49,Mini Guava, Local, Beetroot Guava,Trichy-1,Hisar Lalit, Taiwan Guava, Chitidar, White seedless, Red seedless, and Panneer guava were collected from various nurseries and farmer fields for screening. The screening results showed that Mini Guava(4.0), Local(4.0), White seedless(3.6), Red seedless(3.6), Panneer guava(3.6) were susceptible to M. enterolobii, based on gall index while other cultivars were highly susceptible. Root exudate was collected from 15 cultivars and tested the hatching ability of eggs and second stage juvenile (J,s) mortality rate. The root exudate increased the egg hatching ability and decrease the juvenile mortality rate. The increase in hatching ability and decrease in mortality rate were directly proportional to time and concentration. Moreover, the histopathological response of M. enterolobii infested roots showed complete damage of the epidermis, cortex, endodermis, pericycle, xylem and phloem cells of roots and different stages of M.enterolobii were exist in clusters.