Spatial distribution of nematode genera in relation to host plants of Western Ghats, Tamil Nadu, India

Abstract

A survey of plant parasitic nematodes (PPN) abundance and diversity was conducted in foothills of Western Ghats at Coimbatore and Nilgiris districts in Tamil Nadu, India. Our study pointed to evaluate the PPN association with weeds, shrubs, and herbs including some agricultural crop cover both agro and forest ecosystems. Soil samples were collected around the rhizosphere of the plants and nematodes were isolated, counted under a microscope and identified by morphological characters. We collected 415 soil samples around the rhizosphere of 84 major plant families. Among 84 plant families, we found 13 PPN genera those generally responsible for cash crop yield loss. The genus Helicotylenchus spp., and Meloidogyne spp., were found frequent (226,136 samples) and rarely Hemicycliophora spp.,. The PPN diversity was measured by Shannon diversity index which showed that the diversity of PPN found higher in plant species those from the families Rosaceae (2.20) and Rubiaceae (2.13). We also recorded the PPN richness was dominated in four plant families. This result reveals that the PPN diversity and richness are positively correlated with host plant species diversity and altitude. Further, our study concludes that a wild plant in the forest ecosystem behaves like a reservoir of PPN.