Diversity of Root-knot Nematodes Associated with Tubers of Yam (Dioscorea spp.) Established Using Isozyme Analysis and Mitochondrial DNA-based Identi?cation

摘要

The root-knot nematodes (RKN), Meloidogyne spp., represent an important threat to yam (Dioscorea spp.) production in WestAfrica.WiththeaimtoestablishthediversityofRKNspeciesaffectingyamtubers,forcontrolandresistancescreeningpurposes, surveys were conducted in the main yam producing areas of Nigeria.Galled tubers (N = 48) were collected from farmers’ stores and markets inninestatesin Nigeriaandin onedistrict inGhana.RKNisolated from yamtubers were identi?ed usingenzyme phenotyping (esterase and malate dehydrogenase) and mitochondrial DNA (mtDNA) NADH dehydrogenase subunit 5 (Nad5) barcoding.Examination of48populations revealed thatyamtuberswereinfestedby Meloidogyne incognita(69%),followedby M.javanica(13%), M.enterolobii (2%), and M.arenaria (2%).Most of the tubers sampled (86%) were infected by a single species, and multiple species of RKN weredetectedin14%ofthesamples.Resultsofbothidenti?cationmethodsrevealedthesamespecies,con?rmingtheiraccuracyforthe identi?cation of these tropical RKN species.In addition to M.incognita, M.javanica, andM.enterolobii, we report for the ?rst timeM.arenaria infecting yam tubers in Nigeria.This ?nding extends the list of yam pests and calls for caution when developing practices for yam pest management.