SPECIES IDENTIFICATION OF ROOT KNOT NEMATODES IN PAKISTAN BY RANDOM AMPLIFIED POLYMORPHIC DNA (RAPD-PCR)

DNA extracted from females or juveniles of Meloidogyne incognita, M. arenaria and M. javanica were used for species identification at the James Hutton Institute (JHI), Dundee, Scotland. The randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) was used to investigate the genetic diversity among the Meloidogyne species populations. Nematode populations of the same species were grouped unambiguously by most of the polymorhpic RAPD pattern with any of the three RAPD primers viz., SC10-30, OPG-13 and OPG-19. The total numbers of amplified polymorphic DNA fragments obtained were 97, 342 and 48 for M. incognita, M. javanica and M. arenaria, respectively. These distinctive RAPD fragments were candidates for intraspecific and intrapopulation identifications. Variation among populations of each species was also observed, especially within M. javanica. The three primers produced consistent patterns and yielded species-specific fragments that enabled the differentiation among the three Pakistani Meloidogyne species and four RKN species (M. chitwoodi, M. fallax, M. hapla and M. entrolobii (Syn =M. mayaguensis) from the JHI collection which were utilised as positive control.