Genetic structure and diversity within local populations of Meloidogyne (Nematoda : Meloidogynidae)

A survey of Meloidogyne in La Vera (Spain) was carried out during October 1 995 and 1997. Isozyme electrophoresis (A-EST, MDH, CAT, GPI, DIA, GOT and S OD) was performed for each nematode isolate, each of which was cultured fro m an egg mass. In 1995 seven isolates of M. incognita, two of M. javanica a nd 75 of M. arenaria were found, while in 1997 one isolate of M. javanica a nd 72 of M. arenaria were found. Taxonomic relationships were established a mong 151 isolates using enzyme phenotypes by means of Multiple Corresponden ce and UPGM analysis. Twenty-six Multilocus Enzyme Electrophoresis (MLEE) p henotype variants were detected in ten significant taxonomic units: M. aren aria (seven units), M. incognita (two) and M. javanica (one). A total of 13 loci were identified and allelic frequencies for MLEE phenotype variants w ere estimated. Genetic distances among them suggested that M. arenaria is a poly- or paraphyletic group formed by at least two or three monophyletic l ines of different origins. The evolutionary and epidemiological implication s are discussed.