Intraspecific variation and host specificity of Iranian Populations of Pratylenchus vulnus

Morphometrical variance and host preference of two isolates of root-lesion nematode Pratylenchus vulnus, extracted from apple and maple trees, were analysed. Studies of morphometric characters (population cultured on carrot disks) with MVSP-32 software (UPGMA method and euclidean similarity coefficient) and also analysis of variance showed that number of variable characters is higher among the female nematodes than the male ones. Characters were grouped into three categories (high variability; higher than 70%, medium variability; between 50% to 70% and low variability; less than 50%) according to a percentage of inter-population variance. In the female nematodes, head-vulva distance and overlapping amount indicated the least variability in the two isolates. However, Body Width and Anal Body Width were the most variability. Host preference of maple (Acer velutium and Acer cappadocicum), olive (Olea sp.), corn (Zea mayes) and soybean (Glycine max) were evaluated for these isolates. Acer velutium and Acer cappadocicum were good hosts for both isolates. In the soybean plant, Reproductive factor (Rf) was less than 1 and therefore that is not regarded as a host; although nematode penetrated in the root. In the corn and olive plants was observed no penetration of nematode in the roots, therefore these plants were considered as non host plants. The results of this research demonstrated morphometric variability and high host preference in the Iranian isolates of Pratylenchus vulnus.