DIFFERENTIATION OF NORMAL AND GIANT VICIA-FABA POPULATIONS OF THE STEM NEMATODE DITYLENCHUS-DIPSACI - AGREEMENT BETWEEN RAPD AND PHENOTYPICCHARACTERISTICS

Two main race groups of the stem nematode, Ditylenchus dipsaci, attack Vicia faba. The aim of this work was to evaluate random amplified pol ymorphic DNA (RAPD) as a source of markers for race identification and variability analysis of D. dipsaci. Thirteen populations of D. dipsac i were tested and one population of both D. myceliophagus and D. destr uctor as outgroup species. Sufficient levels of variation were detecte d to allow a clear distinction between the two D. dipsaci groups. This result was in agreement with the characterization based on morphologi cal differences among races and on the type of faba bean disease sympt oms. The intraspecific variation within D. dipsaci populations associa ted with V. faba was low and no strong correlation could be found betw een the geographical origin and molecular or morphological characteriz ation. RAPDs are a powerful tool for identification of D. dipsaci race s and/or populations.