DISCRIMINATION BETWEEN ALFALFA AND POTATO ISOLATES OF VERTICILLIUM-ALBO-ATRUM USING RAPD MARKERS

Random amplified polymorphic DNA (RAPD) of total DNA was used to study genetic variability within 35 alfalfa and potato isolates of Verticil lium albo-atrum, the causal agent of Verticillium wilt. With five sele cted RAPD primers, patterns were clearly different between the alfalfa and the potato isolates. A significant (37%; P < 0.002) portion of th e total genetic variance was attributable to differences between the p otato and the alfalfa isolates. These results suggest that these alfal fa and potato isolates are genetically distinct. Combined with previou s inoculation studies these results are in agreement with the presence of host adaptation in V. albo-atrum and support the creation of a dis tinct taxonomic entity for alfalfa isolates. In addition, one avirulen t potato isolate and one alfalfa isolate were tested and found diverge nt according to RAPD patterns.