SUSCEPTIBILITY OF STRAWBERRY CULTIVARS AND ADVANCED SELECTIONS TO LEAF-SPOT CAUSED BY MYCOSPHAERELLA-FRAGARIAE

Seventeen strawberry (Fragaria xanartassa Duchesne) cultivars and six selections were tested under greenhouse conditions for susceptibility to leaf spot induced by Mycasphaerella fragariae (Tul.) Lindau. The le vel of susceptibility was evaluated based on maximum disease severity and area under the disease progress curve (AUDPC). The 23 genotypes we re ranked based on AUDPC and grouped according to their susceptibility . Cluster analysis for AUDPC gave four groups corresponding to low, mo derate, high, and very high susceptibility to leaf spot. 'Annapolis', 'Chambly', 'Glooscap', 'Redcoat', and 'Veestar' consistently showed a low level of susceptibility. The selections SJ89700-1 and SJ8518-11 an d 'Tribute' showed a very high level of susceptibility, and the remain ing cultivars were grouped as either moderately or highly susceptible.