RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISMS IN FUSARIUM-OXYSPORUM FSP DIANTHI AND OTHER FUSARIA FROM DIANTHUS SPECIES

DNA restriction fragment length polymorphisms (RFLPs) among 46 isolate s of Fusarium oxysporum from Dianthus spp., representing the known ran ge of pathogenicity in carnation, were determined using total DNA dige sted with the restriction enzyme HindIII and a previously described pr obe, D4. Distinct multiple band RFLP patterns were found, which deline ated RFLP groups as follows: (i) F. oxysporum f.sp. dianthi races 1 an d 8; (ii) F. oxysporum f.sp. dianthi races 2, 5 and 6; (iii) F. oxyspo rum f.sp. dianthi race 4; (iv) a recently described race of F. oxyspor um f.sp. dianthi (wilt-causing isolates from D. caryophyllus formerly classified as F. redolens); (v) wilt-causing isolates from D. barbatus formerly classified as F. redolens and (vi), (vii) and (viii), three further recently described races of F. oxysporum f.sp. dianthi. Isolat e groups derived from analysis of RFLPs were consistent with existing and recently described vegetative compatibility groups (VCGs) in F. ox ysporum f.sp. dianthi, but not in all cases with races. Isolates of F. oxysporum and F. proliferatum not associated with wilt disease had si mpler RFLP patterns (with one exception) that were not associated with VCGs.