ChileanJAR

The genetic diversity of Fusarium strains isolated from muskmelons (Cucumis melo L.) was evaluated by RAPD and compared with classical taxonomy, morphological and pathogenicity based analyses. Eighteen isolates collected from commercial fields located between III and VI Regions, Chile, were studied. Morphological taxonomy identified eleven isolates as F. oxysporum, four as F. semitectum, one as F. solani and one as F. subglutinans. The F. oxysporum strains able to cause wilt in muskmelon plants were identified as F. oxysporum f. sp. melonis (Fom). DNA profiles obtained from RAPD assays and cluster analyses showed that the Fom population is genetically heterogeneous and complex. Two sub-populations, FomA y FomB, were observed. The results of the species identification obtained with RAPD and those obtained with morphological analyses were not consistent. One isolate identified via conventional methodology as the F. solani strain was genetically similar to the FomA group, while some strains identified as Fom were genetically similar to those identified as F. semitectum. The genetic diversity of Fusarium and these results show the need for more reliable and easier systems to identify Fusarium species within the genus. At the same time, the role of F. semitectum as a muskmelon pathogen in Chile should be considered.