Evaluation of Cucumis ficifolius A. Rich. Accessions for Resistance to Fusarium Wilt

Aims: Fusarium wilt of melon (Cucumis melo L.), which is caused by Fusarium oxysporum f. sp. melonis is regarded as a severe disease worldwide. Among the races (0, 1, 2 and 1,2), no gene conferringhigh resistance to race 1,2 has been identified in melon Wild Cucumis species have been reported to possess resistance to some melon diseases, and some of the methods of overcome to the reproductive barriers in genus Cucumis interspecific crosses were reported. We evaluated C. ficifolius for novel resistance to F. oxysporum f. sp. melonis and searched for novel sources of resistance. Study Design: A total of 10–20 plants were evaluated for each accession. Results were expressed as mean values and standard errors. Disease severity was log-transformed and data were analyzed using least-squares analysis of variance (ANOVA). A post hoc Tukey- HSD test was performed to compare disease severity among the accessions. Place and Duration of Study: Tokyo University of Agriculture and Technology, and Plant Biotechnology Institute, Ibaraki Agricultural Center between October 2008 and September 2011. Methodology: Inoculation was conducted using a root dip method. The resistance to each race was evaluated 21 days after inoculation according to a 0–3 disease severity scale (0=no symptoms, 1=small lesions on leaves, 2=leaves strongly affected, 3=plant death). Results:All inoculated accessions showed susceptibility both in race 0 and 1. In race 2 and 1,2, only the accession PI 273648 showed resistance to both. However, the other accessions showed susceptibility to race 2 and 1,2 and the symptoms were almost severe. Conclusion: These results suggest that the accession PI 273648 would be a suitable genetic resource to breed the melon cultivar, which has resistance to race 2 and 1,2