Screening and Morphological Characterization of Melons for Resistance to Fusarium oxysporum f.sp. melonis Race 1.2

Abstract

A total of 110 melon accessions with different geographical origins (18 countries) were screened for resistance to Fusarium oxysporum f.sp. melonis race 1.2 (pathotypes 1.2Y and 1.2W) using two artificial inoculation procedures. Twelve accessions showed some resistance to one or both strains. Three Japanese accessions, Shiro Uri Okayama (var. conomon), Kogane Nashi Makuwa, and C-211 (var. makuwa), and a Portuguese accession, BG-5384 (var. cantalupensis), showed the highest levels of resistance to both strains. The remaining eight accessions (all var. inodorus) had some level of partial resistance to 1.2W only. To our knowledge, this is the first time a high level of resistance to F. oxysporum f.sp. melonis race 1.2 has been identified in melon accessions of Western origin. The morphological traits of the 12 accessions that showed partial resistance were characterized to assess their suitability as resistance sources in melon breeding programs. Because most of the Western commercial cultivars belong to the cantalupensis, reticulatus, or inodorus botanical varieties, the resistant accessions from these varieties seem to be the most useful sources of resistance in breeding programs for developing melon cultivars of these types resistant to fusarium wilt race 1.2. The Portuguese accession BG-5384 had a high level of resistance within the Western types, and its morphological characteristics were fairly similar to some of the Western commercial cultivars.