INHERITANCE OF RESISTANCE TO WATERMELON MOSAIC-VIRUS IN CUCUMIS-MELO L

Resistance to watermelon mosaic virus (WMV) was transferred by successive backcrossing with selection from Cucumis melo PI 414723 to three melon varieties. Levels of resistance to virus accumulation in leaf tissue were evaluated using enzyme-linked immunosorbent assay, and procedures are described to select resistant individuals efficiently and accurately in segregating populations. Resistance is controlled by a single dominant gene designated Wmr. Plants that carry this gene initially develop mosaic symptoms on inoculated leaves, but eventually recover from symptoms, and low or no virus can be detected in the youngest leaves. In contrast, susceptible plants show similar symptoms initially, but remain stunted and symptomatic with reduced fruit yield and fruit quality. Co-infection with other cucurbit viruses, specifically cucumber mosaic virus, papaya ringspot virus, and zucchini yellow mosaic virus, did not overcome resistance to WMV conferred by Wmr.