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

Resistance to watermelon mosaic virus (WMV) was transferred by success ive backcrossing with selection from Cucumis melo PI 414723 to three m elon varieties. Levels of resistance to virus accumulation in leaf tis sue were evaluated using enzyme-linked immunosorbent assay, and proced ures are described to select resistant individuals efficiently and acc urately in segregating populations. Resistance is controlled by a sing le 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 lea ves. 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 cucumb er mosaic virus, papaya ringspot virus, and zucchini yellow mosaic vir us, did not overcome resistance to WMV conferred by Wmr.