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Factors Influencing Seed Transmission of Squash Mosaic Virus in Cantaloupe. C. C. Powell, Jr., Department of Plant Pathology, University of California, Berkeley, California 94720, The senior author is now a Research Plant Pathologist, ARS, USDA, Oregon State University, Corvallis 97331; D. E. Schlegel, Department of Plant Pathology, University of California, Berkeley, California 94720. Phytopathology 60:1466-1469. Accepted for publication 29 April 1970. DOI: 10.1094/Phyto-60-1466.

Direct seed assay of 50 seed lots from infected cantaloupe plants indicated that 12% of the seeds contained detectable amounts of squash mosaic virus (SqMV) in their embryos, but assay of seedlings indicated that 22% contained virus. In spite of this apparent increase in virus as the seedlings germinated, the observation of 30-day-old plants resulting from seeds of the diseased seed lots showed 13% virus transmission with no detectable symptomless, but infected, plants. Melon wt, size, seed number, seed wt, and percentage of germination were significantly reduced by SqMV infection of the parent plant, but no correlation was found between these reductions and the variable infection percentages in each seed lot. The percentage of virus transmission was about the same in all fractions of seed lots separated on the basis of seed wt. The proportion infected declined from 23 to 5% during 2-year seed storage. Such results indicate that the seed transmission of this virus is determined not only by viral invasion of the seed, but also by the successful maintenance of the host-pathogen relationship during seed formation, storage, and germination.