Sources of Resistance to Viruses in Two Accessions of Cucumis sativus 

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Cucurbit Genetics Cooperative Report 8:9-12 (Article 5) 1985

Provvidenti, R.
Department of Plant Pathology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456

Recently we have determined that two accessions of Cucumis sativus ‘Surinam’ and ‘TMG-1’ are valuable sources of resistance to the most common viruses affecting this species in the United States.

‘Surinam’, a cultivar from the South American country of the same name, possesses a single recessive gene (wmv-l-l), which confers resistance to watermelon mosaic virus 1 (WMV-1) (2). Following inoculation with this virus, plants respond with a mild systemic mottle, usually confined to one or two leaves. Subsequent growth is free of symptoms, and plants remain as vigorous as the healthy controls. ‘Surinam’ appears also to be resistant to some isolates of watermelon mosaic virus 2 (WMV-2) but susceptible to others. It also is susceptible to cucumber mosaic virus (CMV) and zucchini yellow mosaic virus (ZYMV) (2). This cultivar is of intermediate maturity, producing cylindrical-stippled fruits averaging about 20 cm in length.

‘TMG-1’ derived from a single plant selection of an old Chinese cultivar from Taiwan (1). This line is resistant to CMV, WMV-1, WMV-2 and ZYMV. Of particular value is its resistance to ZYMV, since all the American cultivars are very susceptible to this virus. Infected plants exhibit severe foliar mosaic and necrosis, stunting and fruit distortion. Of the two strains known to be present in the Untied States, ZYMV-CT and ZYMV-FL, ‘TMG-1’ reacts with some systemic veinal chlorosis to the former and with localized infection to the latter. Preliminary data on the inheritance of resistance indicate that resistance is conferred by a recessive factor. F1 plants deriving from crosses between ‘TMG-1’ with several commercial cultivars show a high level of hybrid vigor. ‘TMG-1’ possesses excellent horticultural characteristics. Plants are vigorous and of early maturity, fruits are dark-skinned and smooth, about 30 cm long.

Frequently, viruses affecting cucumber, as well as other cocurbits, are concurrently found in the same field, hence the necesssity to develop a new generation of multi-viral resistant cultivars. ‘TMG-1’ provides cucumber breeders with sources of resistance to four viruses.

Literature Cited

  1. Provvidenti, R., D. Gonsalves, and H. S. Humaydan. 1984. Occurrence of zucchini yellow mosaic virus in cucurbits from Connecticut, New York, Florida, and California. Plant disease 68:443-446.
  2. Wang, Y. J., R. Provvidenti, and R. W. Robinson. 1984. Inheritance of resistance to watermelon mosaic virus 1 in cucumber. HortScience 19:587-588.