Field Screening of melon cultigens for multiple race resistance to Fusarium oxysporum f. sp. melonis

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Cucurbit Genetics Cooperative Report 14:55 (article 20) 1991

Timothy J. Ng and J.C. Kantzes
Department of Horticulture and Botany, University of Maryland, College Park, MD 20742 USA

Fusarium wilt is one of the primary diseases limiting melon production in the mid-Atlantic regionsof the U.S. Although multiple races of fusarium wilt have traditionally existed in Euripe, only race 2 has been present in North America until recently. Race 1 was first reported in the U.S. (in Maryland) in 1985 (1). Subsequently, race 0 was reported in Texas (#) and in Maryland (2).

Fungicides and soil fumigants do not provide adequate control of fusarium wilt. the most desirable means of control is through the development of melon cultigens with multiple resistances to the pathogen. Since 1987, screening for fursarium wilt resistance has been underway in a field at the University of Maryland Lower Eastern Shore Research and Education Center in Salisbury, Maryland. This field has been in continuous melon cultivation for over 30 years and is heavily infested with both race 1 and race 2 of F. oxysporum. Results of the screening for theyears 1987 through 1989 were published recently (4).

In 1990, a total of 56 entries were evaluated for their relative susceptibility to the wilt pathogen. As before, the field was fumigated and covered with clear plastic mulch. four replicates of each cultigen were transplanted through the mulch in a randomized complete block design with eight plants per replicate. Normal cultivation practices were observed during the growing season and wilt resistance was assessed in mid-August by counting the number of surviving plants.

Although the majority of the entries suffered greater than 50% mortality in the test, eight new cultigens exhibited better than 88% survival. These were: PSR 15789, PSR 17689, PSR 21789 and PSR 22089 (Petoseed Co. Inc.); ACX-88815 (Abbott & Cobb); and Primo (Northrup-King). Many cultivars known to be resistant to race 2 (e.g. ‘MaryGold’ and ‘Superstar’) succumbed to the combined race situation. The 1991 field screening is currently underway to verify the multiple resistances to the new entries.

Literature Cited

  1. Dutky, E.M., J.E. kantzes, A.D. Brooks and J.G. Kantzes. 1986. a new race of Fusarium oxysporum f. sp. melonis causing wilt of muskmelons in Maryland. Phytopathology 76:563. (Abstract)
  2. Jacobson, D.J. and T.R. Gordon. 1988. Vegetative compatibility and self incompatibility within Fusarium oxysporum f. sp. melonis. Phytopathology 78:668-672.
  3. Martyn, R.D. and J. Amador. 1987. Fusarium wilt (F. oxysporum f. sp. melonis Race 0) of muskmelon in Texas. Plant Dis. 71:469.
  4. Ng. T.J. 1989. Field screening of muskmelon cultigens for multiple race resistance to Fusarium wilt. In: C.E. Thomas (ed.). Proc. Cucurbitaceae ’89: Evaluation and Enhancement of Cucurbit Germplas,. Charleston, SC. pp. 146-148.