Increasing Resistance in Celery to Fusarium oxysporum f. sp. apii Race 2 with Somaclonal Variation. Karen F. Toth, Research Associate, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824. M. L. Lacy, Professor, Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824. Plant Dis. 75:1034-1037. Accepted for publication 5 April 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1034.

Somaclones were regenerated from cell suspension cultures derived from callus of celery cultivar Tall Utah 52-70 HK (moderately resistant to Fusarium oxysporum f. sp. apii race 2). Eighty-one of 350 somaclones screened for resistance to F. o. apii race 2 in either the greenhouse or the field had increased resistance over parental plants grown from seed. Thirty-five highly resistant somaclones (R₀ generation) were self-pollinated, and 10 of the resulting R₁ progeny lines were rated as highly resistant when screened in the field. Most of the R₁ lines resembled parental Tall Utah 52-70 HK plants in appearance, growth rate, and habit. Twenty-six highly resistant plants from 11 R₁ lines were self-pollinated, and nine of the resulting R₂ lines were rated as highly resistant to F. o. apii race 2 in field trials. These lines were very similar horticulturally to the parent cultivar. The lines developed from this work could provide a source of increased resistance to F. o. apii race 2 for celery producers.

Keyword(s): Fusarium yellows, tissue culture.