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Resistance to Bacterial Canker in Tomato (Lycopersicon hirsutum LA407) and its Progeny Derived from Crosses to L. esculentum

November 2001 , Volume 85 , Number  11
Pages  1,171 - 1,176

David M. Francis and Eileen Kabelka , Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, Wooster 44691 ; Julia Bell , Department of Botany and Plant Pathology, Michigan State University, East Lansing 48824 ; Barb Franchino , Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center ; and Dina St. Clair , Department of Vegetable Crops, University of California, Davis 95616

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Accepted for publication 11 July 2001.

Bacterial canker caused by Clavibacter michiganensis subsp. michiganensis causes significant yield losses on tomatoes grown in a humid environment. This study was conducted to identify a source of resistance that could be easily crossed to cultivated tomato and to study the inheritance of resistance. Diverse bacterial strains representative of the major DNA fingerprint classes endemic to North America were used to screen germ plasm and populations derived from wide crosses. Partial resistance to genetically characterized and distinct strains of C. michiganensis subsp. michiganensis was identified in a wild relative of cultivated tomato, Lycopersicon hirsutum Lycopersicon accession (LA)407. The level of resistance in LA407 was not significantly different from that of the resistant L. peruvianum control, LA2157. Resistance from LA407 was recovered in lines from a BC2S4 inbred backcross (IBC) population in both greenhouse and field trials. Linear correlations between field and greenhouse resistance scores were significant, though correlation coefficients tended to be low. Variance components for genetic and environmental variation in resistance were used to estimate broad-sense heritability in the IBC population. These estimates were moderate to high, ranging from 0.34 to 0.85. The number of genes contributing to resistance was estimated from four trials, with most estimates falling in the range of one to three loci. Two lines from the IBC population, IBL 2353 and IBL 2361, were identified as sources that retain resistance in a genetic background that has a theoretical L. esculentum genome content of 87.5%.

Additional keywords: inbred backcross

© 2001 The American Phytopathological Society