VIEW ARTICLE

Growth and Distribution of Fusarium oxysporum f. sp. lycopersici in Near-Isogenic Lines of Tomato Resistant or Susceptible to Wilt. D. M. Elgersma, Research Plant Pathologist, Phytopathologisch Laboratorium “Willie Commelin Scholten”, Baarn, The Netherlands; W. E. MacHardy(2), and C. H. Beckman(3). (2)(3)Research Associate and Professor of Plant Pathology, respectively, University of Rhode Island, Kingston, 02881, (2)Present address: Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada. Phytopathology 62:1232-1237. Accepted for publication 8 May 1972. DOI: 10.1094/Phyto-62-1232.

The buildup and distribution of Fusarium oxysporum f. sp. lycopersici in near-isogenic lines of susceptible and resistant tomato were investigated. Spore-size vinyl tracer particles introduced into the vascular systems showed no differences in the distribution pattern between the two isolines. Buildup of the pathogen, when calculated on the basis of infested vessels only, was found to be comparable in both isolines. Secondary distribution, however, was limited in the resistant isoline in contrast to the susceptible one in which all vascular bundles gradually became infected. It was concluded that a factor(s) which prevents distribution of the parasite is responsible for the single dominant gene type of wilt resistance in tomato.