A Laboratory Method to Evaluate Lettuce Cultivars for Tipburn Tolerance. I. J. Misaghi, Department of Plant Pathology, University of Arizona, Tucson 85721. R. G. Grogan, Department of Plant Pathology, University of California, Davis 95616; and F. V. Westerlund, Moran Seed Company, Salinas, CA 93908. Plant Dis. 65:342-344. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-342.

Mature plants from eight lettuce (Lactuca sativa var. capitata) cultivars were selected randomly during harvest from fields in Arizona and California and subjected to a constant temperature of 30 C and 35 ± 5% relative humidity with 12 hr of light (18,000 lux) daily in growth chambers. Plants were rated for tipburn incidence and severity after 3 and 5 days. Field and laboratory ratings for tipburn tolerance of the cultivars were consistently correlated.