VIEW ARTICLE

Temperature-Dependent Resistance to Tobacco Ringspot Virus in L8, a Necrosis-Prone Tobacco Cultivar. James W. Hendrix, Department of Plant Pathology, University of Kentucky, Lexington 40506; Phytopathology 62:1376-1381. Accepted for publication 12 June 1972. DOI: 10.1094/Phyto-62-1376.

The burley tobacco breeding line L8, which has black shank resistance derived from Nicotiana longiflora, was resistant to tobacco ringspot virus (TRSV) at 24 C. Resistance was expressed as a necrotic reaction on the inoculated leaves and the absence of systemic infection. In a small percentage of plants, a systemic necrotic reaction occurred. At 35 C, L8 plants became systemically infected, and symptoms were considerably different from those of plants incubated at 24 C. Hybridizing L8 with standard cultivars resulted in loss of resistance, as measured by systemic invasion, but the nature of the systemic symptoms was dependent upon the percentage of L8 germplasm. Resistance to TRSV was not related to resistance to tobacco mosaic virus. L8 tends to have necrotic reactions to stresses, but the factors controlling the various reactions appear to be inherited differently.