Apparent Immunity and Tolerance to Tomato Big Bud Disease in Lycopersicon peruvianum and in Two of Its Tomato Hybrids. P. E. Thomas, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Irrigated Agriculture Research and Extension Center, Route 2, Box 2953A, Prosser, WA 99350. Sher Hassan, Professor and Chairman, Plant Pathology Department, NWFP Agricultural University, Peshawar, Pakistan. Plant Dis. 76:139-141. Accepted for publication 24 July 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source, The American Phytopathological Society, 1992. DOI: 10.1094/PD-76-0139.

All plants in a seed lot of Lycopersicon peruvianum, U.S. Department of Agriculture Plant Introduction (PI) No. 128655, and in seed lots of two F₅ hybrid progenies of PI 128655 × tomato either did not become infected (apparent immunity) or were infected without symptoms (tolerance) after graft inoculation using tomato tissue infected with tomato big bud disease. The same germ plasm was previously shown to contain the same expressions of resistance and tolerance against three phloem-limited viruses—beet curly top, tomato yellow top, and potato leafroll.