Natural Incidence of Peanut Stunt Virus Infection in Hybrid Populations of Trifolium ambiguum × T. repens. J. A. Anderson, Former Graduate Assistant, Department of Plant Pathology, University of Kentucky, Lexington 40546. S. A. Ghabrial, and N. L. Taylor. Professor, Department of Plant Pathology, and Professor, Department of Agronomy, University of Kentucky, Lexington 40546. Plant Dis. 75:156-159. Accepted for publication 18 July 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-0156.

A spaced-plant nursery was established in 1988 to evaluate the reactions to peanut stunt virus (PSV) of populations of kura (Trifolium ambiguum) and white (T. repens) clovers, F₁ hybrids H-435 and H-262, F₂ plants, first and second backcross plants of one F₁ hybrid to white clover, and first backcross intercross plants. No PSV infection was detected in one of four first backcross progenies and two kura clover populations after 11 mo of field exposure. Two F₁ hybrids and white clover checks had moderate to severe symptoms and high incidence of PSV infection. Second backcross progenies and backcross intercross progenies were apparently tolerant to PSV infection and had few or no symptoms despite very high virus incidence. Introgression of genes for PSV resistance from kura clover to white clover was not evident with the hybrid populations tested. Prospects for obtaining genes for resistance to PSV from the two interspecific hybrids tested are doubtful.