Resistance of Maize Hybrids and Inbreds Following Silk Inoculation with Three Isolates of Fusarium graminearum. L. M. Reid, Plant Research Centre, Agriculture Canada, Ottawa, Ontario, Canada K1A OC6. D. Spaner, D. E. Mather, A. T. Bolton and R. I. Hamilton. McGill University, Macdonald Campus, 21111 Lakeshore Rd., Ste-Anne-de-Bellevue, Québec, Canada H9X 3V9; and Plant Research Centre, Ottawa, Ontario, Canada K1A OC6. Plant Dis. 77:1248-1251. Accepted for publication 10 September 1993. Copyright 1993 The American Phytopathological Society. DOI: 10.1094/PD-77-1248.

Maize hybrids and inbred lines, including six quality protein maize (QPM) inbreds, were evaluated for resistance to ear rot after silk inoculation with three Fusarium graminearum isolates. Conidial suspensions were injected into the upper silk channel to approximate natural infection. Although significant isolate effects and genotype × isolate interactions were observed, the rankings of maize genotypes were similar across isolates. One of the isolates appeared to be less aggressive, and this may account for the observed isolate effects and interactions. Each of the three isolates identified two inbreds (CO272 and CO325) and one hybrid (Pride K127) as the most resistant. All of the QPM material tested was susceptible. It was concluded that, in breeding programs, one sufficiently aggressive isolate or a mixture of isolates can be used to screen for resistance.