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Resistance

Disease Response of Sweet Corn Hybrids Derived from Dent Corn Resistant to Maize Dwarf Mosaic Virus. David Anzola, Former graduate student, Department of Plant Pathology, The Pennsylvania State University, University Park 16802, Present address: Fundación Servicio para el Agricultor, Calle Sabana Larga, Cagua, Maracay, Edo. Aragua, Venezuela, S. A.; C. Peter Romaine(2), L. V. Gregory(3), and J. E. Ayers(4). (2)(3)(4)Assistant professor, research assistant, and professor, respectively, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 72:601-604. Accepted for publication 24 August 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-601.

Six sweet corn hybrids developed from a maize dwarf mosaic virus (MDMV)-resistant dent corn inbred were examined under greenhouse conditions for resistance to MDMV strains A and B. All hybrids responded to virus inoculation with a reduced rate of symptom development and some hybrids showed a lower disease incidence compared to plants with susceptible dent or sweet corn germ plasm. The altered disease response was most apparent in the sweet corn hybrid, Cr288 × Cr290. This hybrid developed symptoms in 14–28 days with a 50 to 100% disease incidence whereas susceptible hybrids invariably developed a 100% disease incidence within 7 days. In addition, at an early stage of infection, the level of virus was significantly lower in the six hybrids when compared to susceptible hybrids. The virus-host interaction characteristic of this sweet corn germ plasm is known to be correlated with the expression of disease resistance in dent corn. The results suggest that these hybrids might serve as a potential source of resistance to MDMV.