Disease Resistance in Wild Pennisetum Species. Jeffrey P. Wilson, Research Plant Pathologist, USDA-ARS Forage and Turf Unit, University of Georgia Coastal Plain Experiment Station, Tifton 31793. Wayne W. Hanna, Research Geneticist, USDA-ARS Forage and Turf Unit, University of Georgia Coastal Plain Experiment Station, Tifton 31793. Plant Dis. 76:1171-1175. Accepted for publication 21 July 1992. 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-76-1171.

Ninety-eight accessions of wild Pennisetum glaucum from the primary gene pool (1° Pennisetums) and 27 species from the tertiary gene pool (3° Pennisetums) of P. glaucum were evaluated for disease resistance. The 1° Pennisetums were also evaluated for morphologic traits to further differentiate the accessions. The 1° Pennisetums were evaluated for resistance to Pyricularia grisea, Puccinia substriata var. indica, and Moesziomyces penicillariae and also for height, diameter of the fifth internode, number of nodes, heading date, and panicle length and morphology. Species in the 3° gene pool were evaluated for resistance to P. s. indica, Pyricularia grisea, Bipolaris setariae, Drechslera dematioidea, Phyllosticta penicillariae, and Exserohilum rostratum. Within the 1° Pennisetums, frequencies of plants resistant to Pyricularia grisea and P. s. indica averaged 90.5 and 29.8%, respectively. Smut severities averaged 3.8%. Twenty-two accessions with characteristics of the subspecies stenostachyum tended to have greater frequencies of rust-resistant plants. Forty-six accessions with characteristics of the subspecies monodii were more smut-resistant. The 3° Pennisetums were immune to P. s. indica. On the basis of reactions to the leaf blighting fungi, the 3° species were clustered into two groups, one with relatively high levels of resistance to the five pathogens and the other with less effective resistance.