VIEW ARTICLE

Resistance

Effects of Inoculation and Pollination on Smut Development in Near-Isogenic Lines of Pearl Millet. Homer D. Wells, Research plant pathologist, U. S. Department of Agriculture, Agricultural Research Service, Tifton, GA, 31793; Wayne W. Hanna, and Glenn W. Burton. Research geneticists, U. S. Department of Agriculture, Agricultural Research Service, Tifton, GA, 31793. Phytopathology 77:293-296. Accepted for publication 25 August 1986. 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, 1987.. DOI: 10.1094/Phyto-77-293.

Inoculating pearl millet heads during the first 72 hr after emergence with a sporidial suspension of Tolyposporium penicillariae in the late afternoon (1600–1700 hours) and covering the heads overnight (until 0800–0900 hours) with prewetted polyethylene bags appeared adequate to assure smut infection in a susceptible host. The tr gene that removes plant trichomes, stylar branches, and pleiotropically affects a number of other plant characteristics conferred a high level of smut resistance. The male sterile lines in the absence of pollen had the highest level of smut infection, demonstrating that pollination is a major factor inhibiting smut development. Age of florets at the time of inoculation was a major factor regulating smut development. Timing of pollination of inoculated plants significantly influenced smut development, especially when pollination was delayed more than 72 hr after inoculation. Between the near-isogenic lines there appeared to be genetic differences in smut resistance because dwarf, late, inbred 23D was significantly more resistant than tall, early 23E.