VIEW ARTICLE

Ecology and Epidemiology

Pollination Effects on Pearl Millet Ergot. R. P. Thakur, Plant pathologist, Cereal Improvement Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), 1-10-45/46 Chikoti Gardens, Begumpet, Hyderabad 500 016, Andhra Pradesh, India; R. J. Williams, principal cereal pathologist, Cereal Improvement Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), 1-10-45/46 Chikoti Gardens, Begumpet, Hyderabad 500 016, Andhra Pradesh, India. Phytopathology 70:80-84. Accepted for publication 24 June 1979. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-80.

Pollination of inflorescences of three pearl millet male-sterile lines before or at the same time as inoculation with Claviceps fusiformis conidia reduced ergot to less than 3% infected florets. Pollination 16 hr after inoculation reduced ergot to 7–21% compared with 60–86% for inoculated, nonpollinated checks. Pearl millet pollen germinated in 1 hr when incubated in a 10% sucrose solution, whereas C. fusiformis conidia did not germinate in less than 16 hr of incubation. Results from inoculation of inflorescences of male-sterile lines at different stages of flowering in the absence of pollen, along with observations on the effects of pollination on stigma morphology and longevity, lead us to conclude that ergot infection in pearl millet occurs mainly through the stigmas, and that pollination protects against infection probably because it induces rapid withering of stigmas. The results help explain the increased ergot susceptibility of pearl millet F₁ hybrids compared with traditional cultivars, and have important implications for ergot-resistance screening methods and for the development of cultural measures to control this disease.