In-vitro Germination of Oospores of Sclerospora graminicola, the Green-ear Pathogen of Pearl Millet

Abstract

The green-ear disease of pearl millet caused by Sclerospora gl'aminicola (Sacc.)
Schroet. is seed transmitted as oospores on/with seed and/or mycelium in the embryo
(Arya and Sharma, 1962; Shetty et al.• 1977). It is generally agreed that the
soil-borne oospores of the pathogen provide major source of perpetuation of
disease and primary infection of plants in the field (Suryanarayana, 1962). It has
been shown that leaf debris containing oospores, when added to the soil, resulted
in higher disease incidence as compared to when no infected debris was added to
soil (SiddiqUi and Gaur, 1978). However, role of oospores in causing primary
infection has been questioned by several research workers because it has not been
possible to germinate the oospores convincingly under laboratory conditions. Pande
(1972) reported oospore germination in the laboratory, however, her findings.
have not been confirmed. It was communicated that oospores of S. graminicola
were germinated in the laboratory at ICRISAT, Hyderabad (Dr. S. D. Singh
Personal communication, 1989). Attempts were, therefore, made for in-vitro
germination of S. graminicola oospores at the quarantine laboratory of the National
Bureau of Plant Genetic Resources, New Delhi.