Sclerospora graminicola in pearl millet seeds and its transmission

Abstract

Sclerospora graminicola (Sacc.) Schroet. inoculum may be present in pearl millet seed either as oospores externally or in the form of dormant mycelium internally. Oospore inoculum was detected by using the washing method, and mycelial infection by the modified embryo count procedure. Fifty-nine seed samples out of ninety-three obtained from different sources were found contaminated with oospores whose viability was checked by the tetrazolium test. Percentage of viable spores ranged from 5.5 to 20.2. Forty-three samples showed mycelial infection of 0.1-7.5 Per cent in various parts of the seed. Seeds from healthy-looking plants are not necessarily pathogen-free. Transmission was obtained from a two-year-old seed sample contaminated with oospores and from mycelium. The significance of the results with particular reference to survival of inocula, development of epidemics and quarantine implications in international movement of germplasm are discussed.