Ergot Susceptibility in Relation to Cytoplasmic Male Sterility in Pearl Millet. R. P. Thakur, Senior Plant Pathologist, Cereals Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, A.P. 502 324, India. V. P. Rao, and S. B. King. Research Associate, and Principal Plant Pathologist, Cereals Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, A.P. 502 324, India. Plant Dis. 73:676-678. Accepted for publication 15 February 1989. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0676.

The association of cytoplasmic male sterility with susceptibility to ergot (caused by Claviceps fusiformis) in pearl millet was studied in seven cytoplasmic male-sterile (CMS) lines (A lines), their corresponding maintainer lines (B lines), 10 pollinator lines (R lines), and 48 F₁ hybrids (A × R and B × R). Four of the seven A lines were significantly more susceptible (90–97% severity) than their corresponding B lines (54–77% severity). All A × R hybrids except four were significantly more susceptible than their corresponding B × R hybrids, indicating the positive association of sterile cytoplasm with ergot susceptibility. The cytoplasmic effect on ergot susceptibility was significant in 20 of the 24 A/ B × R hybrids. The higher ergot susceptibility of A lines and A × R hybrids, compared with B lines and B × R hybrids, could be attributed to the cytoplasmic, nuclear, and cytoplasmic × nuclear factors affecting flowering events that influence ergot susceptibility. Implications of these findings in breeding CMS-based F₁ hybrids are discussed.

Keyword(s): Pennisetum glaucum.