Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/1/1997
Publication Date: N/A
Technical Abstract: Tilletia indica, the causal agent of Karnal or partial bunt of wheat, produces large brown echinulate teliospores as do many species of Tilletia. Identification of similar looking species of Tilletia is difficult without accurate knowledge of the host. Currently, PCR is required to distinguish between T. indica and T. horrida. In this study, herbarium specimens of T. .indica, T. horrida, T. lolii, T. eragrostidis, and an undescribed Tilletia from bunted Lolium spp. seeds found in Oregon, Tennessee, and Australia were examined. Teliospores were characterized using light microscopy and scanning electron microscopy. Shape, size, ornamentation and color of the teliospores were analyzed. Mature T. indica, teliospores, ranging from 28- 48 um in diameter, were dark red-brown, often opaque, with a densely ornamented exospore. The undescribed Tilletia from Lolium seeds ranged from 25-40 um in diameter, with a lighter yellowish- or golden-brown color, ,less frequently dark brown, and a more coarsely spined exospore. Tilletia horrida and T. eragrostidis, with spores ranging from 22-34 um and 27-36 um, respectively, and Tilletia lolii were distinguished by exospore ornamentation. Molecular confirmation may continue to be helpful in cases were certain morphological characters overlap or when the stage of maturity of the teliospore is not known.