Confirmation of the occurrence of teliospores of Hemileia vastatrix in Brazil with observations on their mode of germination

• Autor(a) principal: Fernandes,Ronaldo de Castro
• Data de Publicação: 2009
• Outros Autores: Evans,Harry Charles, Barreto,Robert W.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Tropical plant pathology (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1982-56762009000200005
• topic: Abnormal germination; coffee leaf rust; genetic instability; rust lineages; SEM studies

The occurrence of teliospores of Hemileia vastatrix in Brazilis confirmed for the first time and clearly documented under light microscopy and SEM. Additionally, voucher specimens of leaves containing sori with germinated and non-germinated teliospores were deposited in a local herbarium (Herbário VIC). The previous publication claiming to provide an account of the occurrence of teliospores of H. vastatrix in Brazil did not include appropriate images or an indication of voucher specimens. Observations during 2006, at a site in the Zona da Mata coffee-growing region of Minas Gerais, Brazil, revealed the presence of teliospores during the winter months (July-September), probably triggered by the fall in temperature and decreasing rainfall immediately prior to and during this period. A significant proportion of these teliospores exhibited abnormal germination: the number of promycelial cells varying from three to seven, with or without the production of sterigmata. Basidiospores were variable in size and shape, possibly indicating genetic instability, and this is discussed in relation to the life-cycle of coffee leaf rust.