Isolados de Alternaria spp. patogênicos ao fedegoso (Senna obtusifolia) foram estudados quanto aos aspectos morfológicos e padrões isoenzimáticos, em gel de poliacrilamida. Com base nas características culturais, morfologia de colônias e morfometria de conídios, verificou-se que 11 dos 13 isolados pertenciam à espécie A. cassiae e os outros dois à A. alternata. Os resultados da análise eletroforética corroboraram as informações obtidas por meio de critérios morfológicos. Portanto, esta técnica tem potencial para ser usada na separação destas espécies de Alternaria. A ocorrência de mais de uma espécie deste gênero fúngico em S. obtusifolia foi constatada, ampliando o número de patógenos a serem avaliados no programa de desenvolvimento de um bioherbicida para esta espécie de planta daninha.

The Cerrado has wide plant diversity, including orchids. These plants need symbiosis with fungi for their germination to occur in the wild. In vitro or asbiotic cultivation is an alternative for the production of seedlings of this species. This diversity of orchids makes it much appreciated as pot plants, landscaping, with high commercial value. The objective of this work was to carry out the study for the development of a protocol for the germination and in vitro development of orchids. The experiment was carried out at the LABIOTEC Biotechnology Laboratory of the Federal Institute Goiano Campus Urutaí-GO. Catasetum sp native capsules from Goiás State, containing mature seeds were collected and disinfected in 50% sodium hypochlorite solution for 30 minutes and in laminar flow were washed four times in distilled and autoclaved water. They were then seeded in vitro in 258 mL glass vials containing 30 mL of MS medium enriched with vitamins and 0.0 Tryptone; 1.0; 2.0 and 3.0 g L-1. The pH of the medium was adjusted to 5.2 ± 0.1. The average time for germination and development of the protocorms varied from 3 to 7 days after sowing for the species under study. The dosage of 2.0 g L-1 is efficient for the development and maintenance of in vitro Catasetum protocorms up to 333 days. There was no development of shoot of Catasetum seedlings in any of the evaluated treatments. It was observed that the 3.0 g L-1 Tryptone dosage presented higher rates of fungal and bacterial contamination and oxidation