Abstract

MONTERO TAVERA, Víctor et al. Genetic, pathogenic and morphological diversity of fungi Colletotrichum gloeosporioides (Penz.) from Michoacan, Mexico. Rev. Mex. Cienc. Agríc [online]. 2010, vol.1, n.2, pp.159-174. ISSN 2007-0934.

The fungi Colletotrichum gloeosporioides, is the agent that causes anthracnose and the main limitation to the harvest of commercial quality Hass avocado (Persea americana). The genetic diversity of the population of this fungus has been studied in several parts of the world, yet in Mexico, its population structure, and especially the components of its diversity, are unknown. The genetic, pathogenic and morphological diversity was determined for 21 monoconidial strains of Colletotrichum gloeosporioides from Michoacán, Mexico. The genetic diversity was estimated by means of random amplified DNA polymorphism, and by determining the profiles of isoenzymes of each monoconidial strain. Pathogenic diversity was measured with the invasive capacity of avocado pulp and the growth rate in vitro was determined by comparing the characteristics of the mycelia of each monoconidial strain. Results showed a high diversity of Colletotrichum gloeosporioides with a genetic variability index of 0.3031, and the most accurate estimator was the random amplified DNA polymorphism (genetic variability index= 0.344) and isoenzyme profile (genetic variability index= 0.35). The typical characteristics were white mycelia, cotton-like consistency, white colony, random mycelia growth and short hyphae on the growth border. There was no relation between the pathogenicity measured as the invasive capacity of the pulp and this growth rate in vitro. The group analyses determined that the relations between the strains are established based mainly on the origin and, in a secondary manner, on the symptom in the fruit.

Keywords : Persea americana; cluster analysis; isoenzymes; RAPD.