IDENTIFICATION OF SOIL-CULTURABLE MICROMYCETES IN AVOCADO ORCHARDS IN NORTHEASTERN MEXICO.

Mexico is the world's leading producer and exporter of avocado (Persea americana Miller). There are few studies on soil microorganisms associated with this crop, which are important to establish the role they can play in the production system and their use in different areas of interest. In this re-search, the biodiversity of cultivable micromycetes in the soil of five avocado orchards located in two municipalities of the state of Nuevo León was determined. The isolates obtained were grouped into morphotypes and identified to genus level or grouped by common morphological characteristics. Shannon-Wiener, Simpson, and Margalef diversity indices were determined for morphotypes, as well as for and genera and groups of micromycetes with common characteristics in each orchard. The Hutcheson's test (p= 0.05) was performed to determine significant differences between Shannon-Wiener diversity index of genera and micromycetes with common characteristics between orchards. A total of 518 isolates were obtained and classified into 291 morphotypes that were grouped into 44 genera and 7 groups with common characteristics. Hutcheson's test showed that the Shannon-Wiener index of genera and groups of a single orchard is different to the others. The sterile mycelium group was the most abundant in four of the five orchards. Genera reported as phytopathogens (Fusarium, Verticillium), entomopathogens (Beauveria, Paecilomyces, Metarhizium) and mycoparasites (Trichoderma, Gliocladium) were identified. In addition, 28 new genera associated with avocado orchard soil are reported in this research. [ABSTRACT FROM AUTHOR]