Isolation and Characterization of Trichoderma spp., for Their Potential Use in Peanut (Arachis hypogaea) Crops

Abstract

A study was conducted isolation and characterization of Trichoderma spp. for its potential use in a study of isolation and characterization of mycoparasite fungi from soil was carried out by means of rice traps installed in commercial peanut plantations in the west of Nicaragua. From a total of 100 samples, 37 native isolates of Trichoderma spp. were obtained and subjected to different studies. Macroscopic physiological and microscopic morphometric characteristics were evaluated. It was observed that the conidiophores emerge from hyaline hyphae with tubular septate mycelium, these presented characteristics of conical form and verticillate an angle of 450 towards the apical zone of hyaline aspect, with straight ramifications, normally in the form of alternate branches or in pair and sometimes in the form of candelabra, the conidiophores presented a size at the moment of the measurements that oscillated between 25.42 µm - 57.50 µm of length and 1-3 µm of width. The phialides presented a thin citric-form shape at the base, then swollen and curved in the middle part, then becoming thin and pointed in the apical part where the conidia are found in clusters or individually, the sizes at the time of measurement ranged from 9.59 µm - 15µm long. The conidia of all native isolates on the three means of crop propagation, Malt Extract, Papa Dextrose Agar, and Sabouraud Dextrose Agar were 2.92 µm - 5.10 µm long with a green globose to sub-globose coloration. The culture medium did not determine the growth rate, the radial growth rate of the isolates under study depended on time, obtaining the highest growth peak 48 hours after the experiment was established, the length of the conidia did not depend on the isolate or the culture medium, while the size of the phialides did depend on the isolate, in the same way as the conidiophore.