Caracterização fisiológica de isolados selvagens e transformados de Trichoderma spp.

Abstract

A variety of multipurpose strains of Trichoderma isolates are commercially available for biological control of plant pests and diseases, as well as being in the native and anthropized field representing global diversity. The aim of this work is to analyze the growth physiology, morphometry of isolates of Trichoderma spp. The experiments were conducted in three stages: i) Growth physiology: in a population of 25 isolates, in a completely randomized design with three replications, the following factors were evaluated: factor 1: isolates effect (25), factor 2 - types effect stress (three - sorbitol, NaCl and no stress), factor 3 - temperature effect (10 oC, 20 oC and 27 oC). i) daily for seven days the diameter of the colony (mm) was measured; ii) morphology and morphometry: from the previously cultivated isolates the morphological colonies were characterized, the conidia morphometry was performed and the conidia productivity was evaluated in each imposed morphocultural condition. Parametric and nonparametric hypothesis tests and multivariate analyzes were used to distinguish the treatments. From the growth physiology we observed the individual effect of the isolates, identifying the SLV1 isolate by presenting the highest growth average in all evaluated days; The stresses that most inhibited the growth of isolates were NaCl followed by sorbitol, with variations in insensitivity to the stresses used, however reflecting in reproductive disability. From the morphology and morphometry the isolates that presented the largest spore length were SLV 5, SLV8 and SLV 10 and the stress reduced the conidia size from the largest to the smallest statistically represented by potato-dextrose-agar, sorbitol and NaCl. It is concluded from this work for field tests that the SLV1 isolate is a candidate as a biological control agent of plant diseases.