Diversidad genética de Trichoderma spp. en Venezuela, determinada mediante análisis combinado ITS-AFLP

The genetic diversity among 68 Trichoderma isolates from different cultivars, substrates and localities was established by ITS-AFLP analysis. The ribosomal DNA region ITS1-5.8S-ITS2 was sequenced and amplified with the primers ITS1 and ITS4. In the case of AFLP, four oligonucleotide combinations were used. The genetic relationships between isolates were analyzed by the combined use of Principal Component Analysis, Cluster analysis, and the adjustment of an External Logistic Biplot over dissimilarity data using Jaccard, simple coupling, Dice and Rogers, and Tanimoto coefficients. Nine species were identified, and the most abundant were Hypocrea lixii (anamorf Trichoderma harzianum) and T. koningiopsis, with 22 and 20 isolates respectively. They were followed by Hypocrea virens (anamorf T. virens), Trichoderma ghanense; Trichoderma asperellum and Trichoderma brevicompactum, with 7, 6, 4 and 4 isolates, respectively. The