Antagonismo in vitro de trichoderma sp. y diversidad genética de moniliophthora roreri h.c evans del cacao (theobroma cacao l.) en la provincia de Orellana

Abstract

The fungus Moniliophthora roreri H.C Evans has caused important losses in cocoa crop production because there are no biological control strategies or information on the genetic diversity of the pathogen in Orellana province, therefore, this investigation aimed to study the in vitro antagonism of Trichoderma sp. and the genetic diversity of Moniliophthora roreri H.C Evans of cocoa (Theobroma cacao L.) in Orellana province. A bifactorial randomized complete design was used, with nine species of Trichoderma sp. (factor A) and 21 strains of M. roreri (factor B) with three repetitions. Confrontations were carried out using the dual culture technique, to evaluate the antagonism and analyze it using Tukey's test at 5%. For genetic diversity, M. roreri genomic DNA was extracted using the Promega Wizard Kit, and M. roreri isolates were grouped by locality and then PCR was performed with RAPD markers. The results showed that Trichoderma harzianum was the species that generated the highest percentage of inhibition on M. roreri, and strain C25 from the places as La Belleza CCN51 in Francisco de Orellana canton was the most inhibited, in the same way the species of Trichoderma sp. exhibited antagonistic capacity of grade 1 and grade 2, in terms of genetic diversity, La Belleza stood out with seven genotypes and a Shannon index of 34.58. It is concluded that, Trichoderma sp. proved to be an antagonistic fungus good at combating pathogens and limiting the growth of M. roreri. Regarding to diversity, La Belleza was the place with the highest number of multilocus genotypes in all the analyses, and it was the most diverse.