Caracterização de isolados de fusarium oxysporum F. SP. Cubense (FOC) quanto à compatibilidade vegetativa e à patogenicidade em cultivares de bananeira diferenciadoras de raças no Brasil

Abstract

Fusarium wilt is caused by Fusarium oxysporum f. sp. cubense (Foc) a highly variable pathogen. However, the effect of heterokaryosis on the taxonomic classification and the importance of the formation of a heterokaryon between wild isolates of Fusarium species is still unclear and remains widely debated. Just as parasexual recombination has been reported in F. oxysporum f. sp. cubense, to explain the genetic relationships among isolates belonging to the same race or formae specialis. Asexual and genetically isolated groups identified in these studies are called vegetative compatibility groups (VCG). However, another way of determining races of this pathogen has been through indicator varieties, using the Gros Michel variety for Race 1; Bluggoe for Race 2; Great Naine for Race 4 The present study aimed to determine the genetic diversity among isolates of Foc, through these two techniques in order to identify the races of the pathogen, which do exist in Brazil. The genetics analysis was based on the technique of UPGMA, using the Jaccard similarity coefficient. The technique allowed VCG group the isolates from the Northeast and Southeast regions of Brazil in the VCG 1 and the Northern Region, the VCG 2. While the pathogenicity test allowed us to determine the presence of race 1, through its pathogenicity in Gros Michel and race 4 in Grand Naine. Besides, group them within the same VCG.