Rizobactérias promotoras do crescimento de mudas micropropagadas de bananeira e agentes de biocontrole do mal-do Panamá (Fusarium oxysporum f. sp. cubense)

Abstract

Banana is an important fruit crop in tropical countries, including Brazil as one of the major producer in the world. Rhizomes (suckers), providing high risks of pathogen contamination and usually are used for the vegetative propagation of banana. The in vitro micropropagated plants are an alternative technique to that crop vegetative propagation, producing health and homogeneous plantlets. However, the technique removes microorganisms that could improve plant establishment. The introduction of rhizobacteria could induce rooting of plantlels, promote plantlet growth and suppress pathogen infection. The aims of the study were: a) isolate and select rhizobacteria able to solubilize phosphate, produce siderophores, indolacetic acid, and inhibit Fusarium oxysporum f. sp. cubense; b) to evaluate the potential of rhizobacteria to growth promotion of banana plantlets in rooting and acclimatization phases. A total of 200 rhizobacteria were assayed and five were positive to indolacetic acid production (PC04, PC45, PC107, PC37, PC05); three strains were selected as potential biocontrol agents to F.oxysporum f. sp. cubense (262C, 106A and 23C). In greenhouse studies the acclimatization phase was the best time to introduce the rhizobacteria to promote growth, where strain PC107 had the highest performance. Mix of biocontrol rhizobacteria didn't reduce the Foc severity.This work confirms the potential of rhizobacteria in increasing the production of banana plantlets.