Introduction. Due to the absence of totally effective either economically viable chemical agents for the control of Fusarium wilt, the use of antagonistic microorganisms is of great interest since it could represent a more economically and ecologically sustainable alternative. Objective. To analyze the antifungal effect of the Bacillus amyloliquefaciens CCIBP-A5 strain against Fusarium oxysporum. Materials and methods. The work was carried out in the Laboratory of Applied Microbiology of the Instituto de Biotecnología de las Plantas, Cuba, between September 2017 and June, 2018. The in vitro and in vivo antifungal activity of its culture filtrate and cell against F. oxysporum has been assayed. Results. The results indicated that the metabolites present in the culture filtrate of B. amyloliquefaciens CCIBP-A5 significantly influenced the growth and morphology of the mycelium and the conidia. They also caused oxidative damage to the lipid molecules of F. oxysporum. In addition, this strain showed inhibitory effects on the development of the disease under controlled conditions. These aspects are key when selecting a bacterial candidate as a biological control agent. Conclusions. The results showed that the B. amyloliquefaciens CCIBP-A5 strain, isolated from Musa sp., had an in vitro antifungal effect against the vegetative and reproductive structures of Foc race 1 as well as on the Musa spp.-F. oxysporum interaction. This strain is suggested for the development of a bioproduct for Fusarium wilt management.

Rhizobium-legume symbioses play relevant roles in agriculture but have not been well studied in Ecuador. The aim of this study was to characterize the genetic and phenotypic diversity of Rhizobium isolates associated with Phaseolus vulgaris from southern Ecuador. Morpho-cultural characterization, biochemical tests and physiological analyses were conducted to authenticate and determine the diversity of bacteria Rhizobium-like isolates. The genetic diversity of the isolates was determined by molecular techniques, which consisted of bacteria DNA extraction and amplification and sequencing of the 16S rRNA gene. The nodulation parameters and nitrogen fixation for P. vulgaris under greenhouse conditions were also assessed to determine the phenotypic diversity among isolates. Furthermore, bacteria indole-acetic-acid production was evaluated by the colorimetric method. Morpho-cultural and biochemical characteristic assessments demonstrated that Rhizobium-like bacteria was associated with the P. vulgaris nodules. The diversity among the isolates, as determined by physiological analyses, revealed the potential of several isolates to grow at different pH values, salinity conditions and temperatures. Partial sequencing of the 16S rRNA gene identified the Rhizobium genus in every sampling site. From a total of 20 aligned sequences, nine species of Rhizobium were identified. Nodule formation and biomass, as well as nitrogen fixation, showed an increase in plant phenotypic parameters, which could be influenced by IAA production, especially for the strains R. mesoamericanum NAM1 and R. leguminosarum bv. viciae COL6. These results demonstrated the efficiency of native symbiotic diazotrophic strains inoculants for legume production. This work can serve as the basis for additional studies of native Rhizobium strains and to help spread the use of biofertilizers in Ecuadorian fields.

Introduction. Quinoa (Chenopodium quinoa Willd.) is a strategic and important crop for food security and sovereignty. It is the only plant-based food that provides all essential amino acids. Its wide varietal diversity constitutes a valuable genetic resource, as it adapts to different agroecological conditions and is tolerant to frost, drought and salinity. Objective. To perform a morpho-agronomic characterization of native Chimborazo-type quinoa in Ecuador. Materials and Methods. The research was conducted in the province of Chimborazo, Colta canton, Sicalpa parish, Ocpote Tablarumi community in Ecuador between January and July 2021. Seeds from an Andean family that had selected and conserved them in all cultivation cycles for generations were used. The crop was established by continuous sowing at a rate of 12 kg/ha in a total plot area of 640 m2 (estimate to contain 10,240 plants). After the emergence, 100 randomly selected plants were marked and taken as basic units for the population characterization. Phenotypic descriptors established at international level were used, evaluating both qualitative (16) and quantitative (12) traits. Results. The results revealed phenotypic variability. Stem and streak color, panicle diameter, panicle length, and days to harvest were the characteristics that most contributed to the observed variability. Conclusions. The population of native Chimborazo-type quinoa evaluated through 100 individuals showed phenotypic variability in both quantitative and qualitative traits, with greater frequency observed in panicle diameter, panicle length, petiole length, plant height, leaf width, yield, and stem and streak color.