Agronomic efficiency of Rhizobium strains from the Amazon region in common bean

Abstract

To maximize the contribution of biological nitrogen fixation in common bean, it is necessary to use bacterial strains that are more adapted, competitive, and efficient in the symbiotic process. In this regard, the aim of this study was to evaluate the agronomic efficiency (AE) of three bacterial strains isolated from acid soils with high Al content from the Amazon region in an Argissolo Vermelho Distrófico típico soil (Typic Rhodustults -USDA Classification) from the municipality of Formiga, MG, Brazil. We compared their AE to that of the reference strain CIAT 899 T and of two controls without inoculation (one without and another with 80 kg ha -1 of N-urea). The results indicated that inoculation with the strains UFLA 02-100 and UFLA 02-127 provides grain yield equivalent to inoculation with the reference strain and to the control with mineral N. Thus, both have potential for recommendation as inoculants for common bean. KEYWORDS: Phaseolus vulgaris L., rhizobia, biological nitrogen fixation, seed inoculation Eficiência agronômica de estirpes de Rhizobium isoladas da Amazônia sobre o feijoeiro-comum RESUMOPara maximizar a contribuição da fixação biológica de nitrogênio no feijoeiro-comum é necessária a utilização de estirpes de bactérias mais adaptadas, competitivas e eficientes no processo simbiótico. Nesse sentido, objetivou-se avaliar, em um Argissolo Vermelho Distrófico típico do município de Formiga-MG, a eficiência agronômica (EA) de três estirpes isoladas de solos ácidos e com alto teor de Al da Amazônia e comparar suas EA à da estirpe referência CIAT 899 T e à de dois controles sem inoculação (um sem e outro com 80 kg ha -1 of N-ureia). Os resultados indicaram que a inoculação com as estirpes UFLA 02-100 e UFLA 02-127 propicia rendimento de grãos equivalente ao da estirpe referência e ao do controle com N mineral e que por isso, ambas têm potencial para ser recomendadas como inoculantes para o feijoeiro-comum. PALAVRAS CHAVE: Phaseolus vulgaris L., rizóbio, fixação biológica de nitrogênio, inoculação na semente

Acid tolerant Rhizobium strains contribute to increasing the yield and profitability of common bean in tropical soils

“…The strains UFLA 02-100, UFLA 02-68, UFLA 02-127, and UFLA 04-173 were collected from different environments and soils of the Amazon and have shown high effectiveness in biological nitrogen fixation in common bean, as well as high tolerance to acidity and high Al concentration (Ferreira et al, 2009;2012;Rufini et al, 2011;Oliveira-Longatti et al, 2013;Nogueira et al, 2017 Table 2. Origin, characteristics, and identification of the Rhizobium strains used as inoculants for common bean (Phaseolus vulgaris L.) in the study.…”

“…In this respect, studies have been undertaken, showing good results in the field not only with the strain CIAT 899 of Rhizobium tropici, whose symbiotic efficiency is already well known (Graham et al, 1994), but also with strains isolated from acid soils with high Al content from the Amazon (Soares et al, 2006;Ferreira et al, 2009;Nogueira et al, 2017). Studies in regard to the economic viability of inoculation with Rhizobium in common bean, however, are few, but they could assist in choosing the strain to be adopted.…”

Selection of elite Rhizobium strains by biometric techniques for inoculation in common bean

“…The strain UFLA02-127 (S5), just as the others of the UFLA code studied here, was isolated from acid soils of the Brazilian Amazon and also belongs to the Rhizobium genus. It is tolerant to acidity, has high ability in competition with already established strains, and has high N 2 fixation capacity (Nogueira et al, 2017;Oliveira, Ferreira, et al, 2018;Pádua Oliveira et al, 2017;Soares et al, 2006). Furthermore, It has performance comparable to that of CIAT899 in peat (Nogueira et al, 2017;Pádua Oliveira et al, 2017) and liquid (Oliveira, Ferreira, et al, 2018) vehicles, which increases its chance of being adopted by farmers.…”

“…They were isolated from acid soils with high Al content from the Brazilian Amazon; high acidity and high Al content stresses predominate in tropical soils. In addition to tolerance to acidity, the strains have high competitive ability with the already established strains and high N 2 fixation capacity (Nogueira et al., 2017; Soares et al., 2006, as described in Oliveira, Soares, et al., 2018; Pádua Oliveira et al., 2017). The C6 genotype was considered a control treatment because it consisted of native strains from the environments tested.…”

“…The growth capacity of the UFLA02-100 (S2) strain under high (pH 4.9-5.0: Soares et al, 2006;Rufini et al, 2011), moderate (pH 5.6-6.0: Rufini et al, 2011;Nogueira et al, 2017;Oliveira, Ferreira, et al, 2018;Pádua Oliveira et al, 2017), and low (pH 6.4: Pádua Oliveira et al, 2017) active acidity provides conditions for adaptation to different environments, even though conditions for its development appear to be optimal since it had variable performance in this study, above all in E2 and E7, which affected the GE interaction. Even so, its yield remained at around 1,200 kg grain ha −1 in the varied environments (Table 1).…”