New rhizobia strains isolated from the Amazon region fix atmospheric nitrogen in symbiosis with cowpea and increase its yield

Abstract

Studies in the Amazon indicate a wide diversity of rhizobia with the ability for biological nitrogen fixation (BNF), which could expand the number of strains approved for cowpea. Thus, the aim of this field study was to evaluate the agronomic performance in cowpea of the several strains isolated from the soils of the Brazilian states Acre and Rondônia, and to compare them with strains approved by the Ministry of Agriculture (MAPA) and with non-inoculated controls (without and with mineral nitrogen fertilizer). The inoculants performed well. Though less effective than the other strains, the UFLA 03-36 strain also was prominent with respect to

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

“…Even numerous and competitive native soil bacterial populations are not always able to establish efficient symbiosis that significantly contributes to common bean growth. Thus, it may be necessary to employ inoculants containing strains that are more efficient in N 2 fixation (Ferreira et., 2009;Moreira, Siqueira & Brussaard, 2006;Oliveira et al, 2019;Oliveira, Ferreira, et al, 2018;Pádua Oliveira et al, 2017;Soares et al, 2006), such as those found in the present study (Tables 2 and 4; Figures 2, 3, and 4). The contribution of these populations rises, in turn, when complemented with 80 kg N-urea ha −1 (C7), that is, the increase in yield was due to the nitrogen fertilizer; however, C7 showed less stability than C6.…”

“…Studies in the Amazon have indicated a wide diversity of rhizobia with the ability to tolerate stresses predominant in tropical soils (Ferreira et al., 2012; Guimarães et al., 2012; Oliveira‐Longatti et al., 2013, 2014; Soares et al., 2014). Furthermore, Rhizobium strains isolated from the Brazilian Amazon region have shown the capacity for biological N 2 fixation with leguminous species (Costa et al., 2019; Ferreira et al., 2019; Guimarães et al., 2015; Nogueira et al., 2017; Oliveira et al., 2017, 2020; Oliveira, Ferreira, et al., 2018; Oliveira, Soares, et al., 2018; Oliveira‐Longatti et al., 2013; Pádua Oliveira et al., 2017; Soares et al., 2006; 2014; Zilli et, al.,2009) and, for that reason, have received special attention in studies directed to the production of inoculants. In addition, attention to inoculant production has increased due to the possible adverse effect of chemical fertilizers on the environment and their production costs.…”

Biological Nitrogen Fixation Stability of Cowpea Cultivars With Tropical Semi-Arid Rhizobial Strains

“…Although nodulation was not subject to an interaction between cultivar and isolate, SDM was, with different cultivars achieving better results with different rhizobial isolates. The highest SDM occurred for G7.85, IPA-206, and BR 17-Gurguéia, whereas BRS Novaera BR 3262 had a significantly higher SDM (Table 2), confirming the high potential of the latter strain (FERREIRA et al, 2019).…”

Diversidade e eficiência simbiótica de rizóbios de solos de clima semiárido tropical com diferentes fertilidades

“…O estabelecimento da simbiose com rizóbios de crescimento rápido e lento deve-se à baixa especificidade simbiótica do feijão-caupi. A nodulação do feijão-caupi é frequentemente estabelecida com isolados de crescimento lento em diversos ambientes (TAMPAKAKI et al, 2017;CHIDEBE et al, 2018;FERREIRA et al, 2019), porém a predominância de nodulação por rizóbios de crescimento rápido vem sendo cada vez mais observada (ONDIEKI et al, 2018;GIRIJA et al, 2018).…”

“…Estudos indicam que o fornecimento de N 2 pela simbiose de rizóbios e feijão-caupi varia de 15 a 99% da necessidade da leguminosa (NCUBE et al, 2007;NAAB;CHIMPHANGO;DAKORA 2009). Esta variação deve-se à diversidade funcional do isolados (JAISWAL; DAKORA, 2019) e boa capacidade de competição dos isolados selecionados por sítios de infecção nodular (Oliveira et al, 2017;Ferreira et al, 2019).…”