Genetic Interaction Studies Reveal Superior Performance of Rhizobium tropici CIAT899 on a Range of Diverse East African Common Bean (Phaseolus vulgaris L.) Genotypes

Abstract

The existence of genotype-by-strain (GL × GR) interaction has implications for the expected stability of performance of legume inoculants and could represent both challenges and opportunities for improvement of nitrogen fixation. We find that significant genotype-by-strain interaction exists in common bean (Phaseolus vulgaris L.) but that the strength and direction of this interaction depends on the growing environment used to evaluate biomass. Strong genotype and strain main effects, combined with a lack of predictable patterns in GL × GR, suggests that at best individual bean genotypes and strains can be selected for superior additive performance. The observation that the screening environment may affect experimental outcome of GL × GR means that identified patterns should be corroborated under more realistic conditions.

Symbiotic interactions between chickpea (Cicer arietinum L.) genotypes and Mesorhizobium strains

“…Subsequently, the local strains were phylogenetically characterized following the protocols we adopted previously (Gunnabo et al 2019). Accordingly, partial 16S rRNA, gyrB, recA and rpoB housekeeping genes and symbiotic genes nifH and nodC were directly amplified from colony suspensions using a PCR (Bio-Rad Company).…”

“…The edited sequences were compared to GenBank database using the online nucleotide BLAST method (https://blast.ncbi.nlm.nih.gov/) to check if the right gene is sequenced and to which Mesorhizobium species it belongs. Multiple nucleotide sequence alignments were carried out using the CLUSTAL W program and concatenated in R 3.6.1 as we described previously (Gunnabo et al 2019). The estimates of the bestfit models under maximum likelihood (ML) criterion for Where: HwU is Hawassa University; C. = Cicer; A. fruticosa = Amorpha fruticosa; A. sinicus = Astragalus sinicus; "√" = strains tested either in pots or jars; "X" strains that were not tested in the pot experiment…”

“…Since there was germination problem of Kabuli genotypes in the jar experiment as indicated above, some of the genotypes were rejected and only those that had at least three successful replications (subset of genotypes) were considered. The selected genotypes and strains (Tables 1 and 2) and their factorial combinations along with positive and negative controls (as described above) were tested in a pot experiment following the same protocols and growth conditions described in our previous work (Gunnabo et al 2019).…”

Selection of elite Bradyrhizobium strains by biometric techniques for inoculation in cowpea

“…Biometric techniques are widely applied to plant breeding for analysis and interpretation of genotype response under environmental interactions, without restrictions for use in microbiological studies. In spite of this possibility, only application of the AMMI modeling is found in the literature associated with study of the interaction of N 2 -fixing bacterial strains in pots with a sterile solution (Gunnabo et al, 2019). It is encouraging to study the G×E interaction with grain yield results in the field, above all in Brazil, where there is high heterogeneity of soils and climate conditions.…”

“…The use of these techniques is widespread in studies on plant species and many other commercial crops (Borges et al, 2010;Breseghello et al, 2011;Carbonell et al, 2007;Freiria et al, 2018). In microbiological studies, almost no reports have this focus (Gunnabo et al, 2019). However, these same methods could be applied in the selection of microorganisms of agricultural importance because they are based on the effects on plant production in edaphic and climatic environments.…”