Selection of Rhizobium leguminosarum bv. viceae strains for inoculation of Pisum sativum L. cultivars: Analysis of symbiotic efficiency and nodulation competitiveness

Abstract

From an analysis of 481 Rhizobium leguminosarum bv. viceae strains with 7 pea cultivars in pot and field experiments, we demonstrated that effective strains could be isolated from a rich medium-acid grey forest soil of the Or61 area (Central region of the European part of Russia) but not from a poor acid podzolic soil of the St. Petersburg area (North-West Russia). The proportion of the isolates significantly increasing N accumulation in pea plants (10.2%) is higher than that of strains increasing the shoot dry mass (4.6%) in the pot experiments. The mean values of the increase for N accumulation (33.8%) upon inoculation are also higher than for shoot mass (27.0%) in these experiments. N accumulation in the inoculated pea plants in the pot experiments was significantly correlated with seed yield and seed N accumulation in field experiments, while for shoot dry mass these correlations were either weak or not significant. Two-factor analysis of variance demonstrated that the contribution of plant cultivars to the variation of the major symbiotic efficiency parameters is higher (30.8-31.6%) and contributions of cultivar-strain specificity is lower (5.4-8.8%) than the contributions of strain genotypes (13.4-14.9%). We identified an ineffective R. leguminosarum bv. viceae strain 50 which can be used as a tester for assessing the nodulation competitiveness of the effective strains by an indirect method (analysis of dry mass and N accumulation in pea plants inoculated with the mixture of the tested effective strains and the tester strain). The relative competitive ability (RCA) determined by this method was 75.7-82.8% for strain 52 but only 10.5-13.8% for strain 250a; this difference was confirmed by a direct method (use of the streptomycin-resistant mutants). Results of screening of the diverse collection of 53 effective R. leguminosarum bv. viceae strains by the indirect method permits us to divide them into 3 groups (32 high-competitive, 10 medium-competitive and 11 low-competitive strains) but reveals no correlation between the competitiveness and symbiotic efficiency. N accumulation in the pea shoots is demonstrated to be a much more suitable criterion than the shoot mass for selection either of the highly-effective or of highly-competitive (by the indirect estimation) R. leguminosarum by. viceae strains in the pot experiments.

Indigenous rhizobia population influences the effectiveness of Rhizobium inoculation and need of inorganic N for common bean (Phaseolus vulgaris L.) production in eastern Ethiopia

“…In those with medium rhizobial population, a positive and strong correlation between PTTN and SDW (r = 0.7665; P ≤ 0.01), NPP (r = 8386; P ≤ 0.01), NSP (r = 0.7154; P ≤ 0.01), 100 seed weight (r = 0.5206; P ≤ 0.05), TBY (r = 0.9114; P ≤ 0.001) and GY (r = 0.6941; P ≤ 0.05) ( Table 6). These results agree with the previous studies, which reported the significant correlation between plant N accumulation with seed yield, seed weight and total biomass [45,50]. Ruiz-Díez et al [45] also demonstrated that plant N accumulation was the most suitable trait for the selection of highly effective and highly competitive Rhizobium ), SDW shoot dry weight (g plant…”

“…Asad et al [15] observed that nodulation improvement due to inoculation had not significantly enhanced plant biomass production. This present study also confirms that the common bean-rhizobia symbiosis was not satisfactory to fulfill the N needs as it has been previously observed by Fesonko et al [50]. Contrary to this, Denton et al [40] showed that improvement of shoot N increased the grain yield of faba bean by 1 Mg ha −1 in soil having low rhizobial population.…”

Host‐specific competitiveness to form nodules in Rhizobium leguminosarum symbiovar viciae

“…Nevertheless, BNF may be suboptimal because of the presence of poorly effective but highly competitive Rlv that outcompete BNF-efficient compatible bacteria (Laguerre et al, 2003). Despite the potential interest for inoculation of pea with effective Rlv strains (Bremer et al, 1988;Fesenko et al, 1995;McKenzie et al, 2001), inoculant strains are frequently outcompeted by naturally occurring ineffective rhizobia (Meade et al, 1985). Understanding the determinants of CFN will allow the selection of bacteria for improved inoculation strategies (Triplett & Sadowsky, 1992;Laguerre et al, 2003).…”

Co-inoculation of a Pea Core-Collection with Diverse Rhizobial Strains Shows Competitiveness for Nodulation and Efficiency of Nitrogen Fixation Are Distinct traits in the Interaction

“…In the complex soil environment, legume roots are exposed to heterogeneous rhizobial populations containing multiple compatible strains (Laguerre et al, 2003 ; Mutch and Young, 2004 ; Bourion et al, 2007 ; Sachs et al, 2009 ). Various data indicate that BNF could be suboptimal in pea as natural Rlv populations are quantitatively and qualitatively heterogeneous, which often results in nodulation of peas by poorly efficient rhizobia (Fesenko et al, 1995 ; Laguerre et al, 2007 ). There is general agreement about the interest of rhizobial inoculation of pea with selected Rlv bacteria for improving BNF (Bremer et al, 1988 ; Fesenko et al, 1995 ; McKenzie et al, 2001 ).…”