Rhizobium strains competitiveness on bean nodulation in Cerrado soils

Ruy Raposeiras,Lilia Costa Carvalhais,Israel Alexandre Pereira Filho,Patrícia Pereira Pinto,Raul Vinícius Magalhães Passos,Ivanildo Evódio Marriel,Edilson Paiva,Maria Rita Scotti Muzzi,Nadja Maria Horta De Sá

doi:10.1590/s0100-204x2006000300010

Ruy Raposeiras, Lilia Costa Carvalhais + Show 7 more

Open Access

https://doi.org/10.1590/s0100-204x2006000300010

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Abstract

The objective of this work was to identify the most competitive and effective Rhizobium strains in order to increase common bean yield by nitrogen fixation as alternative or complementation to the nitrogen fertilization. Competitiveness tests were lead in axenic conditions, in Cerrado soil pots and in three field experiments, with native Rhizobium strains that were previously identified, according to their effectiveness and genetic variability. The identification of strains in nodules was performed using serological tests (axenic conditions) - agglutination and enzyme linked immunosorbent (Elisa) assays - and random amplified polymorfic DNA (RAPD) (Cerrado soil). Plant yield was determined using the dry weight (greenhouse conditions), total N and grain yield (field experiments). Among the analyzed Rhizobium strains, native strain SLA 2.2 and commercial strain CIAT 899 were the dominant nodules in plants of the most productive plots, presenting yield productivity similar or higher to those obtained in treatments where 20 kg ha-1 of N were applied.

Highlights

Common bean (Phaseolus vulgaris L.) is one of the most traditional crops in Brazil and very expressive in “Cerrados”, an edaphic type of savanna in the central region of the country
Tropical soils present a high number of these rhizobial strains, but they are considered of low efficiency (Pereira et al, 1991)
The objective of this work was to evaluate competitiveness of efficient bean nodulating strains of Rhizobium isolated from Cerrado soils employing agglutination, enzyme linked immunosorbent assay (Elisa) and random amplified polymorfic DNA (RAPD) (Random amplified polymorphic DNA) methods of identification

Summary

Introduction

Common bean (Phaseolus vulgaris L.) is one of the most traditional crops in Brazil and very expressive in “Cerrados”, an edaphic type of savanna in the central region of the country. Yield is very low, due to poor cropping practices, such as an inefficient supply of fertilizer, especially nitrogen (N). Biological nitrogen fixation (BNF) by rhizobia can supply partly or all. Bean plants are considered very promiscuous, nodulating with various fast growing Rhizobium such as R. leguminosarum bv. Phaseoli (Jordan, 1984), R. tropici (Martinez-Romero et al, l991), R. etli (Segovia et al, 1993), R. gallicum and R. giardini (Amarger et al, 1997). Tropical soils present a high number of these rhizobial strains, but they are considered of low efficiency (Pereira et al, 1991).

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