Rhizobium inoculants for alfalfa in acid soils

A proposal for Uruguay

  • Sofía Tabares-da Rosa Laboratorio de Bioquímica, Depto. Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay. https://orcid.org/0000-0003-2251-3432
  • Santiago Signorelli Laboratorio de Bioquímica, Depto. Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay https://orcid.org/0000-0002-1854-3164
  • María Florencia Del Papa Instituto de Bioquímica y Biología Molecular, Facultad de Ciencias Exactas, Universidad de la Plata, Argentina https://orcid.org/0000-0003-0088-6756
  • Ornella Sabatini Laboratorio de Bioquímica, Depto. Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay. https://orcid.org/0000-0003-3351-4692
  • Rafael Reyno Instituto Nacional de Investigación Agropecuaria, INIA La Estanzuela e INIA Tacuarembó, Uruguay https://orcid.org/0000-0001-9619-8477
  • Fernando Lattanzi Instituto Nacional de Investigación Agropecuaria, INIA La Estanzuela e INIA Tacuarembó, Uruguay https://orcid.org/0000-0002-2682-3692
  • Mónica Rebuffo Instituto Nacional de Investigación Agropecuaria, INIA La Estanzuela e INIA Tacuarembó, Uruguay https://orcid.org/0000-0003-0044-4771
  • Juan Sanjuán Depto. de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain https://orcid.org/0000-0002-6404-8754
  • Jorge Monza Galetti Laboratorio de Bioquímica, Depto. Biología Vegetal, Facultad de Agronomía, Universidad de la República, Uruguay.Facultad de Agronomía https://orcid.org/0000-0002-4309-7397
Keywords: Ensifer meliloti, Oregon strains, available aluminium

Abstract

Ensifer meliloti establishes symbiosis with Medicago sativa (alfalfa) and other perennial species of Medicago that grow in soils with neutral to alkaline pH, whereas Ensifer medicae makes symbiosis with annual medics adapted to moderately acid soils. The new species Rhizobium favelukesii, whose strain is LPU83, belongs to an alfalfa group of inefficient rhizobia, known as the Oregon type, initially represented by Rhizobium sp. strain Or191. R. favelukesii is considered a potential risk in the acid soils where alfalfa is grown, and could explain the inefficient nodulation observed in different countries. In acidic soils from the «Dairy Basin» of Uruguay, producers inoculate alfalfa with E. melliloti U143 strain. This edaphic condition is often marginal because the maximum potential of rhizobia-alfalfa symbiosis is not achieved at acid pH. Although Uruguay has an outstanding position in the production and use of rhizobial inoculants, the commercial strains currently used in Trifolium, Lotus and alfalfa were selected about 50 years ago in different conditions that the present ones as a consequence of: i) the displacement of cultivated pastures to other sites, ii) the sowing method, and iii) the use of new cultivars. In this review, alfalfa inoculation is analyzed in some countries and a strategy for the development of an inoculant suitable for Uruguayan acid soils is proposed. This strategy is based on the selection of efficient and competitive strains, as the first selection criteria, and persistency in soil as the second one.

Published
2019-11-01
How to Cite
1.
Tabares-da Rosa S, Signorelli S, Del Papa M, Sabatini O, Reyno R, Lattanzi F, Rebuffo M, Sanjuán J, Monza Galetti J. Rhizobium inoculants for alfalfa in acid soils. Agrociencia Uruguay [Internet]. 1Nov.2019 [cited 9Apr.2020];23(2):1-13. Available from: http://agrocienciauruguay.uy/ojs/index.php/agrociencia/article/view/120
Section
Plant and microbial biotechnology