INVESTIGADORES
GIORDANO Walter Fabian
congresos y reuniones científicas
Título:
Co inoculated treatment with native and reference Bradyrhizobium: alternative to enhance peanut yields
Autor/es:
VICARIO J.C., PRIMO E.D., GIORDANO W.F., AND DARDANELLI M.S.
Lugar:
La Falda
Reunión:
Workshop; II Workshop latinoamericano sobre rizobacterias promotoras del desarrollo vegetal; 2014
Resumen:
Introduction
Inoculation of peanuts has
yielded controversial results and is a discussed agricultural practice. The
application of the appropriate strain of rhizobia, can produce a higher yield
of fruits with high protein content. This refers to the relative ability of
particular strains to occupy nodules on host plants in the presence of other
symbionts. The soils of the groundnut area are characterized by a native
population of rhizobia able to nodulate peanut, which is not always
sufficiently effective. The optimization in the process of nitrogen fixation
should be achieved with the use of a strain according to the host which is
accomplished with studies related to its ability to colonize, competition,
efficiency in fixing, among other features. Bacteria of the family Rhizobiaceae
interact with leguminous plants in a host-specific manner and form N2-fixing
root nodules. On the other hand, bacteria of the genus Azospirillum are free-living, surface colonizing, sometimes
endophytic diazotroph and plant growth promoting rhizobacteria (PGPR). They are
capable of increasing the yield of important crops growing in various soils and
climatic regions.
Objective
The aim
of this research was to study the effect of co-inoculation of recommended and
indigenous bradyrhizobia and a PGPR (Azospirillum
brasilense Az39) on nodulation and symbiotic performance of peanut.
Materials and methods
Treatments tested in the in vitro assays were: simple
inoculations with Bradyrhizobium
strains (C145, SEMIA6144, USDA4438, 15A, PC34), Azospirillum brasilense Az39 and co-inoculated Bradyrhizobium-Azospirillum brasilense Az39. They were inoculated at the time of transferring the
pregerminated seeds with A. brasilense Az39 at 1x106 CFU/ml and rhizobial strains 1x109
CFU/ml. Six parameters were determined in
each trial: length and dry weight of stem and root, number of nodules/plant and dry weight estimated inmg/plant root nodules.
The field trial was
performed according to the described by Boginoet al. (2006). The treatments tested
were: co-inoculated Bradyrhizobium
(C145, 15A and Pc34)-A. brasilense Az39.
Results
The maximum values of stem and root length were observed in the co-inoculated treatments. A similarbehavior was observed in the dry weightsof roots and stems. The number and dry weight of nodules was increased whenco-inoculate withAz39; obtaining maximum values the native strains 15A, Pc34 and the reference strain USDA4438. The behavior of the native strains in the field proved to be variable, the 15A strain showed the
best performance in all measured
variables: stem dry weight,
number of boxes, number and dry weight of nodules, beating C145 strain recommended by INTA (Instituto Nacional de Tecnología Agropecuaria).
Conclusion
A general positive effect was observed in the presence
of Azospirillum. Co-inoculation with
native bradyrhizobia (15A and Pc34) and A.
brasilense Az39 caused a significant increase in the overall number and dry
weight of nodules per plant being equals or mayors to those obtained by the
reference strains.
In assessing the behaviour of native strains in the
field in contrast to C145, 15A scored the best test results, demonstrating that the selection of native strainsadapted to groundnut soils can be a strategy for the development of new products to obtain better yields of peanut.