SOYBEAN RESEARCH

did not differ significantly. On the other
hand, irrespective of soil conditions,
plants inoculated with AMF alone or
with Bradyrhizobium at 50 per cent RDF
produced comparatively higher
nodulation and grain yield than other
treatment combinations and was found
significantly higher over control plants.
However, these plants produced
statistically similar response to RDF
plants. This indicated that both the
strains of rhizobia are compatible with
AMF for producing higher nodulation
and yield response.
Under field conditions, dual
inoculation of AMF and Bradyrhizobium
with and without 50 per cent RDF had
significantly higher nodule dry mass as
compared to other treatments. However,
the nodule number was not influenced by
inoculation treatments (Fig. 3).
Significantly higher grain yield was
recorded in treatment comprising of 50
per cent RDF with dual inoculation over
control and did not significantly vary
with treatments comprising of AMF
application alone or with 50 per cent RDF
(Fig. 3).
The present findings of higher
response of AMF and Bradyrhizobium as
dual inoculation is corroborated
(Meghvansi et al., 2008), wherein they
found that dual inoculation with AMF (G.
intraradices) and Bradyrhizium japonicum
improved nodulation, growth parameters
demonstrating synergism between the
two microsymbionts. Among the dual
treatments, G. intraradices and B.
japonicum brought about significant
increases in the studied characteristics
particularly in seed weight per plant,
which increased up to 115.19 per cent,
suggesting a strong selective synergistic
relationship existed between AMF and B.
japonicum. It is attributed that soybeanbradyrhizobia
association in the study
benefited from AM fungi due
development of extended root and
hyphal network which not only met P
demand but also helped plants to
ameliorate any other nutrient deficiencies
might be limiting to bradyrhobia (Smith,
2002). For example Wang et al. (2011)
demonstrated the co-inoculation
responses in deep rooted soybean
genotypes for higher uptakes of N and P.
Increased mineral nutrient levels in the
plants would not only benefit rhizobia
directly, but would also lead to increased
photosynthesis, making a greater
proportion of photosynthates available to
the Rhizobium nodules (Mortimer et al.,
2008). Very recently Meng et al. (2015)
demonstrated the inoculation of both
AMF and rhizobium in the soybean +
maize intercropping system which
improved the N-fixation efficiency in
soybean and promoted N transfer from
soybean to maize, resulting in the
improvement of yield advantages of
legume + non-legume intercropping. In
our study, inoculated plants had
significantly higher nitrogen uptake in
roots and nodules as compared to
uninoculated plants (Fig. 1). However,
comparatively higher N-uptake was
observed in plants inoculated with AMF
and Bradyrhizobium alone or with 50 per
cent RDF. Besides enhancing N-uptake
and yield, the treatments consisting of
dual inoculation of AMF and rhizobia
alone and with 50 per cent RDF did
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