Synergistic effect of Mesorhizobium and non rhizobial endophytes on plant growth promotion in chickpea (Cicer arietinum L.)
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Date
2018
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Punjab Agricultural University, Ludhiana
Abstract
The present investigation was carried out to exploit non rhizobial endophytic bacteria from
root and nodules of chickpea. Of 263 non rhizobial endophytic bacteria 74.4 %, 87.4%,
12.6%, 36.6%, 37.4% and 55.7% were found to be positive for catalase, oxidase, citrate
utilization, nitrate reduction, methyl red and Voges Proskauer‟s, respectively. 71 were found
to be good for phosphate solubilization and IAA production. Significantly high P
solubilization was observed in root isolate RBR20 (20.60 mg100ml-1) whereas, among
nodule‟s isolates with RBN17 (21.0 mg100ml-1). In the presence of tryptophan, the isolate
LCRE 9 produced the maximum amount of IAA (39.60 μgml-1) whereas in the absence of
tryptophan the isolate RBR164 produced the maximum amount of IAA (19.93 μgml-1).
RBN16 isolate showed highest growth in DF medium with ACC (OD 1.04) followed by
RBR164 (OD 0.9985). High amount of GA production was observed in RBR19, RBR127,
RBR136, RBR164 and LCNE6 (112.15 μgml-1). Highest amount of EPS production was
observed LCRE8 (105.01 μgml-1). Out of 75 isolates 38.7%, 82.7%, 9.3% and 21.3% isolates
were able to produce cellulase, protease, HCN and fluorescent pigment, respectively. On the
basis of overall PGP traits and compatibility studies 3 potential non rhizobial endophytic
bacteria (RBR164, LCRE9 and RBN17) were selected for colonization study in different
combinations with ampicillin (6μgml-1) an antibiotic marker. Colonization was maximum in
RB1+LGR33+ RBN164 treatment (1.16 and 1.60) at 15th and 50th respectively. Triple
inoculant treatment LGR33+RB1+RBR164 resulted into maximum increase in plant height,
dry weight of shoot and total bacterial count at 90 DAS as compared to dual, single and
uninoculated control under field conditions. Maximum increase in dry weight of root, root
shoot ratio, nodule dry weight and leghaemoglobin was observed with same treatment at 60
and 90 DAS. Similar trend was observed for total NPK content of shoot and seed. Grain yield
was increased with triple inoculants treatment LGR33+RB1+RBR164 by 8.9% and 3.6% over
uninoculated control and recommended consortium of chickpea, respectively. It seems from
the foregoing study that consortium of Mesorhizobium with multifarious plant growth
promoting endophytic bacteria can be developed and used as biofertilizer for chickpea.
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