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Diazotropic bacteria from rice rhizosphere and their use as bioinoculants

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Title Diazotropic bacteria from rice rhizosphere and their use as bioinoculants
 
Creator Eriyagama, A.M.K.Indra
 
Contributor Sharma, P.K.
 
Subject Planting, Fungi, Application methods, Vegetative propagation, Rice, Inorganic acid salts, Biological development, Biological phenomena, Enzymes, Proteins
 
Description Rice is the world’s leading food crop and more consumed in the Asian region.
Microorganisms play an important role in soil health and crop productivity by
fixing nitrogen, solubilizing phosphate, secreting plant growth promoting
substances and suppressing the plant pathogens. The present investigation was
carried out to isolation and identification of efficient nitrogen fixing bacteria
from the rice rhizosphere and evaluate efficient nitrogen fixing bacteria as rice
inoculants. To meet the above objectives, following experiments were
conducted.
Eleven soil samples were collected from rice growing area of Haryana
from 7 locations. Soil samples were analysed for chemical properties pH, EC,
total N, available P, available K, organic C and microbial population. The pH of
the soil varied from 7.1 to 7.6 and electrical conductivity was in the range of 0.14 to
0.99 dSm-1. The organic carbon vried from 0.15 to 0.60 per cent. Available P and K
were varied from 7 to 12 and 72 to 312 mg kg-1 respectively.
Microbial population estimated for total bacteria, Azotobacer and
diazotrophic bacteria using nutrient agar, nitrogen free Jensen’s medium and
malate medium. Total bacterial count was in the range of 7.6 to 8.5 log CFU
g-1. Azotobacter count varied from 4.2 to 5.0 log CFU g-1. The diazotrophic
bacterial count varied from 5.5 to 6.4 log CFU g-1. Seventy four isolations
were made on nutrient agar and malate medium and 30 isolations were made on
Jensen’s medium.
All the isolates were tested for nitrogen fixation (ARA) and indole acetic
acid (IAA) production. The highest ARA among the isolates from NA medium
was shown by isolate IRN6 (78.7 n mole acetylene reduced h-1 tube-1). Among
the isolates from Jensen medium isolate IRJ2 showed maximum ARA (16.0 n
mole acetylene reduced h-1 tube-1). Eight isolates which showed higher ARA
and IAA, higher ARA and lower IAA and higher IAA and lower ARA were
selected for further studies. These isolates were IRN6, IRN10, IRN44, IRN45,
IRN55, IRJ2, IRJ18 and IRJ27.
Selected isolates were tested for rice seedling growth. Inoculation of
selected isolates improved the rice seedling growth by increasing root, shoot
length and root number over uninoculated control. Isolate IRN6 performed
better than other isolates and its inoculation showed more number of roots and
maximum increase in root and shoot length over the uninoculated control.
A pot experiment was conducted to see the effect of inoculation of
selected isolates on rice straw yield and grain yield at 75 and 100 per cent RDF.
The root ARA was measured in 75 d old plant after transplanting. Inoculation
with selected isolates increased the root ARA significantly and the
noninoculated control with no fertilizer. Application of nitrogen had strong
inhibitory effect on root ARA was observed. Significant increases in grain yield,
strain yield and root dry weight were observed with inoculation of selected
isolates, Mac 27 and Biomix over uninoculated control at 0 per cent RDF.
Similarly significant increase were observed in grain yield, straw yield and root
dry weight with inoculated selected isolates, Mac27 and Biomix at 75% RDF.
At 100% RDF significant increases in grain yield over uninoculated
control was observed in IRN6, IRN10, IRN44, Irn45, IRJ27 and Mac27. But it
is significantly highest in IRN6. Straw yield was significantly increases
observed in IRN6, IRN45, IRN55 and IRJ18. Highest significant increases
observed in IRN6. Root dry weight was significantly increases observed in
IRN6, IRN10, IRN44, IRN55, Mac27 and Biomix. Highest significant increases
observed in Mac27.
Rice straw, total nitrogen, soil total N and soil total P were improved the
inoculation with selected isolates over uninoculated control. Soil microbial
population increased the inoculation with selected isolates over uninoculated
control.
 
Date 2016-11-24T08:54:13Z
2016-11-24T08:54:13Z
2007
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/87324
 
Language en
 
Format application/pdf
 
Publisher CCSHAU