Page 56 - BJS vol. 36

Bangladesh J. Sugarcane, 36 : 48-58 June, 2015

Isolation and Characterization of Diazotrophic Bacteria and
Its Effects on Growth and Yield of Sugarcane

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K.M. Alam *, S. Islam , M.S. Islam , M.A. Haque , A.S. Mitu , M.S. Rahman and
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G.M.A. Hossain
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Station Incharge, BSRI Sub-station, Joypurhat
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Soils and Nutrition Division, Agronomy and Farming Systems Division
Bangladesh Sugarcrop Research Institute, Ishurdi-6620, Pabna, Bangladesh
ABSTRACT
The study was conducted both in the laboratory and field at
Bangladesh Sugarcrop Research Institute during 2013-2014 cropping year.
Two diazotrophic bacterial strains were isolated from the surface sterilized
stems of sugarcane. The study was aimed to isolate endophytic nitrogen-fixing
bacteria and to assess its performances on the growth and yield of sugarcane.
The two species were characterized based on 16S rRNA gene sequences
named as Pantoea agglomerance and Klebsiella pneumoniae. Nitrogen fixing
ability was verified by the acetylene reduction assay that was found 6.98 to
7.60 nmole C 2H 4/ml/h. The highest indole acetic acid production was found in
Klebsiella pneumoniae, which was 62.0µg/ml. A field experiment was carried
out with six treatments viz., T 1 = No fertilizers and bacterial strains, T 2 =
Recommended Dose of Fertilizers (RFD), T 3 = 50% N of RFD + Klebsiella
pneumoniae, T 4 = 50% N of RFD + Pantoea agglomerans, T 5 = 75% N of RFD
+ Klebsiella pneumoniae, T 6 = 75% N of RFD + Pantoea agglomerans and two
sugarcane varieties Isd 37 and Isd 39. The variety Isd 37 showed the highest
germination, Brix per cent and yield in sugarcane. The highest pol per cent was
found in T 5 (10.84%) where 75 % N of RFD + Klebsiella pneumoniae was
applied. Considering the interaction effect, it was found that V 1T 5 produced the
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highest yield of cane (99.26 tha ) where 75 % N of RFD + Klebsiella
pneumoniae was applied in the variety Isd 37. Thus it revealed that N 124
P 55K 120S 30Zn 2.5Mg 10B 1.5 + Klebsiella pneumoniae was found the best treatment
combination of nitrogen-fixing bacteria and inorganic fertilizer for higher
sugarcane yield.

Key words: Sugarcane, diazotrophs, yield, nitrogen fixation
INTRODUCTION

Sugarcane is a long duration and exhaustive sugar crop, providing over 76% of
the sugar for human consumption. An estimated N requirement of sugarcane in
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Bangladesh is about 165 Kg N ha . The use of elevated doses of fertilizer may have
negative and unpredictable effects on the environment, and contribute to the
contamination of soil, water and natural areas. Such impacts pose a serious threat to
human and animal health. In addition, developing countries have to face the demand of
high costs for such technology and chemical utilization. An interesting option for
decreasing the use of chemical fertilizers could be the exploitation of nitrogen fixing
bacteria. Several nitrogen fixing bacteria such as Enterobacter cloacae, Bacillus

* Corresponding author: K.M. Alam, Senior Scientific Officer
e-mail: mohiulalam74@yahoo.com