Studies on Zinc Solubilizing Bacteria and Their Effect on Growth and Yield of Maize (Zea Mays L.)
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Date
2013
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UAS, Dharwad
Abstract
Attempts were made to isolate zinc solubilizing bacteria from rhizosphere soil of
different crops from Dharwad and Belgaum districts. A total of 30 bacteria isolates were
tested for Zn solubilization and characterized upto genus level based on morphological and
biochemical characters. The mechanisms involved in Zn soluiblization and other agronomical
beneficial traits were also analyzed for selected efficient strains.
In vitro Zn solubilization by bacteria ranged from 5.57 ppm to 13.57 ppm. Gluconic
acid was the main organic acid produced by the ZSB isolates. Thirteen isolates were tested
for other beneficial traits like production of organic acid, production of siderophore and
production of growth promoting substance. All the thirteen isolates produced gluconic acid.
The amount of siderophore produced by the strains ranged from 0.35 to 0.91 μg/ml. The
amount of IAA and GA produced by the strains ranged from 5.43 to 10.67 and 1.07 to 2.77
μg/ 25 ml respectively.
Two efficient gram negative Zn soluiblizing bacteria were also examined for their
influence on growth and yield of maize plants under glass house condition. All the treatment
with combined inoculation of ZSB-1 and ZSB-2 were found to increase growth parameters,
nutrient content and yield components compared to control and with single inoculation of
ZSB. The treatment T16 (ZSB-1 + ZSB-2 + RD of NPK + 100% Zn) recorded the highest
yield (75.70 g/plant) and other parameters followed by T15 and T14 (73.5 and 71.7 g/plant
respectively). Population of ZSB, PSB, N2 fixers and dehydrogenase activity in rhizosphere
soil of maize were significantly higher in the treatment inoculated with ZSB-1 + ZSB-2 as
compared to control and single inoculation. Thus it can be inferred that combined inoculation
of zinc solubilizing bacteria have the potential to be use as bioinoculants