Characterization of phyllospheric bacteria for growth promotion of potato (Solanum tuberosum L.)
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Date
2017
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CCSHAU
Abstract
A total of forty six bacterial isolates were isolated from phyllosphere of five different crops
(Cotton, Mung bean, Potato, Wheat, and Pearl millet). All the bacterial isolates were characterized for
IAA production, Ammonia excretion, Antifungal activity, Nitrate reductase and Phosphate
solubilization. All the isolates were producing IAA and highest IAA produced by isolate WHK2 (31.06
μg/ml). All the 46 isolates were capable of excreting ammonia and highest ammonia excretion was
observed in isolate PMK3 (5.29 μg/ml). Out of 46 isolates, only 17 isolates showed antifungal activity
against A. niger and R. solani. All the 46 isolates showed nitrate reductase activity and highest nitrate
reductase activity was observed in isolate MUK1 (148.63 μg nitrite ml-1). A total of 15 bacterial
isolates solubilized phosphate and highest phosphate solubilisation index was observed in isolate COJ4
(19.18). On the basis of plant growth promoting traits, total 7 isolates (POK3, PMK3, COJ4, MUK1,
WHK2, WHN1 and WHN2) were selected for the pot house studies in potato (Kufri bahar var.).
Different parameter such as total viable count of bacteria in phyllosphere, chlorophyll a & b content,
ROS scavenging enzymes like superoxide dismutase, catalase and peroxidase were observed at
different interval of time. Potato yield & its plant height were observed at 90 days after showing. Total
phyllospheric viable count was maximum observed in foliar application of isolate PMK3 along with
RDF i.e. treatment T15 (7.8 log no. cfu/g leaves) at 90 DAS. Maximum chlorophyll a content (1.80
mg/g fresh weight) and chlorophyll b content (1.38 mg/g fresh weight) was observed in isolate COJ4
along with RDF i.e. treatment T19 at 60 DAS. No fixed trend of any phyllospheric bacteria were
observed on ROS activity in potato under pot house conditions. However maximum catalase ( 0.24 &
0.22 U/g fresh weight) observed in T4 Azotobacter chroococcum Mac27 (tuber treatment) along with
75% RDF at 30 and 60 DAS, maximum peroxidase (12.67 U/g fresh weight) observed in treatment T3
i.e. control RDF at 30 DAS and treatment T14 isolate PMK3 along with 75% RDF (12.52 U/g fresh
weight) at 60 DAS, maximum superoxide dismutase (481.80 U/g fresh weight) observed in treatment
T18 isolate COJ4 along with 75% RDF at 30 DAS and treatment T7 Azotobacter chroococcum Mac27
along with RDF (408.85 U/g fresh weight) at 60 DAS. Maximum plant height was observed with foliar
application of isolate PMK3 along with RDF i.e. treatment T15 (36.0 cm). Highest potato yield was
observed in foliar application of isolate PMK3 along with RDF i.e. treatment T15 which is 0.194 kg
respectively. Among the seven bacterial isolates (POK3, PMK3, COJ4, MUK1, WHK2, WHN1 and
WHN2) tested for plant growth promotion effect in potato crop, maximum plant growth promotion
effect was observed with bacterial isolate PMK3 and COJ4. So, bacterial isolate PMK3 and COJ4 may
be explored further for the field experiment.
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