STUDIES ON GENETIC DIVERSITY OF PHOSPHORUS SOLUBILIZING RHIZOBIA OF RAJMASH (PHASEOLUS VULGARIS L.)
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Date
2019-11
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UHF,NAUNI
Abstract
ABSTRACT
The present investigations were conducted to determine the genetic diversity of P-solubilizing
rhizobia of rajmash by amplified ribosomal DNA restriction analysis (ARDRA). A total of 50 isolates
associated with rajmash were authenticated as Rhizobium spp. on the basis of different authentication
tests,viz.congo red test, bromothymol blue test, growth in Hofer’s alkaline broth, ketolactose medium
and plant infection test. Out of 50 rhizobial isolates, all were P-solubilizers, sixteen were siderophore
producers, nine were HCN producers, eight isolates showed antagonism against Rhizoctonia solani
Kuhn and five against Colletotrichum lindemuthianum Sacc. and Mangus. The maximum
P-solubilization (295.74 µg/ml) was recorded for isolate KS and maximum IAA production (83.19
µg/ml) was noted for isolate Har4. Maximum siderophoreproduction with zone size of 19mm was
recorded with the isolate Shl7 on CAS medium. On the basis of banding pattern generated through
ARDRA analysis using restriction enzymes Alu I and Msp I, 19 isolates from agro-climatic zone-II
were grouped into seven major phylotypes at 49 per cent similarity level, 15 isolates from agroclimatic
zone-III were segregated into five major phylotypes with 49 per cent similarity and 16
isolates from agro-climatic zone-IV were grouped into seven major phylotypes at 57 per cent
similarity level. Seed bacterization with 10 selected rhizobia resulted in significant increase in shoot
height, root length, plant biomass and number of nodules over uninoculated control. Among 10
sequenced rhizobia, 4 isolates viz. Hab3, BhrB, Tis2 and San1 were identified as Rhizobium nepotum,
3 isolates viz. KAF, Har1 and Kal3 as Rhizobium indigoferae, isolate KS as Rhizobium etli, isolate
Har2 as Rhizobium acidisoli and isolate Shl3 as Rhizobium pusense. Seed bacterization with R. etli
strain KS+70% P showed considerable effect on increase in shoot height (86 cm), root length (28.30
cm), number of nodules (55.07 no./plant) and available NPK over uninoculated control at flowering
stage as well as harvest of the crop.
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