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Subject: Microbiology × Author: Agrawal, Komal × End date: 2009 × Start date: 2009 ×
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    ThesisItemOpen Access
    Nodulation efficacy and characterization of rhizobial isolates from Macrotyloma uniflorum (Lam.) Verdc. and Lens culinaris Medik.
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2009-07) Agrawal, Komal; Sahgal, Manvika
    Biological nitrogen fixation (BNF) is an important attribute of symbiotic association of legume host with rhizobia. To achieve maximum BNF out of any legume rhizobia association it is necessary to assess nodulation and growth promotory potential of rhizobia. Further characterization of rhizoba is must before they are available for field application. Lens culinaris and Macrotyloma uniflorum are widely cultivated in Uttarakhand as pulse and forage crops. Thirteen rhizobial isolates (five from L.culinaris & eight from M. uniflorum) were assessed for nodulation, nitrogen fixation ability and growth efficacy on homologous host and heterologous host (Glycine max). These isolates were further characterized on the basis of cultural, biochemical and DNA fingerprinting techniques. Plate assays were performed for phosphorous solubilization and siderophore production. All five isolates from nodulated L.culinaris variety VL-507 but not G.max variety VL-63. Based on nodulation potential M.uniflorum isolates were placed in two groups, one (GR5, GR6, GR7, GR8) which nodulated M.uniflorum variety VLG-8 and second (GR1, GR2, GR3, GR4) which nodulated G.max variety VL-63. All L. culinaris isolates were fast growing with generation time in the range 1.95-2.25h and produced acid on bromothymol blue indicator plates. M.uniflorum isolates were placed in two groups based on generation time, fast growing (generation time 1.97-2.01h) and slow growing (generation time 6.80-7.046h).UPGMA dendrogram based on ARDRA of 16S with Alu I, Msp I & TaqI revealed that five L.culinaris isolates were genetically diverse and represented by three rDNA types. None of the rDNA type was related to Rhizobium leguminosarum bv. trifolii strain RCl2 39. M.uniflorum isolates were placed in two clusters none of the cluster were related to Bradyrhizobium elkanii strain USDA 76 & Bradyrhizobium japonicum strain USDA 06. Majority of the isolates were positive for solubilization of phosphorous and few isolates (GR1, GR3, GR5 and GR6) were positive for siderophore production.