Sindhu, S.S.Phour, Manisha2016-10-152016-10-152016http://krishikosh.egranth.ac.in/handle/1/80598In the present study, one hundred sixty two bacterial isolates were obtained from mustard rhizosphere soil. These bacterial isolates along with two reference strains were screened for production of amino-levulinic acid (ALA). Significant ALA production (> 15 µg/ml) was observed in bacterial isolates HMM21, HMM22, HMM80, HMM86, HMM92, HMM97, HMM115, JMM11, JMM15 and JMM35. Other eighty four isolates produced ALA ranging from 10.1 to 15.0 µg/ml. Ninety four bacterial isolates were selected on the basis of variation in ALA production ability and tested for salt tolerance at 1, 2, 4, 6 and 8% NaCl concentration. At 1% NaCl conc., ninety three bacterial isolates showed larger colony size ranging from 10.1-20 mm. At 4% NaCl concentration, only fifty six rhizobacterial isolates showed large colony size whereas only seventeen bacterial isolates showed large colony size at 6% NaCl concentration. Eleven bacterial isolates HMM6, HMM13, HMM34, HMM39, HMM44, HMM50, HMM65, HMM88, HMM92, JMM15 and JMM42 showed larger colony size (ranging from 10.1-20 mm) even at 8% NaCl concentration. Forty five rhizobacterial isolates were selected to study their inoculation effect on mustard seedlings on 0.8% water agar plates having different salt concentrations i.e., 0, 4, 6 and 8 dS/m. Eight rhizobacterial isolates HMM39, HMM44, HMM55, HMM57, HMM65, HMM73, HMM92 and JMM15 showed significant growth stimulation effect on seedling growth of mustard in comparison to uninoculated control at both 5 and 10 days of growth at different salt concentrations. These bacterial isolates also exhibited stimulation of root and shoot at 16 and 20 dS/m salt concentration except isolate HMM92, at both 5 and 10 days. Eleven isolates i.e., HMM21, HMM57, HMM76, HMM83, HMM92, HMM109, HMM116, JMM4, JMM24, JMM35 and CPS67 showed maximum retardation effect on seedling growth of Lathyrus aphaca. Based on their effect on growth of mustard and weed seedlings, eighteen rhizobacterial isolates were studied for other plant growth promoting activities. ACC utilization was observed only in eight bacterial isolates i.e., HMM8, HMM39, HMM57, HMM73, HMM92, JMM15, JMM19 and JMM24. HCN production was observed in two bacterial isolates JMM19 and JMM24. The IAA production was observed in all the isolates and it varied from 0.27 to 12.24 µg/ml. Thirteen bacterial isolates were found to possess phosphorus solubilizing activity. Three bacterial isolates i.e., HMM22, JMM15 and JMM19 were found to possess potassium-solubilizing index (K -SI) more than 5.0. Four bacterial isolates i.e., HMM92, JMM11, JMM19 and JMM24 were found to inhibit growth of two fungi Alternaria brassicae and Fusarium oxysporum. Eleven rhizobacterial isolates/strains were tested for their effect on growth of mustard and weed under pot house conditions. Rhizobacterial isolates/strain i.e., HMM76, HMM92, JMM24, JMM35 and SYB101 were found to stimulate growth of mustard along with inhibition of the growth of Lathyrus aphaca. At 75 days after sowing, inoculation of two bacterial isolates HMM92 and JMM24 showed 54 to 191% increase in RDW and SDW of mustard whereas they caused 36 to 92% decrease in RDW and SDW of Lathyrus aphaca. Rhizobacterial isolates i.e., HMM39, HMM57 and JMM15 stimulated growth of mustard 0, 8 and 12 dS/m salinity under pot house conditions. At 80 days after sowing, inoculation of three bacterial isolates HMM39, HMM57 and JMM15 caused 139 to 291% increase in RDW and SDW of mustard even at 12 dS/m. Based on the comparative analysis of various morphological and biochemical characteristics, the bacteria were found to belong to the genera of Aeromonas, Bacillus, Bacteroides, Brochothrix, Chrysemonas, Clostridium, Fusobacterium, Flavimonas, Hafnia, Mitsuokella, Meniscus, Photobacterium, Proteus, Pseudomonas and Serratia. Bacterial isolates JMM15, JMM24, HMM57 and HMM92 were identified as Pseudomonas azotoformans, Bacillus flexus, P. argentinensis and P. entomophila, respectively by the 16S rRNA sequence analysis. These bacterial isolate could be further exploited for growth improvement of mustard under field conditions.enPigments, Carotenes, Maize, Genotypes, Alleles, Genetics, Inbred lines, Selection, Locus, GenesThesis