Gera, RajeshSwati2019-03-272019-03-272019http://krishikosh.egranth.ac.in/handle/1/5810099522Chickpea is one of the most important legume crop in India and the world‟s second most cultivated legume grown as a winter crop in Indian subcontinent. It is highly rich in good quality proteins and mainly used in vegetarian diet. A total of 52 rhizobial isolates were included in the present study, out of which 48 rhizobial isolates were retrieved from nodule samples collected from four different districts of Rajasthan and 4 chickpea rhizobial isolates were obtained from departmental culture collection. Screening of these rhizobial isolates for abiotic stress tolerance showed that almost all the rhizobial isolates tested were able to grow up to 30°C. However, 36 and 5 rhizobial isolates showed good growth at 35 and 40°C, respectively. Similarly all the rhizobial isolates showed growth at 100 mM NaCl concentration. However, increase in NaCl concentration from 300 mM to 500 mM significantly reduced the growth of most of the rhizobial isolates. In addition only 25 isolates showed growth upto 40% PEG concentration. On the basis of abiotic stress tolerance, 24 rhizobial isolates were selected, which further characterized for different PGP traits. Ten isolates showed phosphate solubilization on Pikovskaya,s agar medium plates. The P-solubilization index of these isolates varied from 2.15-3.33. Fifty percent of rhizobial isolates were also found to be bacteriocin producer. However, only 7 rhizobial isolates showed siderophore production. The ammonia excretion and IAA production was observed in all the rhizobial isolates which varied from 1.79 to 4.89 μg/ml and 2.32 to 57.06 μg/ml, respectively. ACC utilization was observed in 96% rhizobial isolates. Genomic DNA of all the stress tolerant rhizobial isolates showed the presence of nodC gene however, only 18 rhizobial isolates showed the presence of nifH gene using two different sets of gene primers i.e. 19F, 407R and nifH1, nifH2. Genomic DNA of all the selected chickpea rhizobial isolates were also amplified for 16S rRNA gene using 27F and 1378R primers. The 16S rRNA amplified product was subjected to RFLP analysis with MspI and HaeIII restriction enzymes. Dendrogram based on restriction analysis showed enormous diversity among themselves with both of the restriction enzymes. Three chickpea rhizobial isolates i.e., CPR40E, CPR59A and CPR24B were found as most efficient rhizobial isolates on the basis of nodulation efficiency and plant growth promotion parameters in pots under screen house conditions. These rhizobial isolates can be used as potential biofertilizer for rain-fed areas after testing their efficacy under field conditions.ennullThesis