Experiment 4: chickpea symbiotic rhizobia identification
To identify any naturalised Mesorhizobium able to nodulate
chickpea from the soil, the same three chickpea genotypes were grown in
the pots (20 cm diameter × 20 cm tall) filled with the same 5 soils used
in Experiment 1 with 4 replicates. The growing environment and
management were same to Experiment 1. Nodules were harvested at 6 weeks
after sowing, and washed by sonicator, as described above. DNA was
extracted from the clean nodules, amplified and sequenced using the same
process as the 16S rRNA gene amplicon sequencing.