Potential of Competitive and Efficient Mesorhizobium Strains to Improve Chickpea Growth, Yield, and Soil Health

Legume-rhizobial symbiosis plays a crucial role in agricultural sustainability. Mesorhizobium, a major root symbiont, is known to influence nodulation, nitrogen fixation, and yield in chickpea. However, there is a significant lack of research on its competitiveness and nodule occupancy in saline environments. In the present study, experiments were conducted to assess the growth kinetics of 12 Mesorhizobium strains and to evaluate their plant growth-promoting activities towards enhancing competitiveness for nodulation. All strains showed different growth rates, ranging from 0.10 to 0.26 per hour, and generation times ranging from 2.64 to 6.66 h. Strains C101 and C95 showed maximum bacteriocin production potential as compared to the other Mesorhizobium strains. Strain C101 showed considerable P, K, Zn solubilization potential and nitrate reductase activity. Furthermore, a field investigation was conducted by seed priming to evaluate the persistence and effectiveness of these treatments under environmental conditions. In strain C101-inoculated plants, significant enhancement in shoot length, fresh weight, leaf IAA, total pigments, and nitrate reductase activity by 52, 80, 54, 37, 72