Sustainable chickpea (Cicer arietinum L.) farming with plant growth-promoting rhizobacteria (PGPR): A novel approach

Sustainable agriculture is paramount to addressing global food security challenges, particularly in the context of climate change and soil degradation. Chickpea (Cicer arietinum L.) stands out as a vital legume crop due to its high nutritional value and ability to improve soil health through nitrogen fixation. It's primarily cultivated during the Rabi season throughout India. In Tamil Nadu, it's grown in the western districts, where favorable climatic conditions like high relative humidity and cool temperatures prevail. Despite these advantages, chickpea production has declined due to various pests and diseases. Consequently, the use of varieties highly susceptible to wilt (13 %-33.6 %) during the cropping period causes significant yield losses, ranging from 15 % to 40 %. Additionally, existing cultivars are highly susceptible to pathogens, their potential mutations and prevalence. With this background, our study focused on identifying, characterizing and evaluating the growth-promoting and disease-management potential of rhizobacterial strains. In this study, 19 rhizobacterial strains (CPs1-CPs9; CBs1-CBs10) were collected from the chickpea rhizosphere. These strains were further characterized as Pseudomonas and Bacillus spp. using cultural, morphological, biochemical and molecular methods (MK254689 to MH745128; MH746113 to MK290646). Among these strains, CPs3 (P. chlororaphis - MH628219) demonstrated maximum germination (100 %) and a yield of 1194.4 kg/ha. It also showed the lowest wilt incidence (14.3 % in the glasshouse and 21.67 % in the field), achieving a maximum disease reduction of 70.1 %. This was associated with the highest population density (8.2 × 105 cfu/g of soil) observed 35 days after sowing on cv. CO4 in the root zone (approximately 3 cm to 5 cm from the root).