Co-inoculation with Mesorhizobium ciceri and PGPR can improve chickpea (Cicer arietinum L.) growth in rain-fed and irrigated conditions

Abstract

An experiment was conducted to evaluate the effect of co-inoculation with <em>Rhizobium</em> and plant growth promoting rhizobacteria (PGPR) on chickpea growth under rain-fed and irrigated conditions. Treatments included inoculation with PGPR, co-inoculation with two strain of <em>Mesorhizobium ciceri</em> (SWRI3 and SWRI17), co-inoculation with SWRI3+SWRI17, co-inoculation with PGPR+SWRI3+SWRI17 and application of 25 kg nitrogen ha^-1 and no fertilizing as a control. Growth components analysis was estimated from growth curves fitted to the relationships between the measured variables and the temperature index measured based on growing degree days. Drought stress due to rainfed condition, caused significant reduction in crop growth parameters; however, bio-fertilizer improved growth significantly. The maximum LAI in the rainfed condition was 0.29 while co-inoculation with PGPR+SWRI3+SWRI17increased it to 0.54. Although, bio-fertilizers increased the time chickpea plants needed to reach their maximum LAI. In the irrigated condition, the highest CGR, TDM and seed yieldirrigated conditionwere 0.42 g m^-2 d^-1, 32.34g and 2335 kg ha^-1respectively and decreased to 0.23 g m^-2 d^-1, 18.34g and 1438 kg ha^-1 respectively in rain-fed condition that were also obtained from co-inoculation with all bio-fertilizers (PGPR+SWRI3+SWRI17) in both conditions. Overall, results suggest that using bio-fertilizer helps to alleviat drought stress in rainfed condition and could be recommended in semi-arid environment to maximize chickpea yield.