Abstract
Plant growth regulators and Rhizobium are actively involved in the regulation of flowering, pod formation, nodulation, and ultimately the growth and yield of legumes. However, very limited information is available on the combined effect of gibberellic acid (GA(3)) and Rhizobium on growth attributes and yield of legume crops. This experiment was designed to fill this gap by studying the performance of chickpea under exogenous application of GA(3) (10(-4) and 10(-5) M) alone and in combination with Rhizobium. Exogenous application of GA(3) (10(-5) M) combined with rhizobium inoculation gave the highest values for number of nodules per plant (16) and their dry biomass (0.22 g). Moreover, GA(3) application and seed inoculation with Rhizobium, when applied singly, significantly enhanced chickpea growth. However, the most promising results were obtained by the inoculation of Rhizobium accompanied with GA(3) (10(-5) M). Plant height, grain and stover yield, and chlorophyll contents were enhanced up to 35%, 39%, 21%, and 51%, respectively. Likewise, the bioaccumulation of macronutrients (N, P and K) was maximum in plants receiving both Rhizobium inoculation and GA(3) application. It is concluded that the combined application of Rhizobium and GA(3) has synergistic effects on the growth, yield, and nutrient contents of chickpea.