Influence of herbicides on chickpea-Mesorhizobium symbiosis

An experiment was carried out under greenhouse conditions in order to evaluate the effects of soil applications of bentazone, isoproturon, fluchloralin and 2,4-D on plant vitality, chlorophyll content, N and protein content, nodulation and seed production in chickpea, inoculated with Mesorhizobium ciceri. Applying ten times the recommended rates of all herbicides adversely affected the plant vigor, total chlorophyll content and nitrogen (N) content in shoot and seed production. Fluchloralin and 2,4-D gave the highest adverse effects on seed production in chickpea while protein content in seeds increased significantly following herbicide applications but decreased with an increase in application rates. The ten times the recommended rates of bentazone and 2,4-D completely decreased nodulation. Nodule occupancy determined by immunoblot assay ranged between 72 and 89 percent, while each rate of the four herbicides except the normal dose of bentazone showed an adverse effect on rhizobial populations within single nodules of the chickpea plant.