Response of Azotobacter chroococcum in Pearlmillet under Dryland Farm Conditions

The present investigation was undertaken to study the effect of seed inoculation with biofertilizers. Response of eight strains of Azotobacter chroococcum, one strain of Acetobacter diazotrophicus and one strain of Azospirillum lipoferum was studied on pearlmillet for four years under dryland conditions. Results indicated that seed inoculation with various strains did not improve the grain yield of pearlmillet significantly. However, numerical increase of 0.6 to 2.2 q/ha was observed over uninoculated control. Among various strains tested, A. chroococcum Mac 68 performed better during all the four years of experimentation as compared with other strains. Average increase in grain yield during four years with inoculation of strain Mac 68 was found to 17.9% over control. The reasons for better performance by strain Mac 68 can possibly be due to high nitrogenase activity, high level of siderophores and also due to production of growth promoting substances.