Isolation of Azospirillum and evaluation of the effect of four superior isolates on the germination of Canola seeds

Azospirillum is one of the plant growth-promoting bacteria which is in the rhizosphere and the intercellular of the cereals and other plant roots. One of the characteristics of this bacterium, considered in this study, was its effect on the germination ability of inoculated seeds. In this research, 58 Azospirillum isolates were isolated from 38 samples of soils and canola roots from the different regions of Golestan province, Iran and then they were compared to select superior growth promoting isolates. The effect of inoculation with 4 superior isolates along with control (noninoculated) was evaluated on some germination parameters of canola seeds (Hayola 401) in randomized complete block design (RCBD) with 8 replications. Results showed that germination percentage, average of germination time andgermination rate were significantly different (p<0.01) among various isolates. The inoculationof canola seeds germination percentage and germination rate decreased and germination time increased as compared to the control. AC34-III isolate produced the minimum amount of auxin, so the lowest germination percentage and germination rate were attributed to it compared with other isolates. Moreover the higher auxin-producing isolate)Ac43-III(showed the maximum germination percentage that was introduced as the best bacterial treatment.