Growth Promoting Activities of Different Rhizobium Spp., in Wheat

In the present study, large number of rhizobial strains were isolated from chickpea, lentil and mung been nodules and twenty fast growing colonies of each host legume, were selected. A series of jar experiments were executed and three most efficient isolates of each rhizobium species were screened on the basis of their growth promoting activities under axenic conditions. Results revealed that, in general, most of the isolates showed growth promoting effect but deleterious effect by some of the isolates was also observed on different parameters. The nine screened isolates were further evaluated for their growth promoting behavior in pots. The results indicated positive and increasing impact on growth and yield attributes by all the inoculants. However, in some parameters the increases were statistically same as with un-inoculated control. The isolates improved plant height (up to 18.66%), tillers per plant (up to 68.76%), straw yield (up to 35.14%), grain yield (up to 30.29%), 1000-grain weight (up to 28.40%), root length (up to 51.72%), % N in grains and straw (up to 15.07 and 33.16%), % P in grains and straw (up to 23.39 and 66.66%) and % K in grains and straw (up to 51.72 and 21.80%) compared with un-inoculated control. Finally, it is suggested that the procedure adopted for the selection of fast growing isolates and test of their growth promoting potential with wheat seedlings under axenic conditions could be an effective approach for screening the efficient and effective isolates. Also, the selected rhizobial strains could be used as PGPR for non-legumes.