EFFECT OF RHIZOSPHERIC BACTERIA ON PLANT GROWTH OF WHEAT INFECTED WITH HETERODERA AVENAE

Abstract

Some rhizospheric bacteria were tested in potted plants to assess their possible mitigatory effect against the cereal cyst nematode, Heterodera avenae infecting wheat. Azotobacter chroococcum, Azospirillum lipoferum and Pseudomonas sp. reduced nematode infection to various levels while Rhizobium ciceri had no apparent effect. Six out of eight strains of A. chroococcum showing different properties like nitrogen fixation, ammonia excretion, indole acetic acid (IAA) production and siderophore production reduced cyst formation from 6 to 60 per cent. Strain 1 (1) and Mac 27 having high siderophore production did no control nematode infection but high temperature resistant mutant HT54, possessing the highest ammonia excretion ability and negligible IAA production, reduced nematode infection by 48 per cent. Results indicated that ammonia but not siderophores or IAA had a role in the control of H. avenae infection in wheat. All strains of A. chroococcum in general and HT 54 in particular promoted growth of nematode infected wheat plants.