Abstract

B. Saritha Kumari, M. Raghu Ram* and K. V. Mallaiah

Rhizobium strains were isolated from root nodules of five species of Indigofera viz., Indigofera trita, Indigofera linnaei, Indigofera astragalina, Indigofera parviflora and Indigofera viscosa on Yeast Extract Mannitol Agar (YEMA) medium. The strains were examined for production of acid, exopolysaccharide (EPS) and indole acetic acid (IAA) by utilizing 10 different carbon sources. The Rhizobium strains isolated from I. trita, I. parviflora and I. viscosa showed maximum growth on glucose, while those from I. linnaei and I. astragalina showed maximum growth on fructose and maltose, respectively. All the five strains produced acid, EPS and IAA in Yeast extract mannitol broth. Among the strains studied, maximum EPS production was observed with the strain isolated from I. parviflora and maximum IAA production was observed with the strain isolated from I. viscosa.