Comparative potential of Rhizobium species for the growth promotion of sunflower (Helianthus annuus L.)

Abstract

Rhizobium besides its nodule formation characteristic with members of Fabaceaefamily has been recognized for its great root colonizing ability and growth hormoneproduction potential. In addition to nitrogen fixation in legume plants, rhizobiaconsidered as beneficial tools and act as plant growth promoting rhizobacteria (PGPR)with many non-legumes. Present study was elucidated to determine the comparativerole of Rhizbium sp for growth promotion of sunflower. Rhizobia were isolated fromfive different legumes (mungbean, barseem, lentil, chickpea, and vegetable pea) andchecked for their auxin production efficiency. Rhizobial isolates Cp-4 showed maximumauxin potential (5.37 µg mL-1IAA equivalents).Results showed that inoculation of allrhizobial isolates caused significant increase in growth and physiological parameters ofsunflower plants. While prominent results were found with inoculation of mungbeanrhizobial isolate Mb-2 which increases the chlorophyll a, N, P, fresh and dry matter ofsunflower significantly by 8.34, 4.9, 36, 31, and 34%, respectively in comparison to uninoculated control plants. Hence, present study concluded that Rhizobium sp can besuccessfully used as PGPR in non-legumes after thorough investigations.