Enhancement of shelf life of liquid biofertilizer containing Rhizobium sp. infecting mungbean (Vigna radiata L.)

Abstract

To solve the shorter shelf life, high contamination, poor quality, low field performance and processing solid carrier in carrier based bioinoculant formulation had necessitated the shifting of carrier based inoclants to liquid inoculants technology. Three different polymeric additives; polyvinyl pyrrolidone, gum arabic and glycerol were evaluated for their ability to support growth and promote survival ofliquid inoculants (Rhizobium sp. strain MB1503) during the storage. All liquid rhizobial inoculants prepared in amended media showed higher viable count in comparison to inoculants prepared in YEMB (control) at 180 d of storage. Maximum survival was observed in inoculants prepared in YEMB amended with2% PVP, 2% GA and1% GA. Mungbean (Vigna radiata L.) seeds treated with 90 d old liquid rhizobial inoculant of strain MB1503 amended with 1% PVP or 2% glycerol enhanced plant growth as compared to uninoculated control. The present investigation revealed that treatments inoculated with 90 d old inoculant + amendments (added before or after the growth) were significantly better with respect to nodule weight, shoot weight and total plant nitrogen as compared to uninoculated control/treatment.