Development and Screening of Plant Growth Promoting Efficacy of Rhizobium-PGPR Based Formulation in Vigna Unguiculata

Abstract: Cowpea is a food legume having significant importance worldwide as it is rich in proteins, vitamins and minerals. Rhizobium is a well-known nitrogen fixer which also produces some plant hormones. The present research work envisages the development of Rhizobium-PGPR consortia formulation involving enriched coir pith for growth enhancement in Vigna unguiculata. A total of four bacterial isolates were isolated from soil and root nodules and four isolates were confirmed through biochemical characterization as Rhizobium spp. Bioformulation involving Rhizobium and IAA producing Bacillus ascii using Coir pith as organic carrier was prepared. In a new attempt, the coir pith was enriched with nutritional solution and used as an organic carrier for development of said bioformulation. The pot culture study was undertaken with different treatments using the CRD design with three replicates to test plant growth efficacy of the bioformulation. Seed and soil treatment using enriched carrier material exhibited better shoot growth promotion (75.08±16.79) when compared with control (65.33 ±11.72) and commercially available biofertilizer (73.37±9.57) .This is a first attempt to develop a bioformulation using Rhizobium and IAA producing bacteria for growth enhancement in Cowpea. The results obtained clearly reveal a novel outcome wherein the enriched carrier material exhibited better growth enhancement than non enriched carrier materials. The bioformulation developed has been currently tested in field trials with farmers by means of a participatory approach.