Co-inoculation effect of VAM and PGPR on growth and yield of onion

Abstract

The possibility of using biofertilizers in crop production concomitant with enriching soil has attained significance in recent years. Six of the plant growth promoting rhizobacteria (PGPR) and a Vesicular Arbuscular Mycorrhizae (VAM) species Endogone duseii were applied on onion cultivar Pusa Madhavi, singly and in combination with reduced inorganic fertilizer dose. Co-inocultion of VAM with non-symbiotic N2 fixing PGPR strains proved to be the best treatment to promote growth and yield of onion. Dual inoculation could meet almost 50 percent of the nitrogen and phosphorus demand of the crop. All the traits studied showed a significant increase with the application of half of the recommended dose of N and P along with VAM and PGPRs. The better performing PGPR were Azospirillum braslense CD, Azotobacter chroococcum CBD-15, Fluorescent pseudomonad strains PF1 and PF-IV. The soil available nutrients, especially N, after crop harvest were moderately improved. Biofertilizer application was also found to have influence on reducing the storage losses of cured onion.