Coinoculation 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-inoculation 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 Endogone duseii (VAM) and PGPRs. The better performing PGPR were Azospirillum brasilense CD,Azotobacter chroococcum CBD-15, fluorescent pseudomonad strains PF-I 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.