Growth response of litchi to arbuscular mycorrhizal co-inoculation with Trichoderma viride, Azotobacter chroococcum and Bacillus megatarium

Abstract

To examine the microbial cooperation in the rhizosphere as reflected in terms of growth response of young trees (< 5 years) of litchi (Litchi chinensis), field experiments were conducted during 2012–2015 at ICAR-National Research Centre on Litchi, Muzaffarpur. The microbial inoculants consisting of arbuscular mycorrhizal fungi (AMF), Trichoderma viride (TR), Azotobacter chroococcum (AZ) and Bacillus megatarium (BM) along with their combinations were compared with application of recommended dose of fertilizers (RDF). The data revealed that AMF in combination with other microbial inoculants resulted in significantly higher increase in growth parameters viz., tree height, tree girth, tree spread, leaf area and leaf chlorophyll content. Growth response produced by combination of AMF + AZ + TR were the best or statistically at par (p = 0.05) with AZ + TR for most of the parameters. Similarly, significant higher root biomass, volume and density were observed with application of microbial inoculants. While AMF positively influenced the increase in population of T. viride and A. chroococcum, it negatively influenced the increase of population of B. megatarium which corroborated with the observed growth response of litchi trees. Thus, the studies not only confirmed the positive response of AMF and A. chroococcum reported in different crop species but also demonstrated a synergistic response of AMF with A. chroococcum and T. viride in litchi under field conditions.