Effect of microbial inoculants on the growth and yield of micropropagated banana (Musa indica) cv. Grand Naine

Abstract

SummaryMicropropagated plants generally exist in a sterile medium or environment and can thus benefit from inoculation with beneficial microbes to enhance their rate of survival following transfer from the laboratory to field conditions. The present investigation studied the beneficial effects of microbial inoculants (i.e., Azotobacter chroococcum and/or Piriformospora indica) on the growth and nutrition of micropropagated banana plantlets under glasshouse, as well as under field conditions (with 75% and 100% of the recommended doses of N and P). Dual inoculation resulted in the maximum rate of survival (84.6%) of micropropagated banana plantlets 2 months after transfer to a glasshouse. The maximum rates of colonisation by P. indica (76.5%) or A. chroococcum (at 147 × 104 cfu g–1) were observed 2 months after inoculation. The maximum mean root length (15.5 cm), shoot length (33.3 cm), root dry weight (DW; 2.0 g), and shoot DW (3.6 g) were observed in double-inoculated, micropropagated plantlets 2 months after transfer to the glasshouse. Plantlets were then transferred to the field. Suckers from the year-1 experiment were also transferred to another field and re-inoculated with either one or both microbial cultures for the year-2 experiment. In both years, the maximum mean numbers of leaves, stem diameters, plant heights, numbers of suckers, leaf areas, phosphorus contents, nitrogen contents, total chlorophyll contents, numbers of fingers, and fruit yields were observed in plants which had been co-inoculated with P. indica plus A. chroococcum, compared to non-inoculated control plants. Microbial inoculation (single or dual) improved plantlet survival rates, as well as the growth and yields of micropropagated banana plants compared to non-inoculated control banana plants.