Beneficial microorganisms enhance the growth of basil (Ocimum basilicum L.) under greenhouse conditions

Abstract

The integration of healthy management alternatives continues to be a challenge in the organic production of aromatic and medicinal plants, including of basil (Ocimum basilicum L.). The objective of this work was to evaluate the effects of three beneficial microorganisms (1) Trichoderma harzianum (TH), (2) Bacillus subtilis (BS), (3) Glomus cubense (GC) and their combinations on the growth of basil. A completely randomised design was used with a control and seven treatments with six repetitions. The control (1) was with no microorganism inoculation and the seven treatments were inoculations with the single or the combined microorganisms as follows: (2) TH, (3) BS, (4) GC, (5) TH+BS, (6) TH+GC, (7) BS+GC and (8) TH+BS+GC. Three harvests of fresh biomass were made and a number of growth variables were recorded: fresh and dry biomass, leaf area, number of commercial stems, stem length and thickness, Leaf length and width, relative chlorophyll concentration (SPAD readings) and the levels of N, P, K, Ca and Mg. Overall growth increased by 58% with TH+GC compared with the control and by 55% compared with the single inoculations (TH, BS and GC) and with the triple inoculation (TH+BS+GC). A growth increase of 51% was obtained with BS+GC compared with the control and of 38% compared with the other treatments. These results indicate co-inoculation of TH+GC or of BS+GC are useful alternative managements to increase greenhouse production of basil.