Biofertilizers in the growth of tarragon (Artemisia dracunculus L.) under greenhouse conditions

Tarragon (Artemisia drancunculus L.) is a perennial and aromatic plant with production potential in Me-xico. The objective was to evaluate the simple and combined effect of Trichoderma harzianum, Bacillus subtilis and Glomus cubense on the growth of tarragon under greenhouse conditions. A completely ran- domized design with six replications was used. The treatments were: 1) Control (without inoculations), 2) Trichoderma harzianum, 3) Bacillus subtilis, 4) Glomus cubense, 5) Trichoderma harzianum + Bacillus subtilis, 6) Trichoderma harzianum + Glomus cubense, 7) Bacillus subtilis + Glomus cubense, 8) Trichoderma harzianum + Bacillus subtilis + Glomus cubense. The cumulative effect on the growth of tarragon was measured through three cuts of commercial stems, in which it was evaluated: fresh and dry biomass, leaf area, number of commercial stems, length and thickness of the stems, length and width of the leaves, SPAD readings and the extraction of N, P, K, Ca and Mg. The tarragon plants co-inoculated with T. harzianum + G. cubense had an increase of 66 % in growth with respect to the control and of 53 % in comparison with simple inoculations and the treatment with the three microorganisms. In addition, a 57 % increase in plant growth was obtained with the combination of T. harzianum + B. subtilis compared to the control and a 33 % increase with the rest of the treatments. The biofertilizers T. harzianum + G. cubense and T. harzianum + B. subtilis, can be an alternative for the organic management of tarragon.