CHOICE OF TRAP PLANT AND SUBSTRATE FOR MYCORRHIZAL INOCULUM PRODUCTION

Arbuscular mycorrhizal trap plants can be cultivated or wild species. In addition to withstanding anthropogenic pressure, these are excellent hosts for massive multiplication of arbuscular mycorrhizae. The objective of this work is to select the most suitable trap plant and substrate for the massive propagation of arbuscular mycorrhizal fungi. Four species were evaluated (Cajanus cajan, Cynodon dactylon, Tagetes patula, and Plectranthus tomentosa), two types of substrates (Substrate 1: sand, rice husk and vermiculite; Substrate 2: sand, rice husk and peat) and two phosphate sources (tricalcium phosphate and rock phosphate). At 120 days after inoculation, the percentage of mycorrhization and sporulation was evaluated. As a result, it was identified that the species Plectranthus tomentosa in substrate 2 was the most suitable, since it obtained a total mycorrhization of 79.7 % at a concentration of 1000 ppm of tricalcium phosphate, while in substrate 1 it had 67.5 % at the same concentration of tricalcium phosphate. This species also presented a higher number of spores (638 spore / 100 g soil) in substrate 1 at a concentration of 1000 ppm of tricalcium phosphate. In conclusion, the trap plant and substrate composition had a direct influence on the production of mycorrhizal inoculum.