Roots of Pfaffia sp. are used in the Brazilian popular medicine, especially for their tonic, aphrodisiac, and anti-diabetic properties. Sides and islands of the Paraná River are the natural habitat of P. glomerata (Spreng.) Pedersen, a species threatened due to intensive harvests. Therefore, its preservation demands the development of sustainable exploitation systems. In this framework, the seasonal variation of root biomass production and β-ecdisone contents were evaluated, using different Pfaffia glomerata accessions. Accessions were collected along the rivers Paraná (A1 and A3), Ivaí (A2), and Paranapanema (A4). Plantlets obtained out of these accessions were transplanted to its natural habitat, in a complete random blocks experimental design, with split-plots (accessions in the plots; harvests in the split-plots), and four six-plant replications. Four root harvests took place: at the eighth (May), tenth (July), twelfth (October), and fourteenth (December) month after planting. The highest root yield, assessed as dry mass, was found in the third harvest, 38.41 g plant-1. Accession A4 significantly outyielded the others, both in root fresh (94.67 g plant-1) and dry mass (26.39 g plant-1) yield. The ratio root fresh:dry mass, with an average of 26.91% (3.7:1), suffered little influence of accession origin. However, it was significantly altered along harvests (from 4.1:1, in the first harvest, to 3.3:1, in the third harvest, where it reached its peak). β-ecdisone content in roots was similar in the first three harvests, ranging from 0.26 to 0.38%, but with a sharp drop in the last harvest (0.16%). Accessions A2 and A3 had the highest β-ecdisone contents in roots, respectively 0.36 and 0.30%. Taking into account the results obtained in this work, we suggest the third harvest, twelve months after planting, as the most adequate for harvesting pfaffia roots.
Pfaffia glomerata (Spreng.); Pedersen; yield; suma; ginseng; active principle; medicinal plant
