Yacon (Polymnia sonchifolia Poep End.) is a species from the Asteraceae family which presents a complex subterraneous system. Its tuberous roots and rhizophores contain great amounts of free fructose and glucose, besides inulin type fructo-oligosaccharides as reserve carbohydrates. It has raised interest mainly for its medicinal properties, being used as an auxiliary in the treatment against diabetes and cholesterol. It was introduced in Brazil around 1989, but only in 1994 the first commercial cultivation started. It is presently cultivated in the Capão Bonito region, São Paulo State, from rhizophores weighing from 60 to 80 g. These are planted in beds 0.30 - 0.40 m high, 1.0 m wide, in a 1.0 x 0.90 m interspace. Soil pH is adjusted to 6.0 and the basic fertilization is made with NPK + Zn according to soil analysis and to some recommendation for sweet-potatoes. Later on, 40 kg.ha-1 of N are added, divided in two applications. Irrigation is made by sprinkle irrigation and harvesting happens between the 8th and 10th months after planting, yielding an average of 80 t.ha-1 of tuberous roots and 1 t.ha-1 of fresh leafs. Roots as well as leafs can be freshly consumed or dehydrated in a stove with forced ventilation at 50(0)C maximum temperature to avoid loss of reserve carbohydrates as well as the secondary metabolism substances.
Polymnia sonchifolia Poep. Endl; store carbohidrate; diabetes; production system; post-harvest
