Yacón

Appearance

Yacón is a perennial herb which grows up to 2.5 meters in height. The stem is cylindrical to angular and hollow when the plant is mature. Leaves are opposites and pointed. Their upper surface is hairy. Belowground tubers consist of branched roots and up to twenty tuberous storage roots.

The branched roots produce continuously aerial shoots, while the storage roots are the principal economic product of the plant. The storage roots are up to 25 cm long, 10 cm wide, gain a weight of 0.2 kg – 2.0 kg and have varying bark colours. The colour depends on the variety and ranges from white to pink to brown.

Frost causes the above ground parts to die back, but the plant sprouts again from the rhizome under favourable temperature and moisture conditions. The optimal growing temperature range is 18- 25 °C.Yacón plants produce small, inconspicuous flowers at the end of the growing season.

The timing of flowering strongly depends on the environmental conditions. If environmental conditions are favourable, flowering begins 6–7 months after planting and peaks about two months later. The yellow to orange coloured flower head is a pseudanthium . Each flower head is hermaphrodite which means that it units female and male florets in one pseudanthium. The yellow or orange ray florets are female and up to 12 mm long, while the yellow-brown disc florets are male and about 7 mm long. Seeds are stored inside achenes, which measure on average 2.2 mm - 3.7 mm and are dark brown coloured.

In general, seed production is rather low and some ecotypes do not produce any seeds at all, eventually due to pollen sterility. Plants produced by seeds grow slower than vegetatively reproduced plants.