In areas prone to frost, it requires some protection in winter. The cultivar T. tuberosum var. lineamaculatum 'Ken Aslet' has gained the Royal Horticultural Society's Award of Garden Merit. Medicinal properties Mashua has putative anaphrodisiac effects. It has been recorded by the Spanish chronicler Cobo that mashua was fed to their armies by the Inca Emperors, "that they should forget their wives". Studies of male rats fed on mashua tubers have shown a 45% drop in testosterone levels due to the presence of isothiocyanates. Mashua contains Docosatetraenoylethanolamide, a cannabinoid structurally similar to Anandamide that also acts on the cannabinoid (CB1) receptor among other structurally related compounds such as N–oleoyldopamine. See also Oca New World crops Ulluco Yacon References tuberosum Root vegetables Perennial vegetables Crops originating from the Americas Crops originating from Peru Anaphrodisia Crops originating from Bolivia Crops originating from Colombia Crops originating from Ecuador Plants described in 1802