temperatures. There are fumigants available to fight Verticillium, or, for organic farmers, annual rotations into soil that has not been infected for 2–3 years. Ulluco is also susceptible to Rhizoctonia solani, though not as susceptible as the potato. This pathogen can reduce the amount and quality of the yield. Slugs and snails are common pests, though generally only cause cosmetic damage to the ulluco. Breeding The ulluco has a limited ability to produce a seed. It was thought to be infertile until researchers in Finland produced a seed in the 1980s. This low fertility poses a challenge when trying to breed this crop. This infertility is thought to be due to the long history of cultivation by planting tubers. However, the ullucus has high genetic diversity, in terms of color, protein content, and tuber yield. It is thought this diversity arises from somatic mutations or from sexual regeneration. Ullucus is primarily bred from seed tubers, but it is also possible by seed and stem cuttings. In New Zealand there have been experiments to induce mutation by gamma radiation and produce more varieties. Research needs There may be potential for much higher yields of ulluco and a larger role in the world food system. Potential research into virus free varieties, the photoperiod, and seed producing varieties could expedite this. This could allow for manipulation of colors and other genetic factors. This could also lead to an increased adaptability for ullucus to be grown around the world. Cultivars The majority of accessions are diploids (2n=24). Triploids (2n=36) and tetraploids (2n=48) are rare. With 187 accessions evaluated with 18 morphological descriptors, 108 morphotypes or groups have been identified. Considering that the reproduction of the species is vegetative and that the production and use of the germination of botanical seeds is very rare, morphological diversity of the ulluco can be seen as high. The main characteristics that determine the choice of farmers for cultivars are sweetness, storage capacity before consumption, mucilage content and yield. Skin color is also a key parameter to consider while assessing the potential of the ulluco culture. Red tuber plants are the most frost-resistant and yellow tubers are the most popularly eaten in markets in Ecuador. The attractiveness of the color of cultivars varies among countries and regions. In the New-Zealand market, the preferred skin color was red over plain yellow and mixtures of yellow, green and red. Unusual and