Page 160wall (pericarp) encloses each “seed,” and contains 0–6 percent bitter saponins. The seed is usually somewhat flat, and is normally pale yellow, but may vary from almost white through pink, orange, or red to brown and black. The embryo can be up to 60 percent of the seed weight. It forms a ring around the endosperm that loosens when the seed is cooked.
Horticultural Varieties. The cultivated plant shows great variability, and there is an enormous range of diversity. It has thus far defied classification into botanical varieties and, as with corn, the various forms are termed “races” or strains. A classification based on ecotype recognizes five basic categories:20
Valley type. Grown in Andean valleys from 2,000–3,600 m, these are tall, branched, and have long growth periods.
Altiplano type. Found around Lake Titicaca, these are frost hardy, short, unbranched, and have short growth periods and compact seedheads.
Salar type. Native to the salt flats in the Bolivian altiplano, these are hardy, adapted to salty, alkaline soil, and have bitter, high-protein seeds.
Sea level type. Found in southern Chile (mid-height), these are mostly unbranched, long-day plants with yellow, bitter seeds.
Subtropical type. Located in inter-Andean valleys of Bolivia, these are intense green plants that turn orange at maturity and have small, white or yellow-orange seeds.
The research of the past decades has produced several cultivars, selected and bred for their tolerance to heat and cold, resistance to disease, and for other desirable characteristics. Perhaps the oldest and most widespread of the new varieties are Kancolla and Blanca de Junín (selected in 1950 in Peru) and Sajama (selected in Bolivia in the 1960s). Sajama is particularly interesting as it has large, white seeds, no saponins, and under good conditions will yield 3,000 kg per hectare. In the early 1980s, a new sweet variety was obtained at Cuzco (from Colombian material) and named “Nariño.”
Peru and Bolivia have the most extensive collections of these different races, each having over 2,000 ecotype samples. Other collections exist in Chile, Argentina, Ecuador, Colombia, the United States, England, and the Soviet Union.