Environmental Requirements.

The plant is native to tropical latitudes (from 1°N to 22°S) but occurs mainly in cool valleys and basins at high altitudes. Thus it is a crop for cool climates (tropical highlands and temperate regions), not for the humid or arid tropics.

Daylength. Apparently neutral. Tarwi will flower and set seed both in the short (12-hour) tropical days and in the longer summer days in temperate zones.

Rainfall. The limits are unknown, but tarwi withstands exceptional levels of drought.

Altitude. From Colombia to Bolivia this species grows in the Andes at altitudes from 800 m to well over 3,000 m. In Australia, Europe, and California, it has been grown at or near sea level.

Low Temperature. Tarwi is semihardy. Mature plants are frost resistant; young plants are frost sensitive.

High Temperature. Unknown.

Soil Type. The plant is tolerant of sandy and acid soils, but in acid soils the production of rhizobium is very poor.

Related Species. The genus Lupinus is very diverse, with more than 100 different species in the New World and a smaller number in the Mediterranean region. Other than tarwi, all agriculturally important lupins derive from Mediterranean species. These, too, have important global promise.

The seed of Mediterranean lupins were rendered free of toxic alkaloids in the late 1920s and 1930s by the German researcher R. von Sengbusch, who isolated low-alkaloid (“sweet”) strains. These are now used as feed and fodder in Europe (especially the Soviet Union and Poland), the United States, Australia, and South Africa.

Of particular note is the narrowleaf lupin (Lupinus angustifolius). Nonbitter types with soft seed coats were discovered in Germany in the 1920s. Through 20 years of dedicated selection, the Australian scientist John S. Gladstones developed an early-maturing, sweet-seeded, nonshattering type. It is now widely planted in Western Australia as livestock feed, and its grain is exported to Europe.