Tarwi cross-pollinates so readily (the percentage of outcrossing may exceed 10 percent) that to preserve specific cultigens, such as low-alkaloid types, may require a special system of seed production and distribution. This factor particularly limits the increase of “sweet” tarwi in the Andes because of the recessive inheritance of the genes for low-alkaloid types and because bitter types are always nearby. Elsewhere (for example, in parts of North America), wild lupines14 may be a source of pollen pollution.
Current types are particularly sensitive to alternaria, a fungal disease that destroyed a large area of the crop in Peru in one recent year.
Eliminating problems caused by the bitter alkaloids would help tarwi advance as a world crop.15 Research is needed into improving the technology of debittering the seeds on a large scale. Also, the nonbitter varieties should be advanced to commercialization.
From the research already completed, it seems that strains with almost no alkaloids are available in nature or can be created artificially. The challenge now is to make them stable, so that the low alkaloid content is inherited uniformly by succeeding generations.16 Also, the initial low-alkaloid strains have been proven highly susceptible to insect attack. Breeding programs should seek plants that have alkaloids in the leaves but not in the seeds.17
Research to boost yield is also needed. Today, many flowers fail to set seed. Studies of pollination and fertility could point the way to helping the plant to approach its potential. (The failure to set seed is a characteristic of all lupins, and research on other species may also benefit tarwi.)
In any breeding program, high priority should be given to selecting early-maturing varieties for areas where growing seasons are short (for example, temperate latitudes and semiarid areas with short rainy seasons). Early-maturing types may also suffer less damage from pests