Biochemical and folk assessment of variability of andean cultivated potatoes

Isozyme markers were used to survey the genetic variability of non-bitter potatoes in 10 subsistence fields of Andean farmers at 3600-3850 m above sea level. Sixty-seven percent of the varieties were tetraploids corresponding to the species Solanum tuberosum ssp. andigena, 14% were triploids, probably corresponding to the species S. x chaucha, and 13% were diploids corresponding to the species S. stenotomum, S. phureja, and S. goniocalyx. The isozyme information served to determine the consistency of the folk naming system. We found a high degree of correspondence between farmer identification and electrophoretic phenotypes. The consistency of the folk system in electrophoretic terms depended on the farmer who was interviewed. The most common incongruity consisted of calling different electrophoretic phenotypes by the same variety name, leading to a slight underestimation of genetic variability present in the fields. The amount of variability observed in the sample of the Andean potato population was superior to that present in North American and European varieties. This was measured in terms of number ofalleles, number of electrophoretic phenotypes and percent of heterozygosity. This finding supports the impression that a substantial amount of yet unexploited variability remains in Andean potato populations.