Studies of the tetraploid potatoes

The Andigena Group of potatoes is an extremely variable complex of tetraploid Andean cultivars which ranges geographically from the Caribbean to Bolivia. They are self-compatible, outbred and variably fertile. Some hundreds of samples of the group in the Commonwealth Potato Collection were scored for various characters, some stocks being grown as seedling lines in the field, others as clones in the glasshouse. Results are presented as frequencies of characters analyzed by means of contingency X2 tests. Conclusions are: that all characters are found in all parts of the range and there is, at most, slight geographical heterogeneity, of which the only consistent trends are towards relatively high frequencies of larger leaves and stronger pigmentation towards the northern end of the range and the converse towards the south; associations between characters are mostly few, slight and inconstant; they lend no support to the idea that the group is taxonomically differentiated. The potatoes of Chile present a quite different picture: they differ from the Andigenas and resemble the Tuberosum Group in daylength adaptation and large leaves but are reminiscent of the Andigenas in the frequencies of other characters; collectively they thus differ from both the other major groups of tetraploid potatoes and it may be significant that they show signs of heterogeneity.