Studies of the tetraploid potatoes. III. Progress in the experimental re-creation of the Tuberosum Group

Progress in a long-term experiment designed to re-create the Tuberosum Group of potatoes by selection from the Andigena Group is described. Both mass selection and pedigree methods are being used and current populations (5 years, 2 generations removed from South American sources) are estimated to be about half way from one Group to the other. Semi-natural selection for tolerance of long days results in earlier and heavier cropping and in certain correlated changes constituting the day-length syndrome; there has also been considerable response to natural selection for blight resistance, this selection having been advanced by growing sub-populations annually under heavy natural attack in Cornwall. It is concluded that the Tuberosum Group evolved under (semi-) natural selection for long-day tolerance and blight-resistance, supplemented by artificial (i.e. conscious, human) selection for tuber shape, size and colour and leaf size.