ABSTRACT
Radiocarbon dating has shown that potato cultivation started at least 8,000 years ago in southeast Peru and northwest Bolivia (Engel, 1970). There are no authentic records to show when potatoes were first the subject of conscious selection by man, but it must have started as soon as potato cultivation was undertaken. It is probable that growers started to exercise choice among the different “types” available to them, and much of the selection required to produce most of the present-day varieties was carried out during the early stages of potato domestication. Potato breeding in the modern sense began in 1807 in England when Knight (1807) made deliberate hybridization between different varieties by artificial pollination. As with other crop species, potato breeding gained impetus with the increase in understanding of the science of heredity and the rediscovery of Mendel’s law of inheritance in 1900, initially published in 1865. However, cultivated potato Solanum tuberosum proved to be a difficult species for genetical research because of its complex inheritance patterns and it was not until the end of the 1930s that geneticists recognized that it was a tetraploid (2n = 4x = 48) that displays tetrasomic inheritance. Furthermore, most traits of economic importance displayed continuous variation for which Mendelian analysis was not 78possible because distinct classes could not be discerned. As a consequence, potato breeding remained empirical and genetically unsophisticated till now.
