Potatoes (
Solanum tuberosum), in a further contrast, naturally reproduce by both sexual and asexual means. The natural pollination of potato flowers by insects capable of buzz pollination results in true (botanical) potato seeds (TPS) in berries. The genetically unique seedlings that arise from these seeds produce tubers which can sprout and grow into new potato plants, giving rise to a complicated mixed sexual/clonal system of reproduction. In the late nineteenth century, potato breeders started to switch from using natural open-pollinations to planned artificial hybridizations, to generate genetically unique seedlings and their clonal descendants from which to select new cultivars for tuber propagation. Hence, after the initial hybridizations, no more sexual reproduction was required to produce a new cultivar and therefore, in a sense, no knowledge of genetics was required. As a consequence, any impact of genetics needed to be through the production of parental material of known genetic constitution and predictable offspring. This included making use of the many wild tuber-bearing relatives of the potato in Central and South America, as well as the abundance of landraces in South America. The numerous potato-collecting expeditions to Central and South America, pioneered by the Russians in the 1920s, led to the establishment of a number of potato germplasm collections (gene banks) worldwide, including those established in Europe and North America in the 1940s and 1950s, and the world collection at the International Potato Centre (CIP) in Peru in 1971. The book by Hawkes,
The Potato: Evolution, Biodiversity & Genetic Resources, provides a useful summary of the germplasm that had become available to breeders by 1990, and the relevant knowledge that had accumulated to aid its utilization (Hawkes
1990).