[deck]Why wild potato species and heirloom cultivars play a crucial role in future food security.[/deck]
From time to time, new potato diseases may break out, or old diseases and pests may spread into areas where they were, thus far, unknown. Wild potato species and heirloom cultivars represent a great treasure in terms of genetic resistances against current and/or future diseases and pests, and therefore represent a very valuable resource for future generations of potato producers and consumers alike.
Many of the wild relatives of the potato are growing in areas that, from the standpoint of potato cultivation, could be considered rather unusual. Some of these species are now losing their natural habitat, as a result of such factors as deforestation, increased grazing pressure, irrigation of dry lands and changing farm practices, including the use of herbicides and destruction of field borders with increasing field sizes.
When the natural habitat for these wild species changes drastically, the plants are often no longer able to compete with the new surrounding vegetation and, as a result, may become extinct. Several effective solutions are now in place to prevent the loss of these valuable resources for the future.
One way to preserve the valuable genes that endangered wild species may contain is to preserve them off-site in gene banks. There are seven major potato gene banks around the world. Because they are seen as public trusts, they are managed and funded by national governments.
The principal North American potato gene bank is located in Sturgeon Bay, Wis. Its current holdings include nearly 5,000 samples of more than 140 species. In addition to contributing to this gene bank, Canadian scientists also have access to its vast resources for future research.
Most gene banks publish inventories of their holdings to provide scientists relatively easy access. An efficient way to maintain and distribute these genetic resources is via “true” or botanical seed. Recent developments in tissue culture enable gene banks to multiply and ship various potato genotypes in vitro, which literally means “in glass”.
Heirloom cultivars are also described as heritage, traditional, vintage, antique or classic cultivars. It has been suggested that for a cultivar to be considered heirloom, it should be at least 50 years old. Such cultivars may contain useful genes that are no longer present in modern cultivars used today.
There are many heirloom cultivars. Examples of North American heirloom cultivars include All Blue, Banana, Green Mountain, Irish Cobbler and Warba.
Since potato cultivars are maintained by vegetative propagation, they tend to accumulate viruses and other diseases that can be readily passed on to the next generation through the tubers. Diseases carried in potato tubers can be a problem when potato cultivars are exchanged on an informal basis, that is, without the benefit of a seed potato certification program.
To avoid this problem, Agriculture and Agri-Food Canada operates the Potato Gene Resources Repository at the Potato Research Centre located in Fredericton, N.B. The repository’s 2012 annual report shows an inventory of 166 accessions, of which 49 per cent are heirloom cultivars.
Nearly all of this material is maintained in disease-free condition in vitro, and is available in small quantities for breeding, research and evaluation purposes, as supplies allow. Descriptions of many heritage cultivars, including pictures, can be found in the Potato Gene Resources Newsletter as well as in catalogs of the Seed Savers Exchange in the United States and Seeds of Diversity Canada.
Native Andean Cultivars
The International Potato Center in Lima, Peru has extensive holdings of more than 4,000 native Andean cultivars — potatoes originally domesticated in the Andes Mountains — in its gene bank. Many of these cultivars are several centuries old and represent a great treasure of distinctive traits including unique colours and shapes, nutritional qualities, and genetic resistances against current and/or future diseases and pests.
Many of these native cultivars are also maintained in several easily accessible “potato parks” in the country, where local Peruvian farmers not only care for them but also maintain the social/cultural values of specific cultivars. The potato parks are open to the public; the best known one is located in Sacred Valley of the Incas in Cuzco, Peru.
Potato parks represent a novel approach towards creating a greater public awareness of the importance of conservation of valuable cultivars. This in turn is part of humankind’s insurance policy for future food security.