Selection of Resistant Varieties of Potatoes (Solanum spp) for Seeds
Potato is the third most important food crop in the world after rice and wheat. It is a major carbohydrate present in the diet of hundreds of millions of people in developing countries and fundamental to the diets of populations in countries across South America, Africa, Central Asia and Asia (International Potato Centre 2010). The potato yields more nutritious food more quickly on less land and in harsher climates than any other major crop: up to 85 per cent of the plant is edible human food, while for cereals the figure is around 50 per cent (International Potato Centre, 2010).
The selection of crop varieties that are resistant to hostile climates allows agricultural activities to continue, even in extreme climate scenarios that are (i) unexpected due to extreme climate variability resulting from climate change; (ii) expected by early warning systems; or (iii) expected according to seasonality. In this sense, the same technology can be applied to different scenarios.
For the cultivation of native potatoes resistant to droughts, frost and heavy rainfall (excess of water but not flooding), tubers for botanical ‘seeds’ are selected based on the following criteria:
- Preferably of a medium size
- Sturdy and with a good appearance
- With a large number of eyes (meristem tissue).
Traditionally, the selected tubers are stored separately from the product for consumption, for use in the next farming season.
Selecting varieties highly resistant to both droughts and high humidity creates the right conditions to deal with two of the most regularly occurring climatic scenarios caused by climate change. This reduces the risk of losing entire plantations, thus guaranteeing the availability of a minimum quantity of potatoes, a strategic food for people in developing countries. This technology also provides the opportunity for potato farmers to produce a surplus for the local market and thus earn more income to cover basic needs.
A limitation of this technology that is worth bearing in mind is that native varieties do not yield as much as genetically improved varieties, the volume and weight of which are greater (tons per hectare). Native varieties can produce as much as 10 t/ha, specialists say the average is 7 t/ha (Medina, 2010; and Torres, 2010), whereas other varieties produce more than 10 t/ha. However, the genetically improved varieties are far less resilient to extreme changes in weather conditions.
CCTA (2006) Proyecto In Situ. Tecnologías Apropiadas no Tradicionales en la Conservación In Situ de Cultivos Nativos en el Perú, Institución promotora o conocedora: CENTRO IDEAS (Centro de Investigación, Documentación, Educación, Asesoría y Servicios); Grupo TALPUY; Instituto Nacional de Investigación y Extensión Agraria INEIA – EE Santa Ana
cited in: Clements, R., J. Haggar, A. Quezada, and J. Torres (2011). Technologies for Climate Change Adaptation – Agriculture Sector. X. Zhu (Ed.). UNEP Risø Centre, Roskilde, 2011, available at http://tech-action.org/
An awareness of the following is required to implement this technology:
- The genetic variability of native varieties
- Principles of experimentation in the field
- The climate variability in the area
- The value of diversity as a way of reducing risks, particularly in mountain ecosystems.