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etween in-situ conservation efforts focusing on crop wild relatives and cultivated genetic
diversity relates to the inherent anthropogenic nature of the latter. Fundamentally, cultivated
genetic diversity cannot be maintained in-situ without its active management by man while
crop wild relatives are ideally left uninterrupted without human interference (e.g. habit
destruction) which would put at risk their long term survival (Heywood et al., 2007; Jarvis et al.,
2008; Maxted et al., 2008). It is doubtful that conservation perse motivates most farmers to maintain
high levels of potato genetic diversity. Nevertheless, there are indications that individual farmers
may accumulate and maintain diversity for “conservation” purposes. However, in general, farmerdriven
in-situ conservation can be seen as the outcome of livelihood strategies that actively use
and rely on crop genetic diversity (Brush, 2004).
In this study, farmer-driven in-situ conservation of potato, i.e. that which is being grown by
farmers, is investigated at different system levels from alleles, cultivars, and botanical species up
to agroecology as well as overarching links to seed and food systems. The dimensions of time
and space are inferred upon by taking into account both annual and longer-term spatial patterns
within the Andean environment. The thesis also aims to link the diversity found in farmers’ fields
and its temporal-spatial distribution to a series of farmer-based drivers, such as changes in land
use, and external drivers, e.g. biotic and abiotic stress and markets. Components of farmer-driven
in-situ conservation are “mirrored” against each other to gain insights into their relationships,
e.g. formal versus indigenous biosystematics and in-situ versus ex-situ conservation. The study
of these different elements of farmer-driven in-situ conservation of the potato is multidisciplinary
in its basic conceptual approach and integrates different methodologies and tools while focusing
on the selected dimensions described below.
1.2.1 Inventory of diversity
While distribution patterns of cultivated potato species are well defined (Correll, 1962; Hawkes,
1990; Hawkes and Hjerting, 1989; Huaman and Spooner, 2002; Ochoa, 1990, 1999, 2003; Sauer,
1993), the same is not true for the fine grained scale of cultivar diversity. Andean farmers in Peru
are estimated to conserve up to 3,000 distinct native cultivars based on passport data from the
world potato genebank held at the International Potato Center. However, beyond the general
notion that cultivar diversity is particularly high in the central and southern Peruvian Andes,
little is known about the contemporary distribution of infraspecific diversity within specific
regions. The characterization and comparison of populations of native cultivars being maintained
through farmer-driven in-situ conservation is important in order to define the “object of
conservation” (Brush et al., 1995). This is affirmed by Maxted and Hawkes (1997) when they point
out that “as a matter of urgency, a chain of genetic reserves to conserve cultivated potatoes
should be established throughout the Andes in areas with high levels of genetic diversity”.
Cultivar populations in the hands of farmers in Vavilov centers of crop origin and diversity
are commonly reported to be subject to genetic erosion resulting in the loss of alleles (Frank et
al., 2002; Harlan, 1975; Ochoa, 1975) and ongoing evolution leading to the gradual creation of
new genotypes or alleles (Altieri, 1987a, 1987b; Mann, 2004; Maxted et al., 1997; Vavilov, 1992).
The occurrence of genetic erosion, when defined as the loss of alleles and gene complexes from
in-situ populations, is generally difficult to substantiate because of a lack of baseline data needed
for comparison over a sufficient timeframe (Brush, 2004). Therefore relatively few studies have
been able to provide quantitative evidence to sustain or reject the occurrence of genetic erosion
(e.g. Huang et al., 2007). Differences between the contents and structures of genebank collections
and contemporary cultivar populations in the hands of farmers, from the same geographical
origin, are little known (for an exception concerning wild potato species see Del Rio et al., 1997).
1.2.2 Farmers’ classification
A better understanding of the interface between researcher and farmer systems of
24 Potato diversity at height: Multiple dimensions of farmer-driven in-situ conservation in the Andes