Oca Diversity and its Conservation Status

The presentation expounded upon Emshwiller’s study of oca distribution and diversity, with the surprising finding that most oca clones are very narrowly distributed, which would signal a significant threat to its conservation.

Ethnobotany is the wide-ranging study of interactions between human cultures and plants, and Dr. Emshwiller’s research over the years has concentrated upon the history of oca domestication, and the implications of human influence on the conservation of the diversity of this crop and its wild relatives. Emshwiller, who has collaborated with CIP for over 15 years, divulges that the overall goals of her research “have always been to provide information to help conserve the diversity of both cultivated oca and its wild relatives.” The focus of her research over the years has been based on understanding the diversity of oca, its geographical origin, and what wild species gave rise to the domesticated crop.

While oca may not be considered as globally important a crop as potato or sweetpotato, Emshwiller believes it has huge regional importance to rural Andean farmers who practice traditional crop rotation and intercropping. For these farmers, oca is useful not only as an added source of nutrition, but also in ensuring the utility of cropland for other roots and tubers. The continued diversity of genetic lines of oca, which is grown throughout the Andes, is therefore vital to ensuring the region’s biodiversity.

image_blogimageDr. Emshwiller’s presentation revealed the findings of her project as a pilot using new methods to map the genetic diversity of oca and assess its conservation status. The project focused upon studying how the so-called seed flows of exchange between farmers have affected the distribution of clones throughout the Peruvian Andes. The project conducted genetic studies of oca collected in communities throughout Peru. While linkages in oca were made along traditional language networks and areas connected topographically, Emshwiller was shocked to find how narrowly distributed the clones were. “Most of the varieties collected by the study were particular to single localities,” noted Emshwiller, “If the same varieties were found in different localities, they tended to be very close together.” While further research and sample collections are necessary to confirm her research, these results have strong implications towards the safety of the conservation of the diversity of oca, both in situ and ex situ, throughout the Andean highlands.

In some areas of Peru, Emshwiller claims that oca diversity is already dying out. Having conducted wide-ranging studies over the past 20 years, she has witnessed the wide scale recession of oca in certain areas of the country, and its complete disappearance from other areas. Causes vary from the destruction wreaked by Maoist terrorists, to the introduction of intensified dairy cattle farming. Emshwiller also notes that urban migration has left many elderly farmers to cultivate rare and perhaps unique varieties of oca without the chance of passing these practices down the generational line. The oca weevil, different from the potato weevil, is also apparently getting worse across Peru, although studies are still needed to confirm this.

Dr. Emshwiller’s research makes it clear that conserving the genetic diversity of oca is of growing importance, and that the ex situ conservation of germplasm in CIP’s genebank and in other centers such as the Peruvian National Institute for Agrarian Innovation (INIA) is vital to ensuring the continued existence of unique lines of genetic diversity. In situ conservation of oca is of equal importance and it is hoped that programs to promote the onsite diversity of oca can be implemented in the future.

In the meantime, Eve Emshwiller is working with the Genetic Resources sector at CIP to develop a gap analysis for oca. A gap analysis is an established conservation technique used to identify areas where selected elements of biodiversity are represented. By comparing these with existing in situ protected networks, the gap analysis identifies habitats, ecosystems and areas that need additional protection. This gap analysis of oca will also give CIP a better understanding of its own oca germplasm collection and what it may be missing.

Eve Emshwiller, who is a faculty member at the University of Wisconsin-Madison, was recently awarded a Fulbright Scholar grant, which will enable her to continue her research into wild oca in Bolivia in the coming future. Her current research would indicate that the unnamed wild, tuber-bearing oca found in Bolivia and another variety of wild oca found in northwest Argentina are the best candidates as the genome donors for domesticated oca. However, results are still equivocal, and further research is needed to determine exactly how and from where oca evolved into the odd and wonderfully diverse crop it is today.