Conserving the genetic diversity of Bolivian wild potatoes

Cadima Fuentes, X.


Abstract thesis Ximena Cadima Fuentes (to be defended on 8 Dec 2014):

Conserving the genetic diversity of Bolivian wild potatoes

The wild relatives of potatoes (Solanum sect. Petota) form the genetic reservoir for the improvement of the cultivated potato. Bolivia harbours 39 wild taxa of these wild potatoes, 21 of which are endemic species. This study aimed to evaluate to what level the current ex situ and in situ management efforts have conserved the genetic diversity of Bolivian wild potato species, and what recommendations can be formulated for improvement.

The current conservation status of Bolivian endemic wild potato species was assessed using both the globally accepted IUCN criteria and a methodology developed within the framework of the UNEP/GEF-Crop Wild Relative Project (CWR Project). These two methods led to different estimates of threat status for some of the species. Spatial analysis allowed to distinguish eight priority areas for in situ conservation of the 21 Bolivian endemic wild potato species. These areas represent a high concentration of endemic species and have a relatively low level of threat, but only one of them has a conservation status. This is a first step to direct the conservation efforts for wild potato species.

The genetic stability and diversity of material from different species under ex situ management was evaluated using microsatellite markers. The analysis was performed on accessions that went through a process of seed regeneration and multiplication during ex situ conservation. Genetic changes between different generations of ex situ germplasm were observed for the majority, but not all, of the investigated species. Potential causes of these changes include genetic drift and contamination resulting from human error during regeneration. The populations generated under ex situ conditions were also compared with re-collected in situ populations from the same location or area as the original collection. The results showed highly significant differences in all cases. Potential causes for these differences are changes during ex situ maintenance, sampling effects during collecting and in situ genetic change over time.

The integrated conservation of Bolivian wild potatoes requires a combination of in situ and ex situ activities. The principle recommendation for the in situ conservation is to move from a passive to an active approach, where conservation areas are prioritized, conservation plans are designed according to the type of area (protected area or agro-ecosystem) and local stake holders are involved. To make sure that ex situ material provides a good representation of the in situ genetic variability, regular re-collecting of species with few accessions (and therefore less variability), endangered in situ, and with known or potential favorable traits is necessary. Gene bank management procedures should follow the FAO gene bank standards and this should be monitored by a national body responsible for genetic resources. And finally, periodic monitoring of the genetic integrity should be implemented as part of good practices during regeneration procedures in order to detect possible changes and to help combat human errors.