Global Strategy for the Ex Situ Conservation of Potato - Global Crop ...

Documentation of evaluation data is not yet common practice and only a few potato
collections make these data available on the Internet.
Access through Internet
Passport data of the collections of wild species of 10 major genebanks are accessible
through the Internet (Table 12, Annex 4). The passport data of native cultivars of nine
collections, and cultivars of Solanum tuberosum spp. tuberosum of 15 collections (mainly
from Europe of which some holders did not complete the questionnaire) can also be found on
the Internet. (Tables 1 and 4, Annex 5)) Only few potato collections make characterisation
and evaluation data available on the Internet. However, as outlined in the paragraphs 5.4.8
and 5.6, various external stakeholders regularly make use of the evaluation data available in
the few on-line searchable databases.
5.4.6 Storage and maintenance (true seeds, tubers and in vitro).
Storage methods of potato germplasm depend on the type of germplasm. Wild relatives are
generally stored in the form of true seeds. Occasionally, native cultivars of the centre of
diversity are also stored as populations (true seeds), but this is no general practice in the
Latin American region.
Fifteen genebanks maintain ex situ storage facilities. Ten collections have long-term storage
facilities (-10 to –20 ºC) and nine have medium-term facilities for true seed conservation. Five
genebanks have both facilities for storing the base collections under long-term conditions
and keeping the active collections under medium-term conditions (Table 8, Annex 4). The
type of packaging of seeds in ex situ genebanks varies, several holders use aluminium foil
bags, but plastic, paper bags and bottles are used as well.
The native cultivars and germplasm of S. tuberosum spp. tuberosum cultivars are normally
vegetatively conserved; both seed potato and in vitro storage are employed.
The conditions of seed potato storage in cold rooms vary considerably. Temperature in the
cold stores varies from 2 to 14 ºC, 13 genebanks using 4 ºC facilities. The relative humidity in
the cold stores varies from 30 to 95 %; most common RH is around 70 %. Seventeen
genebanks have in vitro facilities for storage of cultivated material, whereas occasionally
accessions of wild species are stored in vitro as well. Cryopreservation is not a common
practice yet, although two genebanks conduct research to further develop this method further
for cloned material.
5.4.7 Health of potato germplasm
Distribution of potato germplasm, a common practice for most genebanks (see 5.4.8), is
regularly hampered by infection of the germplasm. Potato germplasm can be infected by a
substantial number of pathogens. The two most common and types of infection harmful for
distribution are:
! seed-borne viral diseases (only relevant for true seed collections), in particular PSTVd
and PVT, in Europe also PMT, PVR, APLV, APMoV;
! tuber-borne viral infections (most important viruses PLRV, PVS, PVX, PVY and PVM).
•
Five curators stated that collection have not been affected at all, whereas in 17 genebanks
germplasm has been infected to some extent (Table 9, Annex 4). Tuber infection is
mentioned particularly, only five genebanks mentioning problems with seed-borne diseases.
The limited reporting of seed-borne diseases is partly the result of quarantine regulations,
prohibiting movement of germplasm without a certificate, but also because not all collections
screen for such diseases, which may result in under-reporting.
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