Nuclear Stock

The Seed Potatoes (Scotland) Regulations 2000 requires that seed stocks derived in Scotland must originate from nuclear stock (in vitro pathogen tested microplants) produced by SASA. This ensures that the starting material is pathogen-free according to a programme of official testing for indigenous and EU-quarantine pathogens.

Nuclear stock can then be maintained by SASA, on behalf of potato breeders and the industry, as part of a collection of over 700 potato varieties or can be issued to approved micropropagation laboratories for maintenance and further multiplication. Microplants can then be grown in a pest free medium in a protected environment to produce mini-tubers (class Pre-basic TC) or can be grown in the field to produce class Pre-basic 1 tubers. Order forms and charges for SASA's micropropagation services can be found on the Nuclear Stock Documents page which also includes a list of those varieties in the collection which are not subject to Plant Breeders' Rights as well as the Nuclear Stock Unit questionnaire. Access to varieties which are subject to Rights requires the permission of the breeder or his agent.

For queries about nuclear stock, see the contact details on the Contacts - Potato Branch page.

The testing programme in nuclear stock production is outlined below:

EU-quarantine organisms

  1. Potato Spindle Tuber Viroid: return PAGE or cRNA probe. 
  2. Clavibacter michiganensis (ring rot): egg plant and immunofluorescence microscopy 
  3. Ralstonia solanacearum (brown rot): semi-selective medium and PCR.


ELISA: PMTV, PVX, PVY, PLRV, PVA, PVS, PVM, PVV, Tomato Black Ring Virus and Potato Latent Virus (non-indigenous virus)

Bioassay: a range of indicator plants are also inoculated to check for common and unusual viruses, and possible new strains of existing viruses and other potato pathogens

Indicator plants: Viruses detected

Capsicum annuum: AMV, PVX

Chenopodium amaranticolor: PVX, PVS, PVT,APLV, PMTV, PBRSV, TRV, AMV, AVB-0, TBRV, TMV

Chenopodium murale: PVS, PVT, AVB-0, APLV, PLV, PVM

Chenopodium quinoa: PVX, PVS, APLV, PBRSV, TMV, PVU, AMV, TBRV, TNV, TRV,

Datura metel: PVX, PVY, PVA, PVM

Nicotiana bethamiana: PMTV, PVA, PVV, PVT, PVX, PVY, PYMV, TSWV, TMV

Nicotiana bigelovii: APMV, APLV, WPMV

Nicotiana clevelandii: PVX, PVY, PVA, APMV, APLV, PVV, TRV, TNV, PVM

Nicotiana debneyi: PVX, PVY, PVS, PVM, PVA, PVY, PMTV, PLV

Nicotiana occidentalis-PI: PotL V, PVX, PVY, WPMV

Nicotiana tabacum (cv. White Burley): PVX, PVY, PVA, TSV, TMV, TNV, TRV, TBRV, PBRSV


Dickeya spp. and Pectobacterium spp. - enrichment and semi-selective medium or PCR