Laboratory Testing

In addition to conducting inspections to certify potato seed, PCAN operates a USDA-accredited laboratory located in Alliance, Nebraska to serve the needs of Nebraska’s seed potato growers. PCAN personnel conduct tests to identify diseases using the latest ELISA and PCR technology. The staff at PCAN ensure that these services are provided in an efficient and timely manner. The purpose of this laboratory is to aid growers in providing customers with quality-assured seed.

Commonly asked questions regarding laboratory testing and procedures

  • Who collects leaf samples for summer serological testing?
    Growers are responsible for colleting leaves for serological testing.
  • How many leaves should be collected for summer serological testing per acre for Nuclear Generation lots?
    One leaflet at random from single plants with a minimum of 10, 15, 25, or 50 leaves dependent upon lot size.
  • How many leaves should be collected for summer serological testing per acre for lots Generation 1-5?
    • One leaflet at random from single plants with a minimum of 50 leaves for lots 0-5 acres in size.
    • One leaflet at random from single plants with a minimum of 100 leaves for lots 5-10 acres in size.
    • One leaflet at random from single plants with a minimum of 200 leaves for lots 10-20 acres in size.
    • One leaflet at random from single plants with a minimum of 400 leaves for lots greater than 20 acres in size.
  • What tests are required for seed entering Nebraska from other states?
    PVY, PVX, PVA, PVS, PVM, Clavibacter michiganensis, Pectobacterium atrosepticum, and PLRV.
  • How many leaves are tested per well for an ELISA test?
    Leaves are bulked at 10 leaflets per well.
  • Prior to in-vitro production, what tests are required for Prenuclear lots?
    PVA, PVS, PVM, PVX, PVY PLRV, PLV, PMTV, AMV, TRV, PSTVd, Bacteria Ring Rot and Black Leg shall be run on each clone and documented. If the PCAN laboratory is not available for services, a PCAN-accepted laboratory can be utilized.
  • What is meant by “latent variety” and what are some examples of latent varieties?
    Some potato varieties exhibit mild or no PVY symptoms. These varieties are termed “latent.”  Examples of latent varieties include Russet Norkotah (and strains), Prospect, and Shepody.  As a precaution, PCAN conducts latent virus testing on all russet-skinned varieties.
  • Does PCAN test for potato virus x (PVX) and potato virus s (PVS)?
    PCAN tests for PVX and PVS, but the presence of these two strains is not a cause for rejection or loss of seed class/generation.
  • When do summer virus tests occur?
    Approximately six to eight weeks after planting.