2019 Annual Meeting

BRR Testing

At the meeting, it was mentioned that the PCAN lab is now ready for bacterial ring rot testing upon completion of the 2019 growing season.  This is a very important service offered by PCAN, and both Maria Burney and Adam Winchester have taken the proper steps to learn the real-time PCR procedure.  Both Adam and Maria traveled to Idaho and spent time with Sherri Laug at the Idaho Crop Improvement Association, with Adam spending an additional three days at the lab of Amy Charkowski of Colorado State University to further become proficient in real-time PCR.  Furthermore, last February the lab was officially accredited by the USDA.  With help from our shipping point inspectors, we expect 2019 to be a great year for BRR testing.

Field Inspections and Summer Virus Testing

Currently, we are just finishing second inspections and are preparing for final inspections.  Overall, it is been a good season with limited virus detected. 

Remember, when shipping leaves to the PCAN office that it is always a good idea to leave the tops of the Ziploc bags slightly open, or to include holes in the bags.  This limits spoilage of the leaves and makes testing easier. 

ELISA tests will be conducted on all latent varieties for PVY.  This includes all russet varieties and Shepody.  PVY, PVX, PVA, PVS, PVM, CMS, PLRV and Patro tests are required for all lots entering Nebraska from other states.  These tests will also be conducted on all nuclear lots. 

State of the Industry

CWT of seed potatoes shipped continues to rise every year, as indicated in Figure 1.

Figure 1. XXXXX

Nebraska seed growers continue to express and interest in shipping seed with a Green Tag. This is to make inspections easier, and to ship seed across state lines, while keeping seed within the same operation. 

Russet Norkotah and its accompanying strains remain the most popular russet varieties with Nebraska seed growers, with 929.22 acres planted in 2018, though this was a decrease of 261.09 acres from 2017.  Overall, Frito-Lay varieties are the most popular among all types with 3,061.34 acres planted in 2018, an increase of 200.64 acres from 2017. 

Virus Management Plan

A new method to detect Potato Mop Top Virus (PMTV), Tobacco Rattle Virus (TRV) and the various necrotic strains of PVY will be implemented by PCAN personnel starting fall of 2019.  If a suspected diseased tuber is discovered at either shipping point or in storage, the specimen will be kept.  A further 200-tuber sample (which includes the specimen) will be cut to determine the percent incidence of virus.  If virus is less than 0.5% of that sample, then the lot is eligible for certification/recertification.  If the sample is above 0.5%, but less than or equal to 2.0% then the lot is eligible for certification/recertification only a lab test demonstrates that the lot is less than or equal to 0.5% PMTV, TRV or PVY.  These methods were developed by the USDA in conjunction with various certification agencies across the country.   

Experimental Post-Harvest Test Trial and PCAN Sampling Requirements

Currently, no significant changes will be made to the methodology used by PCAN to break dormancy for the post-harvest tests (PHT).  The focus of the 2019 season will be detecting alternative methods to break dormancy on several varieties which have not emerged sufficiently in recent years to give us a good reading for the winter grow-out.  PCAN will be looking at five different treatments which alter the ways in which PHT seed is stored and treated with gibberellic acid/bromoethane.  These treatments will be applied to three different varieties. 

If successful, PCAN will use the new method(s) only on the varieties that are receptive to the treatments.  It has taken us many years, and much trial and error to develop our current methods to break dormancy.  This trial, hopefully, will make our PHT that much better.

The number of tubers required by PCAN for PHT is listed below:

  0-1 acre: 125 tubers

            2-10 acres: 250 tubers

            11-70 acres: 500 tubers

            71+ acres: 1,000 tubers

These requirements will not change in 2019.  Idaho, Michigan, Oregon, Colorado and New York have all accepted PCAN requirements.  Wisconsin and Michigan will require more testing, however.  Since the importing state is often not known until following harvest, and after the PHT is underway, PCAN will accept the additional seed to be tested using the direct-tuber test method.

PCAN Update

The new website is now complete.  This newsletter with be the first of two bi-annual newsletters to be included on the website – one during the winter following the Post-Harvest Tests, and another, such as this, following the Annual Meeting.  Maria and Adam will be attending several different conferences in 2019/2020.  We will report on these meetings in the winter newsletter.