OSU-HAREC Commercial Potato Seed Lot Trial
Jesika Holcomb, OSU-HAREC
Introduction
The Hermiston Experiment Station has been conducting the Seed Lot Trials for over 40 years in
an effort to assist local potato growers and understand potato seed disease issues and maintain
quality control. The Seed Lot Trial is an important tool for local potato growers to submit a
sample of each seed lot to be grown under controlled conditions at HAREC and then be
evaluated by professionals to determine any issues of concern. In addition the Seed Lot Trial
provides an independent opportunity to determine when issues arise and whether the problem is
seed related.
Percent Composition of Seed Lot Trial 2010-2012
%30
25
20
15
2010
10
2011
5
2012
0
Percent of Seed Lots from each Region 2010-2012
%30
25
20
2010
15
2011
10
2012
5
0
Canada
CO
ID
MT
ND
OR
Other
WA
Disease Issues in the Seed Lots
Percent of Seed Lots Expressing Symptoms of Mosaic, Leaf Roll and Black Leg 2010-2012
Disease
PVY (Mosaic)
PLRV
Black Leg
2010
34.4
0
5.2
2011
21.5
0
4.7
2012
40.7
0
0.93
Percent of Seed Lots of each Cultivar Expressing Mosaic Symptoms 2010-2012
% 12
10
8
2010
6
2011
4
2012
2
0
Alturas
Burbank Norkotah
Other
Premier
Ranger
Shepody Umatilla
Percent of each Cultivar with > 5% Mosaic Infection 2010
2010-2012
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
2010
2011
2012
Alturas
Burbank Norkotah
Other
Premier
Ranger
Shepody Umatilla
PVY Strain
train Breakdown by Cultivar 2011
In 2011, a total of 83 mosaic samples were collected from 17 seed lots that originated from 6
states and 2 Canadian provinces. Of the 83 samples collected, 88% were confirmed to have
PVY. The majority of the PVY positive plants were infected with the PVYO strain (71.4%). The
remaining plants were infected with either PVYNTN (17.1%) or PVYNO (11.5%) strains.
While PVYO reduces yield, PVY “N” strains can also reduce tuber quality.