SEED POTATO QUALITY IMPROVEMENT

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0218734
• Project Start Date: Jul 1, 2009
• Project End Date: Jun 30, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF IDAHO
875 PERIMETER DRIVE
MOSCOW,ID 83844-9803

Performing Department
Plant Soil & Entomological Sci

Non Technical Summary
Some of the most important challenges that face the seed potato industry are the potato viruses such as potato virus Y (PVY) and potato leaf roll virus (PLRV). Significant developments have taken place over the last several years in our understanding of the potato virus Y complex (PVY) which is now made up of not only the PVYo (ordinary strain), but also includes the PVYn (tobacco veinal necrosis strain) and the PVYntn (potato tuber necrotic strain) variants. In addition, more and more previously unreported viral strains, probably recombinants, with new and unknown capabilities continue to be discovered within U.S. seedstocks. The impact of PLRV (and the serious "net necrosis" tuber symptom that it causes) was greatly reduced by the advent of systemic insecticides, such as imidacloprid, that effectively control the aphid vectors of the virus. While the amount of PLRV in Idaho seed lots has not rebounded to high levels, there appears to have been a small but steady increase over the last three years.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1310	1101	100%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1310 - Potato;

Field Of Science
1101 - Virology;

Keywords

pvy

plrv

potato mosaic virus

elisa

potato virus management

seed certification

Goals / Objectives
The overall objective of the proposed research is to bring about an improvement in the health and quality of Idaho seed potatoes. Within this overall objective, this Hatch project will concentrate on management of the potato mosaic virus complex, a disease problem that, with the advent of tuber necrotic strains of virus, has a high potential to cause serious quality losses. The research will concentrate on developing recommendations for managing the potato mosaic virus complex with possible certification recommendations as well as in-season and post-harvest management protocols.

Project Methods
A.) Investigate methods to better identify seed lots with high levels of virus and target them for removal from the seed system. Seed lots intended for recertification will be tested for the mosaic viruses during the winter test grow outs. This information will be shared with the seed producer with the recommendation that seed lots with mosaic virus levels greater than 0.25% not be planted for recertification. B.) Monitor the occurrence of PVYn, PVYntn and possible new strains or recombinants using ELISA and PCR techniques. Potato plants or tubers that test positive for PVYn will be sent to the laboratory in Moscow for further characterization using PCR. This investigation will concentrate on identifying strains of PVYn and ntn as well as new or recombinant strains. Expand the monitoring efforts to include screening for PLRV. C.) Identification of important non colonizing aphid vectors could help in the development of management procedures targeting vectors or taking advantage of vector behavior. This will be accomplished by the use of suction-type aphid traps in key locations in or near the seed potato producing areas at Tetonia, Rexburg, Ririe and Grace, ID and in a commercial production area at Pingree, ID. Traps will be monitored weekly during the growing season (May-September) and evaluated for the number of aphids trapped and the aphid species present.

Progress 01/01/13 to 09/30/13

Outputs
Target Audience: Potato seed and commercial producers, industry representatives, fieldmen, county extension faculty, seed certification officials Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? I attended the following meetings: Potato Association of America 97th annual meeting. Quebec City, Quebec, CA, June 28-August 1, 2013. PVY-Wide 6th annual meeting. Idaho Falls, ID, June 25-28. I was co-chair of this meeting along with A Karasev. WERA-89 Western Region Coordinating Committee on Potato Virus Control Annual Meeting. New Orleans, LA, March 14-15, 2013. How have the results been disseminated to communities of interest? Educational presentations were made and educational articles were prepared for trade journals and newsletters What do you plan to do during the next reporting period to accomplish the goals? Continue with the current methods of presenting seminars and workshops and preparing educational articles for trade journals.

Impacts
What was accomplished under these goals? After the percentages of PVY in Idaho seed potatoes had declined for each of the previous five years, the industry experienced another decrease last year. Fifty-four percent of Idaho seed lots tested free of PVY, the highest percentage since serological testing of all seed lots was instigated. Fully eighty percent of the seed crop was eligible for recertification.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Nolte, P. and J. Whitworth. The comparison of visual inspection vs ELSIA for determining the level of Potato Virus Y in post-harvest seed potato lots. Presented at the Potato Association of America 97th annual meeting. Quebec City, Quebec, CAN, July 28-August 1, 2013.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Nolte, P. The effect of Potato Virus Y on yield in three varieties: Latest information. Presented at the PVY-Wide 6th annual meeting. Idaho Falls, ID, June 25-28.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Nolte, P. The Effect of ELISA Winter Testing on PVY Levels in Idaho Seed Potatoes 2005-2012. Presented at the PVY-Wide 6th annual meeting. Idaho Falls, ID, June 25-28.

Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Thirty-five early generation seed lots, planted for recertification in Idaho, from various out of state and in state seed sources were sampled and tested with ELISA to determine actual mosaic virus content. A 400 leaf sample was tested to determine the actual percentage of mosaic that was planted. Fifteen varieties originating from seed sources in ID, MT, ND, NE, and Canada were represented. Only seven seed lots tested positive for PVY. None of the lots tested positive for potato leaf roll virus or for PVA Results from this survey has been presented to the industry in trade journal articles and in oral presentations. PARTICIPANTS: The Idaho Crop Improvement Association (ICIA), the organization that oversees seed potato certification for the State of Idaho, provided access to their seed potato winter grow out plots in Brawley, CA as well as information on the PVY content of seed lots produced in the trial. TARGET AUDIENCES: Extension presentations were performed for both commercial and seed potato producers throughout the year. Trade journal articles on PVY were prepared and published several times during the year. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
After the percentages of PVY in Idaho seed potatoes had declined for each of the previous four years, the industry experienced a slight increase last year. However, this slight increase in Idaho seed was only a fraction of the increases suffered throughout the rest of the US. Even with the increase, eighty-one percent of Idaho seed lots were still eligible for recertification. The percentage of the total number of seed lots that exceeded 10% PVY was only 4.3%. When calculated on the total seed acreage, the percentage that exceeded 10% PVY was only 3.5% of the acres planted.

Publications

• Nolte, P. 2012 Combatting PVY: Team of researchers developing management strategies. Spudman, 50:1 42-44.
• Nolte, P. 2012. Potato Virus Y Update: The most important virus disease of potato. Potato Grower Magazine, 41(3):59.
• Nolte, P. 2012. California Grow-Outs: Winter a busy time for seed certification officials. Potato Grower Magazine, 41(4):42-43.
• Whitworth, J., Hamm, P.B. and Nolte, P. 2012. Distribution of Potato Virus Y Strains in Tubers during the Post-Harvest Period. Am. J. Pot. Res. 89(2):136-141.
• Nolte, P. 2012. New Website Takes Dead Aim at Potato Virus Y. American Vegetable Grower, January 4, 2012.

Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Thirty-eight early generation seed lots, planted for recertification in Idaho, from various out of state and in state seed sources were sampled and tested with ELISA to determine actual mosaic virus content. A 400 leaf sample was tested to determine the actual percentage of mosaic that was planted. Fifteen varieties originating from seed sources in ID, MT, ND, NE, and Canada were represented. Only seven seed lots tested positive for PVY. None of the lots tested positive for potato leaf roll virus or for PVA Results from this survey has been presented to the industry in trade journal articles and in oral presentations. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The percentages of PVY in Idaho seed potatoes has declined for the fourth year in row with fully ninety two percent of the lots produced in Idaho eligible for recertification.

Publications

• Nolte, P. Potato Pointers: The New Face of Potato Virus Y. American Vegetable Grower. 58(112):57 December, 2010.
• Karasev, A. and Nolte, P. Taking Precautions: Keeping the Industry Clean from PVY. Potato Grower. 40(1):54-55 January, 2011.
• Nolte, P. PVY Management: Don't Plant a Problem. Potato Grower. 40(9):30 September 2011.

Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Thirty-eight early generation seed lots, planted for recertification in Idaho, from various out of state and in state seed sources were sampled and tested with ELISA to determine actual mosaic virus content. A 400 leaf sample was tested to determine the actual percentage of mosaic that was planted. Fourteen varieties originating from seed sources in ID, MT, ND, NE, and Canada were represented. Results from this survey has been presented to the industry in trade journal articles and in oral presentations. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
The percentages of PVY in Idaho seed potatoes has declined for the third year in row.

Publications

• Gray, S.M., DeBoer, S.H., Lorenzen, J., Karasev, A.V., Whitworth, J., Nolte, P., Singh, R.P., Boucher, A., and Xu, H. (2010) Potato virus Y: a significant and evolving threat to potato crops in the United States and Canada. Feature Article. Plant Disease 94, 1384-1397
• Nolte, P. Seasons Briefings: What's new with PVY Proceedings of the University of Idaho Winter Commodity Schools 2010.
• Nolte, P. 2009. Potato Virus Y Management for the Seed Potato Producer. Proceedings of the 44th Annual Montana Seed Potato Seminar. November 3-4, Helena, MT.

Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: In an effort to identify and remove any sources of these new virus strains from the Idaho seed system, my staff and I, with additional funding from the Idaho potato industry continued a survey of potato seed lots intended for recertification for PVY and PVYn. Thirty seed lots were surveyed. Information gathered during this survey has been shared with the affected growers. The end result has been a reduction in the number of seed lots rejected for recertification and in the total number of virus-infected plants that were detected in the winter seed potato grow out in California. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Four presentations to Idaho and Montana seed producers were given during the previous year. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Potato virus Y continued to decline in Idaho Seed lots for the third straight year.

Publications

• Nolte, P, JM. Alvarez and JL Whitworth. 2009. Potato Virus Y Management for the Seed Potato Producer. University of Idaho CIS Bulletin #1165.