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United States Department of Agriculture

Agricultural Research Service

Research Project: Developing Resistance to Potato Cyst Nematode as a Tool for Eradication

Location: Small Grains and Potato Germplasm Research

Project Number: 2050-21000-032-09-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 18, 2012
End Date: Aug 31, 2015

Conduct bioassays to evaluate the resistance of existing clones/cultivars in the potato breeding program to the Globodera pallida population originating from the Shelley, Idaho area.

The European Union protocol for resistance testing (The Council of the European Union, 2007) will be used to screen existing potato clones/cultivars for resistance. Experiments shall be performed in pots with soil temperatures during the experiment not exceeding 25ºC. The potato varieties ‘Desiree’ (internationally relevant) and ‘Russet Burbank’ (regionally relevant) will be used as standard susceptible control varieties in each test. Sante will be used as a standard resistant variety. In addition, differential potato clones from Scotland with resistance genes for G. pallida and/or G. rostochiensis will be included in the screening to allow genotyping of the resistance found. The Globodera inoculum (Pi) will consist of approximately 5 viable eggs or juveniles per ml of soil. Cysts used in experiments will be kept for at least four months at 4ºC, and have a viability of at least 70% as determined by Meldola Blue staining (Kroese et al., accepted). At planting, one sprouted potato eye plug will be planted into infested soil. There will be at least six replicates of each tested potato variety and the standard susceptible control varieties will be replicated 10 times. The duration of the experiment will be at least twelve weeks. At the end of the experiment, Globodera cysts will be extracted from soil using a Fenwick cyst extractor and the final population (Pf) determined by crushing cysts and counting eggs and juveniles. A multiplication rate of at least 20 (Pf/Pi) on the standard susceptible control variety shall be achieved for the test to be considered valid. The relative susceptibility of the tested potato clones/cultivars to the standard susceptible control variety will be determined as: Relative susceptibility (RS) = Pftest variety/Pfstandard susceptible control variety x 100% A set of approximately 23 breeding clones and cultivars will be screened for PCN resistance. All clones will be provided by the Aberdeen Breeding Program.

Last Modified: 05/28/2017
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