Assessment of variety tolerance to potato cyst nematode (PCN) damage (2015-2018)

The provision of PCN tolerance information on new potato varieties is constrained by the difficulties of obtaining consistent information from field trials. Previous field-based assessments (2005-2006 and 2010-2012) had produced variable results. Potato plants grown in 1 tonne boxes, with and without introduced PCN inoculum, were studied to determine if the system would generate consistent information on variety tolerance. The ultimate aim was to assign new varieties into tolerance categories as used in the PCN management tool (PCN calculator). The system was tested over 4 seasons.

• 2015

An initial scoping study was carried out using four varieties. In the PCN-inoculated boxes, a small net “teabag” containing cysts of Globodera pallida (Pa2/3) was placed beneath each tuber. The behaviour of tolerant (Cara) and intolerant (Maris Peer) control varieties was as expected. Two test varieties were included (Markies, Melody) on the basis that they had produced variable results in previous (2010-2012) field-based trials to assess tolerance.

• 2016

The control (Cara, Maris Peer) and test varieties (Markies, Melody) from 2015 were included in the study and a further 8 varieties with reported resistance to PCN (G. pallida) were also evaluated (Lanorma, Divaa, Performer, Innovator, Camel, Eurostar, Arsenal, Panther). All the resistant varieties showed Pf/Pi values less than 1, as expected, but all appeared intolerant to varying degrees.

• 2017

Early flooding of the boxes coupled with rainfall in 2017 resulted in poor initial growth which was not recoverable. The trial was abandoned and repeated in 2018.

• 2018

The varieties included were Cara, Maris Peer, Melody, Markies, Lanorma, Alcander, Performer, Innovator, Camel, Eurostar, Arsenal and Panther. Despite the plants achieving good growth, the test did not confirm previous results and there were no significant effects of PCN inoculation on yield or tuber number. It was concluded that the approach has proved too erratic to be considered as a future routine method for tolerance evaluation/updating the PCN calculator.

To evaluate a semi-field based method to assess varietal tolerance to potato cyst nematode, G. pallida.