University Of Tasmania

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QPCR testing seed potato tubers for pathogens – what value for potato seed certification?

conference contribution
posted on 2023-05-23, 11:16 authored by Robert TeggRobert Tegg, Calum WilsonCalum Wilson
Utilising certified seed is an important principle in providing a potato crop with the greatest opportunity to grow to its full potential free of disease. Within Australia economically important tuber blemish diseases affecting potato tuber quality include Black scurf, Common scab, Powdery scab and Root knot nematode, caused by infections with the pathogens, Rhizoctonia solani, Streptomyces scabies, Spongospora subterranea f. sp. subterranea, and Meloidogyne spp. respectively. All of these pathogens may be carried on seed-tubers providing inoculum for disease in the subsequent crops, and are assessed in potato seed-tuber certification schemes world-wide. Typically seedlots are certified by visual subjective assessments of disease but recently developed quantitative polymerase chain reaction (qPCR) tools that detect and enumerate pathogen DNA provide an additional measure of seed tuber health. We compared both visual and qPCR assessments of potato seedlots passing through the Tasmanian potato certification scheme over a three year period. Further, selected tubers carrying tuber-borne inoculum loads of the three pathogens were grown in pathogen-free potting soil to establish whether the concentration of pathogen DNA from the tuber peel was associated with progeny crop disease. Outcomes suggest that visual assessment, in most circumstances provides an accurate measure of tuber seed health for certification; however qPCR was able to clearly differentiate difficult to distinguish diseases and identify levels of pathogen DNA present on symptomless tubers. Additionally, it was shown that planting tubers with high pathogen inoculum loads led to enhanced progeny disease compared to planting 'certified' tubers.


Horticulture Innovation Australia


Publication title

Acta Horticulturae




JR Schultheis






Tasmanian Institute of Agriculture (TIA)


International Society for Horticultural Science

Place of publication


Event title

XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes: International Symposium on Root and Tuber Crops: Sustaining Lives and Livelihoods into the Future

Event Venue

Brisbane, Australia

Date of Event (Start Date)


Date of Event (End Date)


Rights statement

Copyright 2016 The International Society for Horticultural Science

Repository Status

  • Restricted

Socio-economic Objectives

Field grown vegetable crops