Evaluation of foliar resistance in potato to Phytophthora infestans based on an international field trial network

Abstract

During the period 2000-03, local potato cultivars in Estonia, Latvia, Lithuania, Poland and Denmark were tested for foliar resistance to Phytophthora infestans (late blight) in an international field trial network. Four standard cultivars were included in the trials: Sava, Oleva, Danva and Kuras. Primary disease-assessment data were entered into a common database, and parameters from the disease progress curves were calculated and made available on interactive web pages. A regression model, using relative area under disease progress curve (RAUDPC) values for cv. Oleva as a reference, was developed for the estimation of 1-9 scale values, where 1 = most susceptible. Standard deviations for the estimated 1-9 scale values and a nonparametric rank stability analysis of RAUDPC were used to evaluate the stability of resistance of the cultivars. Overall, the results showed stability of resistance for cvs Sava, Oleva and Danva, but not for Kuras. Use of the Internet-based Web-Blight service in this study facilitated comparison of results among countries for the level and stability of resistance. The estimated 1-9 scale values were similar to, or slightly lower than, those from official cultivar lists or from the European Cultivated Potato Database, especially for the more resistant cultivars. Possible reasons for discrepancies from different sources and locations are discussed. It is concluded that RAUPDC and the derived 1-9 scale values are useful for ranking cultivars for resistance to P. infestans , but this information is not detailed enough for use in a decision support system for late blight control.

The structure of mating type, metalaxyl resistance and virulence of Phytophthora infestans isolates collected from Latvia

“…For instance, in the vegetation period with favourable weather conditions for late blight development, tuber yield formation was interrupted two weeks earlier in an organic potato production field without any fungicide compared to in a conventional field where fungicide was applied (Skrabule, 2010). Late blight development depends on potato varietal resistance, the foliage of potato varieties with higher resistance were less damaged by late blight, as was also found in Denmark, Estonia, Poland, Lithuania and Latvia (Hansen et al, 2005). Thus,…”

The field resistance of potato cultivars to foliar late blight and its relationship with foliage maturity type and skin type in Brazil

“…The variables used to identify potato cultivar resistance to foliar late blight in the present trials are the same as those used by a number of other authors, including the area under the disease progress curve (Cadena-Hinojosa et al 2007;Flier et al 2003;Forbes et al 2005;Fry 1978;Grünwald et al 2000;Hansen et al 2005;Haynes and Weingartner 2004;Ojiambo et al 2000), the rate of disease progress (Fry 1978;Ojiambo et al 2000), the maximum disease severity (Cadena-Hinojosa et al 2007;Fry 1978;), the yield data (Cadena-Hinojosa et al 2007) and the number of epidemic days (Hansen et al 2005). In these papers, variables were analyzed individually over time, but in the present work all of the variables were simultaneously analyzed to obtain a more global and simplified interpretation.…”

Phenotypic Expression of Resistance to Phytophthora infestans in Processing Potatoes in Argentina

“…We attempt to begin rectifying that problem by employing a method proposed by Hansen et al (2005) and modified by Yuen and Forbes (2009). In our application of the method, the cultivar (Shepody) was used to anchor the scale to the RAUDPC, by giving Shepody a value of 8.…”

“…Hence, the objective of this study was to quantify resistance to both foliage blight and tuber blight in new processing cultivars and test for potential host by pathogen interactions in the field and greenhouse. Field data were converted to scale values with simple scaling of the area under the disease progress curve (AUDPC) following the general approach of Hansen et al (2005) with modifications proposed by Yuen and Forbes (2009).…”