Submitted to: American Journal of Potato Research
Publication Type: Abstract Only
Publication Acceptance Date: January 26, 2001
Publication Date: N/A
With the emergence of new, more aggressive strains of Phytophthora infestans and release of new potato cultivars, evaluation of potato clones for resistance to late blight is necessary. Thirty-three potato clones (19 cultivars, 14 selections) were evaluated in 2000 for late blight resistance at six U.S. locations, along with eight late blight differentials. The US-8 strain of P. infestans was present at all locations except NY, which had the US-11 strain. Percent infected foliage was recorded at approximately weekly intervals following the onset of disease at each location. Area under the disease progress curve (AUDPC) was calculated. Clones were ranked for mean AUDPC within location and the non-parametric stability statistics, mean absolute rank differences and variance of the ranks were analyzed for phenotypic stability. There were significant genotype x environment interactions on the variance of the ranks of these clones. Only one clone, Q237-25, made a significant contribution to this interaction. In agreement with results from previous years, genotype x environment interactions on the rankings of AUDPC appear to be minimal for most clones evaluated: where significant, only a few clones account for the interaction.