Effect of Different Genotypes of Phytophthora infestans (Mont. de Bary) and Temperature on Tuber Disease Development

Abstract

The interactions of different cultivars/Advance Breeding Lines (ABL) of potato with different genotypes of the potato late blight pathogen (Phytophthora infestans) at three storage temperatures on tuber late blight development were evaluated. The contribution of the medullar storage tissues was assessed rather than the periderm and outer cortical cell tissue. Tuber late blight severity measured as tuber darkening [mean Relative Average Reflectance Intensity [RARI (%)] generally increased with temperature. There was little difference in tuber late blight development between 7°C and 10°C treatments and in some combinations significantly more tissue darkening developed at 7 than at 10°C but little or no development occurred at 3°C. Resistance in tubers was observed only in Torridon andStirling and to some extent Jacqueline Lee, but the cultivar Missaukee had weak tuber resistance. The US-8 genotype isolates were the most aggressive in tubers in most years causing rapid and significantly more tuber damage than any other genotype of P. infestans and similar to the US-6, US-10 and US-14 isolates used in 2006.Resumen Se evaluaron las interacciones de diferentes variedades y líneas avanzadas (ABL) de papa con diferentes genotipos del patógeno del tizón tardío (Phytophthora infestans) a tres temperaturas de almacenamiento para el desarrollo del tizón tardío en tubérculo. Se analizó la contribución de los tejidos medulares de almacén en vez del peridermo y de tejido celular cortical más externo. La severidad del tizón tardío del tubérculo, medida como el oscurecimiento del tubérculo [media de la intensidad del promedio relativo de refractancia [RARI (%)], generalmente se incrementó con la temperatura. Hubo poca diferencia en el desarrollo del tizón tardío del tubérculo entre los tratamientos de 7 y 10°C, y en algunas combinaciones se desarrolló mayor oscurecimiento de tejido significativamente a 7 que a 10°C pero no se presentó a 3°C. La resistencia de los tubérculos se observó solo en Torridon y Stirling y hasta cierto punto en Jacqueline Lee, pero la variedad Missaukee tuvo débil resistencia de tubérculo. Los aislamientos del genotipo US-8 fueron los más agresivos en tubérculos en la mayoría de los años causando más daño en tubérculo rápida y significativamente que cualquier otro genotipo de P. infestans y similar a los aislamientos US-6, US-10, y US-14 usados en el 2006.

Tuber Blight Development in Potato Cultivars in Response to Different Genotypes of Phytophthora infestans

“…US‐8 isolates also proved more aggressive on potato tubers causing faster appearance of tuber rot symptoms than isolates observed previously (Kirk et al. , ). The US‐8 genotype quickly became predominant in potato cropping systems following its first detection in 1989 in north and central Mexico (Goodwin et al.…”

“…Tuber blight importance has been identified previously as a critical factor in storage and season‐to‐season transmission (Johnson and Cummings ; Kirk et al. , ; Nyankanga et al. ).…”

“…Different cultivars also vary in these resistance components, and there is variation in the aggressiveness of P. infestans genotypes (Kirk et al. , , ). Potato breeding has focused on resistance of foliage with little effort on tuber blight resistance.…”

“…Potato breeding has focused on resistance of foliage with little effort on tuber blight resistance. This trend has changed over time due to the importance of tuber blight that can result in storage rot losses and transmission from season to season through seed (Johnson and Cummings 2009;Kirk et al 2009Kirk et al , 2010. Therefore, it is important to compare tuber disease development caused by isolates of new genotypes of P. infestans with isolates of the existing genotypes to commonly produced cultivars and those with known tuber resistance to P. infestans.…”

Phenotypic and genotypic variation in Michigan populations of Phytophthora infestans from 2008 to 2010

“…The severity of tuber tissue infection was expressed as relative average reflective intensity (RARI). RARI (%) has a minimum value of 0 (no symptoms) and maximum value of 100 (black tuber surface), as previously described (Kirk et al ., ; Rojas et al ., ). Data were analysed by anova using jmp v. 10.0.…”