Potato Cultivars from the Mexican National Program: Sources and Durability of Resistance Against Late Blight

Abstract

The Mexican National Potato Program has produced several cultivars with high levels of field resistance. We evaluated the durability of resistance to potato late blight of a selection of 12 such cultivars using data from 1960 to the present. Data were extracted from the field notebooks located in the archives of the Mexican National Potato Program in the John S. Niederhauser Library in Toluca, Mexico. There was a trend indicating that field resistances to potato late blight of Mexican cultivars released between 1965 to 1999 were durable. At least two of the cultivars, namely 'Sangema' and 'Tollocan', have been grown on at least 4 to 5% of the potato acreage and over long periods of time without decay in levels of field resistance. Pedigrees of the 12 cultivars indicate that most of the field resistance was introgressed from Solanum demissum. Field resistance might also be derived from commonly grown land-race cultivars such as 'Amarilla de Puebla' and 'Leona'. These have been grown in Mexico since about the 1780s. They have the appearance of S. andigena-derived material but their genetic background is unknown.

Regional spore dispersal as a factor in disease risk warnings for potato late blight: A proof of concept

“…Spray treatments were applied maximally one day before the actual start of the critical period. SIMCAST's (Grunwald et al, 2000(Grunwald et al, , 2002 fungicide units (FU's) were used to determine the remaining level of fungicide protection. Blightdays as described by Skelsey et al, (2009) were used to determine critical days, days with sufficiently long periods of leaf wetness to support infection.…”

Comparación de la resistencia horizontal y vertical contra el tizón tardío de la papa en Toluca

“…Sin embargo, en la actualidad se sabe que los genes R están involucrados en todos los tipos de resistencia por lo que se está tratando de generar variedades con una combinación de varios genes mayores y menores, a lo cual se le ha llamado construir pirámides de genes (Adillah et al, 2010;Kim et al, 2012;Zhu et al, 2013). Esta estrategia se desarrolla actualmente con la ayuda de la ingeniería genética, pero algunas variedades viejas que poseen una combinación de genes mayores y menores, las cuales fueron generadas por métodos tradicionales en México y otros países, han demostrado que tienen una resistencia duradera (Grünwald et al, 2002;Rietman et al, 2012).…”

“…However, at present it is known that the R genes are involved in all types of resistance so it is trying to develop varieties with a combination of several major and minor genes, to which has been called build pyramids of genes (Adillah et al, 2010;Kim et al, 2012;Zhu et al, 2013). This strategy is currently being developed with the help of genetic engineering, but some older varieties that have a combination of major and minor genes, which were generated by traditional methods in Mexico and other countries, have shown to have a lasting resistance (Grünwald et al, 2002;Rietman et al, 2012).…”

“…Most of the potato varieties released in Mexico by INIFAP possess a combination of major and minor genes that confer resistance to P. infestans (Flores and Cadena, 1996;Grünwald et al, 2002;Rubio et al, 2005). His evaluation was carried out under field conditions in the Valley of Toluca, which has allowed select some cultivars with durable resistance, however, have not been compared with genotypes that have only minor genes.…”

“…Sin embargo, en la actualidad se sabe que los genes R están involucrados en todos los tipos de resistencia por lo que se está tratando de generar variedades con una combinación de varios genes mayores y menores, a lo cual se le ha llamado construir pirámides de genes (Adillah et al, 2010;Kim et al, 2012;Zhu et al, 2013). Esta estrategia se desarrolla actualmente con la ayuda de la ingeniería genética, pero algunas variedades viejas que poseen una combinación de genes mayores y menores, las cuales fueron generadas por métodos tradicionales en México y otros países, han demostrado que tienen una resistencia duradera (Grünwald et al, 2002;Rietman et al, 2012).Desde que Van der Plank (1963) describió los conceptos de resistencia horizontal y vertical, ha habido un interés constante en diferenciar la resistencia horizontal y vertical. La pendiente de la curva de infección, la etapa de desarrollo de las plantas en la que aparecen las primeras lesiones, la presencia de esporangios en las lesiones, y la reacción de hipersensibilidad en las hojas son algunos de los parámetros que se han utilizado para diferenciar los dos tipos de resistencia.…”