Screening South American potato landraces and potato wild relatives for novel sources of late blight resistance

Authors: PEREZ, WILMER - International Potato Center; ALARCON, LESLY - Universidad Nacional De Piura; ROJAS, TANIA - La Molina National Agrarian University; CORREA, YANINA - Pedro Ruiz Gallo National University; JUAREZ, H - Consultative Group On International Agricultural Research; ANDRADE-PIEDRA, JORGE - International Potato Center; Anglin, Noelle; ELLIS, DAVE - International Potato Center

Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2022
Publication Date: 1/24/2022
Citation: Perez, W., Alarcon, L., Rojas, T., Correa, Y., Juarez, H., Andrade-Piedra, J., Anglin, N.L., Ellis, D. 2022. Screening South American potato landraces and potato wild relatives for novel sources of late blight resistance. Plant Disease. 106(7):1845-1856. https://doi.org/10.1094/PDIS-07-21-1582-RE.
DOI: https://doi.org/10.1094/PDIS-07-21-1582-RE

Interpretive Summary: Late blight disease was responsible for the great Irish potato famine in the mid-1800s and is still a significant disease affecting potato. Breeders and commercial growers desire novel strategies and new approaches to help battle late blight disease because it has the potential to lead to total crop failure. Management strategies to reduce yield loss and food insecurity arising from late blight are greatly needed especially in areas with little access to agricultural inputs (i.e-fungicide). Thus, an ARS scientist and international collaborators set out to evaluate 508 individual accessions from the International Potato Center's genebank for resistance to late blight disease. The samples evaluated included both cultivated and wild material. The majority of the cultivated material (73%), after being challenged with the pathogen, was observed to be susceptible to late blight disease. However, twelve accessions derived from nine wild species demonstrated low susceptibility to late blight disease. Overall, this study revealed new, novel sources of resistance from wild and cultivated potato species, some of which had not been previously evaluated for reaction to late blight disease. The new sources of resistance identified from this study can now be used in breeding programs for developing potato varieties that can grow in areas with the late blight pathogen.

Technical Abstract: Late blight (LB) caused by the oomycete Phytophthora infestans is the most important biotic constraint for potato production worldwide. This study assessed 508 accessions (79 accessions of wild potato species and 429 landraces from a cultivated core collection) held at the International Potato Center (CIP) genebank for resistance to late blight under greenhouse conditions. One P. infestans isolate belonging to the EC-1 lineage, which is currently the predominant type of P. infestans in Peru, Ecuador, and Colombia, was used in the whole plant assays under greenhouse conditions. New sources of resistance to late blight (LB) were found in accessions of Solanum albornozii, S. andreanum, S. lesteri, S. longiconicum, S. morelliforme, S. stenophyllidium, S. mochiquense, S. cajamarquense, and S. huancabambense. All of which are species that are which are endemic to South America, and thus, could provide new, novel sources of resistance to potato breeding programs. The high percentage (73.25%) of susceptible potato landraces to late blight in our study suggests the importance of implementing disease control measurements, including planting susceptible genotypes in less-humid areas/seasons or switching to genotypes identified as resistant. A high risk of genetic erosion in potato biodiversity exists in high altitudes in the Andes due to susceptibility to late blight susceptibility of the native landraces and further the documented climatic change occurring in the Andes favoring the development of LB in the potato growing regions.