Effect of different genotypes of Phytophthora infestans and temperature on tuber disease development of advanced breeding lines

Potato late blight, caused by Phytophthora infestans is limiting disease for potato production, and often affecting in early stages due to inoculum survival in the seed tubers. The objective of this study was to get seed tubers from advanced breeding lines (ABL) and challenge them with different genotypes of P. infestans at three different temperatures used in storage (3, 7 and 10C) in four production seasons. The results were analyzed as mean tuber disease response affected by components of isolates genotype, variety and storage temperature. Results showed that most of the varieties were resistant to US-1 genotype, regardless of the storage temperature and US-8 genotype was the most aggressive followed by US-14. It was also noticed that tuber resistant breeding lines were evaluated having little to no late blight infection. The ABL's differed in their resistance to the different genotypes of P. infestans, although the resistance has been increased, the disease response is still high. These results showed the importance of different components involved in the disease development and inoculum source, including the pathogens variability as an important component to take in advance. This study is an important approach to overcome new P. infestans genotypes equally or more aggressive than US-8 genotype.