Browsing by Subject "Phytophthora infestans"

Late blight, caused by Phytophthora infestans (Mont.) de Bary, is considered the most devastating disease in potato (Solanum tuberosum L.) production worldwide. Control methods involve mostly the use of fungicides, which are costly and are under political pressure for reduction in Europe. Potatoes from the major potato cultivar in Sweden, King Edward, previously stacked with three resistance (R) genes (RB, Rpi-blb2 and Rpi-vnt1.1) were tested in a local Swedish field, with spontaneous P. infestans infection over three seasons to evaluate the effectiveness and stability of the resistance on leaves. In addition, testing of resistance was done in both in leaves and tubers. Field results demonstrated that the 3R stacked into the cultivar King Edward, showed practically full resistance to infections of P. infestans, with no difference to fungicide use. Moreover, the resistance was effective in both leaves and tubers. The results reveal the 3R potatoes offer a functional field resistance, that could, alone, reduce the total use of fungicides in agriculture by several percent in Sweden, in an event of modifications in the EU legislation.

Potato (Solanum tuberosum L.) is the world's third most important food crop, and its biggest threat is late blight caused by the fungus Phytophthora infestans (Mont.) de Bary. Although plant breeding has been aimed at developing resistant varieties, the use of fungicides is still the main control method. Breeding has the potential to produce functional and sustainable varieties, but its slowness and the adaptive nature of the pathogen make development challenging. Along with breeding and fungicides, different management practices, and prediction and monitoring models based on understanding the epidemiology of the pathogen and the combined effects of weather conditions, are means to develop more sustainable potato cultivation. In Finland, the Potato Research Institute conducts variety testing of potatoes. In the variety trials carried out in 2019 and 2020, the susceptibility of different potato varieties to late blight and the progression of foliar blight during the growing season were monitored. In addition to late blight resistance, an important criterion for the usefulness of the varieties tested is the yield level, which is examined in the trials. Differences were observed between the varieties in terms of foliar blight and the speed of its progression between the years. In both years, the foliar blight epidemic appeared later than expected in the trial area. The main reason for the delayed appearance of foliar blight was the weather conditions during the growing season. Late starch potato varieties proved to be the most resistant to foliar blight in the trials, and the weakest foliar blight resistance was observed in food potato varieties. Differences were also observed between the varieties in terms of 1000 tuber weights and tuber blight. Variety selection and weather conditions during the growing season have a significant impact on late blight pressure and the amount of damage caused. The most important characteristic of a variety is the yield, which was not measured in the experiments. Variety research conducted in Finland is important because the late blight resistance and agronomic characteristics of varieties coming from mainland Europe may not necessarily correspond to the information provided by the breeder in Finnish conditions. In the future, the development of integrated plant protection will play an increasingly important role in controlling P. infestans epidemics, as single actions will not provide sustainable solutions.