Cooperation 88, A Short-day Potato Cultivar Parented New Long-day Potato Cultivars with Stable Field Resistance to Late Blight (Phytophthora infestans)

The cultivar Cooperation-88 (C88), developed from the International Potato Center’s germplasm, bred in the Philippines and selected in Southwest China, has resistance to late blight, PVY, and PLRV. It is, however, a short-day cultivar and unsuitable for growing conditions in Canada. In 2015 the Canadian Private Potato Breeders Network (CPPBN) made reciprocal crosses between C88 with long day cvs Prospect and Shepody. C88 functioned as both male and female in the trial. Evaluations of progeny of the crosses indicated that some clones inherited resistance to late blight while producing high yields of tubers under long days. This finding reveals the acceptable heredity of resistance in a potato breeding program when a short-day cultivar is crossed with two different long day cultivars. This study meets the collaborative goal of the CPPBN to develop new potato varieties with durable resistance to late blight.