"The first sour cherries planted in the university’s experimental plots were from seeds from the Central Siberian Botanic Garden in Novosibirsk. These were just beginning to fruit when Rick began work as a technician in 1971. They had low productivity and lacked winter hardiness. Asked to discard them, Rick took two home which he tried (unsuccessfully) to cross with sweet cherries. His goal: to develop a hardy, large shrub with large, high quality fruit.
Rick’s next crosses involved a collection of sour cherries, mainly from Europe, received from Les Kerr (who had worked on them for at least 20 years). All these were controlled crosses in the greenhouse with help from Rick’s kids on weekends. “It was a great botany lesson for them,” he says.
Rick crossed the best of these, ‘Kerr’s Easy Pick,’ with ‘North Star’, a sour cherry tree introduced from Minnesota. The result was ‘SK Carmine Jewel'." (Excerpted from an article by Sara Williams)