Red Delicious
The Red Delicious is a clone of apple cultigen, now comprising more than 50 cultivars, first recognized in Madison County, Iowa, in 1880. According to the US Apple Association website, it is one of the fifteen most popular apple cultivars in the United States.
York Imperial
In 1820, Quaker nurseryman Jonathan Jessop (also Jessup) developed this variety of apple on his "Springwood Farm" near York, Pennsylvania, United States, from grafts of a tree from John Kline's farm at Hellam, Pennsylvania. Some sources have reported that Jessop had noticed school children selectively choosing leaf-covered apples that were in a well preserved in the early spring, and later grafted another variety onto it. Though lop-sided, this new cultivar quickly became popular because of its taste and long keeping properties—which were especially important in the era before refrigeration. This cultivar was originally known as 'Jonathan’s Fine Winter' (sometimes reported as 'Johnson’s Fine Winter'), after Jonathan Jessop. Some sources credit John Kline of Hellam and some say it was William Johnson, nearer to York. Kline was reported to be the one who found the apples under the leaves and took them to Jessop, yet Jessop got the credit for the continued development of the apple. Scientific publications credit the long keeping trait to the density of the apple.