Katy apple is a Swedish variety raised in 1947 at Balsgard Fruit Breeding Institute, Sweden. Parentage is James Grieve and

Worcester Pearmain 'Worcester Pearmain' is an early season English cultivar of domesticated apple, that was developed in Worcester, England, by a Mr. Hale of Swanpool in 1874.

and it produces heavy crops of bright red fruit. Sugar 12%, acid 8.5 g/litre, vitamin C 6 mg/100g.Obst und Garten 10/2000

References

Apple cultivars Swedish apples {{apple-fruit-stub