The PRI disease resistant apple breeding program is cooperative among Purdue University, Rutgers, The State University of New Jersey, and the University of Illinois. Current program leaders are Jules Janick, Purdue University, Joe Goffreda, Rutgers University, and Schuyler Korban, University of Illinois.
The program was initiated in 1945 to breed apples resistant to scab caused by the fungal pathogen Venturia inaequalis. A complete history of the program can be found in the article entitled: Breeding Apples for Scab Resistance: 1945-1990. General information on apple breeding can be found in a review article entitled Apples (this is a pdf file) which appeared in a three volume work entitled Fruit Breeding edited by Jules Janick and J.N. Moore.
Up to the present time over 1500 selections have been made of which 44 have been released for advanced testing. Advanced selections are called co-ops to highlight the co-operative nature of the program and a number of them have been named and patented.
Cultivars (varieties) named by PRI include Prima (1970), Priscilla (1972), Sir Prize (1975), Jonafree (1979), Redfree (1981), Dayton (1988), Williams Pride (1988), Enterprise (1993), GoldRush, (1993), PristineTM, (1994), Scarlett O'HaraTM (2000), SundanceTM (2004), Pixie CrunchTM (2004), and CrimsonCrispTM (2006) .
Joint releases include; McShay (1988) released in cooperation with Oregon State University, Priam (1974)and Juliet (1999) released in France; Primiera (1995), released in Italy; Primivera (1996), released in Quebec, Canada; and Constance (1995) released in Germany by an organic grower. Nambu (1994) is a PRI selection that was released without authorization in Japan. Viking (1969), released in Wisconsin, is a PRI selection but proved to be scab susceptible.