Neal Peterson and Harry Swartz germplasm collection (1981)
Screening of about 1500 accessions at the University of Maryland
Open pollinated seedlings from collections of Buckman, Zimmerman, Hershey, Allard, the Blandy Experimental Farm, Ray Schlaanstine, and some modern cultivars
Pawpaw Regional Variety Trial initiated in 1994 by R. Neal Peterson and Desmond Layne
10 cultivars and 18 PPF advanced selections