The breeding program started in 1980, with the aim to obtain new cultivars more productive and with superior fruit quality; the following interesting characters were selected among the cultivars of the variety testing trial: medium-late leafing time, homogamy, high percentage of fruitful lateral buds, early bearing, resistance to X anthomonas jugl and is, reduced tree size, high kernel-shell ratio, high quality of nut and kernel.
During 1980–1983, the following controlled crosses have been made:
|Sorrento x Serr||Sorrento x Gustine|
|Sorrento x Payne||Sorrento x Midland|
|Sorrento x Pedro||Hartley x Sorrento|
|Sorrento x Tehama||Franquette x Sorrento|
|Sorrento x Chico||Franquette x Serr|
Till now, a total number of 2000 seedlings has been obtained.