The original tree was grown from a seed planted in 1956 by David Sturrock of West Palm Beach, Florida.

Sturrock had written in 1969 that it had been a cross of Edward and Pico,[1] but a 2005 pedigree analysis indicated that Nam Doc Mai was the likely parent.

The tree first fruited in 1960 and the new variety was named after Ralph V. Duncan of Boynton Beach, Florida, who was a flood control district supervisor that had provided maps for a book written by Sturrock.

The variety was recognized for its excellent eating quality and handling characteristics, as well as its production, and later became a nursery stock tree in Florida.

The fruit is oblong in shape and turns yellow when ripe, averaging slightly over a pound in weight.