First came the seedless grape, then the seedless watermelon, and now a pitless plum is in the works.

Chris Dardick and Ann Callahan, Agricultural Research Service molecular biologists, and stone fruit breeder Ralph Scorza have identified a set of genes that control lignin, which is involved with pit tissue formation.

They are based at the ARS Appalachian Fruit Research Station in Kearneysville, W. Va.

The researchers hope to develop techniques to stop the genes' activity and prevent hardening of the pit. The result would be a pitless plum and eventually pitless stone fruit.

Pitless fruit could provide higher income for growers since consumers would be willing to pay a premium, according to a news release.

The idea of pitless fruit is not new, the researchers say.

In the early 1900s, horticulturalist Luther Burbank crossed a partially stoneless wild plum with California French prune varieties. The crosses led to commercial-quality fruit that almost completely lacked the stone, but still contained the seed.