ARS Investigate Genes Involved in Forming Plum
April 21, 2009
Agricultural Research Service (ARS)
scientists are making progress in determining the genes that control pit
formation in plumsthe first step in a project to develop pitless
varieties of this fruit.
ARS molecular biologists
Callahan and Prunus breeder
Scorza at the ARS
Fruit Research Station in Kearneysville, W.Va., discovered that a set of
genes necessary for production of lignin is rapidly turned on specifically in
pit tissuenot the flesh or skinjust before hardening. Then these
genes quiet down just as quickly after the stone hardens.
Lignin is a material involved in the formation of pits in stone fruit. Fruit
pits consist of the seed and the hard woody material, or stone, surrounding the
The researchers' goal is to establish techniques to stop the genes' activity
and prevent hardening of the pit, thus producing a pitless plum that would be
more appealing to consumers. Pitless fruit would be a premium product that
could provide higher income for growers and could increase consumption of these
The idea of pitless fruits is not new. In the early 1900s, Luther Burbank, a
prolific horticulturalist, crossed a partially stoneless wild plum with
California French prune varieties. These crosses led to commercial-quality
fruit that almost completely lacked the stone, but still contained the seed.
The group used samples of Burbank's crosses for their work.
The research team engineered Burbank's stoneless variety with an
early-flowering trait that will greatly speed up the breeding program. The
resulting fruit has remarkably little stone tissue, but further improvements
are needed to make it edible, according to Dardick. Early flowering will
substantially shorten the time it takes to test the strategies that may lead to
According to Dardick, if successful, the research may be applicable to other
stone fruits, such as cherries, peaches, nectarines and apricots.
more about this research in the April 2009 issue of Agricultural
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture.