Submitted to: Germplasm Release
Publication Type: Germplasm Release
Publication Acceptance Date: October 9, 2009
Publication Date: October 9, 2009
Citation: Scorza, R. 2009. Orablue plum. Germplasm Release. Docket 0003.10. Technical Abstract: The Agricultural Research Service, U.S. Department of Agriculture, announces the release of Orablue plum. The purpose of this release is to provide a high quality notably large late-midseason plum for the mid-Atlantic and other Prunus domestica plum growing areas of the U.S. Orablue, tested as B7054, was selected in 1970 by Harold W. Fogle at the USDA-ARS, Agricultural Research Center, Beltsville, Maryland. The parentage is NY981 open pollinated. NY981 was a selection from the New York Agricultural Experiment Station, Geneva, New York. The parentage of this selection is not known. Orablue was initially tested in Beltsville, Maryland. It has been extensively tested in West Virginia with limited testing in Geneva, New York, and Byron, Georgia. Orablue (Prunus domestica L.) ripens at approximately the same time as Stanley plum, generally in mid to late September in Kearneysville, West Virginia. Depending on crop load and environment, Orablue fruit range in length from 60 to 67 mm, from 43 to 57 mm in width, and weigh 72 to 122 grams. Sugar content measured as degrees brix ranges from 15% to 22%. The flesh is amber in color, firm and juicy, with a pleasing sugar-acid balance and excellent flavor. The skin is deep purple with a wax bloom. The stone is semi-free from the flesh. In a small number of fruit (approximately 8%), the stylar (pointed) end of the seed separates and remains in the flesh. Orablue trees have a semi-erect growth habit and produce fruiting spurs. Orablue trees bloom several days to one week ahead of Stanley plum depending on Spring temperatures or at about the same time as Reine Claude and Bluebyrd plums. Fruits ripen in mid to late September and into the first week of October in Kearneysville, West Virginia. Orablue is a self-incompatible cultivar and requires a pollinator for fruit set. In a mixed planting with a mixture of other plum varieties, Orablue has been shown to set a good crop of fruit. Controlled crosses have produced Orablue fruit set using Green Gage and President plums as pollinators. Trees of Orablue survive and crop well in Kearneysville, West Virginia. Orablue is not adapted in the Southern U.S. and has been shown to be susceptible to plum leaf scald (Xylella fastidiosa) and plum leaf spot (Coccomyces prunophorae) in Byron, Georgia. It is also susceptible to black knot disease (Dibotryon morbosum). The Agricultural Research Service has no trees of Orablue for distribution. A limited amount of heat-treated budwood of Orablue is available from NRSP-5, Washington State University, Prosser, Washington 99350. Genetic material of this release will be deposited in the National Plant Germplasm System, where it will be available for research purposes, including development and commercialization of new varieties/cultivars.