UNITED STATES DEPARTMENT OF AGRICULTURE
AGRICULTURAL RESEARCH SERVICE
NOTICE OF RELEASE OF
SWEETHEART, tested as ARS 99-88, is a cross of a University of Georgia southern highbush selection (TH 275) with a northern highbush selection (G 567). The cross that produced SWEETHEART was made by M.K. Ehlenfeldt at Chatsworth, New Jersey in 1996, and was selected in 1999 at the MarucciCenter for Blueberry & Cranberry Research and Extension, Chatsworth, NJ.The selection was subsequently evaluated by M.K. Ehlenfeldt between 1999 and 2009.Its desirable characteristics are: superior flavor, very good firmness, good productivity (15.0# for 'Sweetheart' vs. 12.1# for 'Duke', 2005-2009), attractive medium- to medium-large-sized fruit (1.6 g vs. 1.7 g for Duke, avg. 2006-2009), and early, concentrated ripening. The bush of SWEETHEART is vigorous and robust with round fist-like buds similar to 'Ozarkblue'.Flowering time is similar to other northern highbush blueberry cultivars such as 'Bluecrop'. SWEETHEART continues under test, but has not shown any hardiness problems in New Jersey. Midwinter cold hardiness (early January) in 2010 was comparable to 'Bluecrop'. In early February 2007, its LT50 (temperature for 50% damage) was found to be -10? F (LT50 for 'Bluecrop' was -18? F). Although the complete range of adaptation of SWEETHEART has not been established, its background suggests that it may have adaptation in both northern and southern areas. Observations indicate that SWEETHEART will reflower-refruit to a small degree in mild autumns. Provisional precautions: 1) because SWEETHEART has some southern ancestry (~15% V. darrowii), hardiness questions remain for northern areas, 2) because SWEETHEART crops heavily, extra effort is needed to maintain fruit size, 3) SWEETHEART can develop over-ripe flavors if it hangs too long; as an early season cultivar it should be harvested promptly.
This selection is released unconditionally with no warranty given regarding its performance or adaptation under specific environmental or cultural conditions. Nurserymen and researchers may request information on how to obtain propagules by contacting M. K. Ehlenfeldt, USDA-ARS, MarucciCenter for Blueberry & Cranberry Research and Extension, 125A Lake Oswego Road, Chatsworth, NJ, 08019. If requests for propagules exceed the supply, plants will be equitably divided among requesting parties. Genetic material of this release will be deposited in the National Plant Germplasm System where it will be available for research purposes, including the development and commercialization of new cultivars.
Sally Schneider 6-09-2010
Deputy Administrator, Crop Production and Protection Date
Agricultural Research Service, U.S. Department of Agriculture
For more information about Sweetheart please contact: Dr. Mark Ehlenfeldt