ASHS 2025 Conference

Prior to the formal breeding programsof the 19th century, farmers contributed to apple (Malus× domestica Borkh.) breeding by selecting trees based on the desirable characteristics. The transcontinental seed spread was common, and modern breeding programs identified elite commercial trees and high quality fruits. There is a rekindling interest in low-chill apples, both as a high value crop in the USA Southeast, as well as development of new varieties to confront climate change. But the genetic record is poor. Dorsett Golden (DG) is low chill apple cultivar believed to have been discovered in The Bahamas by a Mrs. Dorsett in 1950. As legend has it, she was a jet-setting traveler that loved apples, and planted a set of trees when she relocated to the Bahamas. This allegedly led to the identification of ‘Dorsett Golden’. While this quickly became the accepted story, some questioned the claim. Observations of phenological data in DG trees next to other Israeli germplasm (e.g. ‘Anna’, ‘Ein Shemer’) led Dr. Wayne Sherman to posit in 1980 that DG’s origin was likely from the Israeli breeding program. To test this hypothesis, whole genome sequence from DG was compared to ‘Anna’ and other reference sequences in public databases. Consistent with Dr. Sherman’s 45 year old predictions, DG shares it’s most significant sequence similarity to ‘Anna’, and less with other low-chill varieties. The majority (~92%) of the total variants are in intergenic, upstream, downstream, or intronic regions suggesting recent divergence of ‘Anna’ and DG. The results are consistent with Dr. Sherman’s phenological data that suggest that DG possessed genetics more similar to Israeli genotypes than a chance seedling from Golden Delicious as legend describes. Most importantly, the study illustrates the power of genomic sequencing in selection of parents for low-chill apple crosses as well as debunking horticulutral methology.