The 2012 ASHS Annual Conference

Discoveries in genomics provide new, useful information on genetic control of important traits in apple (Malus domestica Borkh.). Converting these discoveries into genetic tools would enhance efficiency of apple breeding via marker-assisted selection compared to conventional phenotype-based approaches. Developing new cultivars that produce delicious fruit in abundance is the major goal of apple breeding programs. Meeting or exceeding consumer expectations requires this fruit deliver a consistently fresh sensation, even after long term storage. We define apple fresh sensation as a combination of crispness, acidity, and juiciness. A location in the apple genome associated with these traits, the malic acid, or Ma locus, was reported a decade ago. We have identified Ma variants that appear to predispose certain cultivars to more consistently produce apples with a fresh sensation: high crispness, acidity, and juiciness. As part of the USDA–NIFA funded the RosBREED project, we are developing, validating, and implementing predictive genetic tests that can identify useful variants through pedigree-based analysis and thereby predict genetic potential for many fruit quality traits, including fresh sensation. Screening over 1000 apple cultivars, breeding selections and seedlings for two simple sequence repeat markers flanking the Ma locus revealed numerous variants associated with fresh sensation differences. High-resolution SNP marker data from the RosBREED project is identifying other regions in the apple genome associated with fresh sensation and identifying and characterizing functional variants for application in apple breeding programs.