Harnessing the power of RosBREED: Development, validation, and application of DNA tests for predicting peach flavor and other valuable rosaceous tree fruit traits

DNA tests that predict valuable trait levels are essential for widespread adoption of marker-assisted breeding (MAB) of rosaceous tree fruits. The RosBREED project has facilitated development of DNA tests for important traits in peach, apple, and cherry, including peach sweetness and acidity. Based on a quantitative trait locus (QTL), discovered on peach chromosome 7 by RosBREED collaborators, explaining ~20% of phenotypic variation for titratable acidity in normal acid peaches and ~10% of variation in soluble solids content, a DNA test (“G7Flav-SSR”) was developed at Washington State University. Standard cultivars and University of Arkansas (UA) and Clemson University (CU) breeding germplasm were used to confirm predictiveness of the DNA test, where G7Flav-SSR clearly differentiated low:low, low:high, and high:high allelic combinations. Validation of this new DNA test was conducted on unselected families of CU and AR germplasm. G7Flav-SSR results were used to guide 2014 crossing decisions in the UA peach breeding program. This advance in DNA-informed breeding represents an example of successful collaboration among institutions and across disciplines. Other DNA tests emerging from RosBREED include those for the prediction of peach maturity time, bacterial spot resistance, firmness, and blush, apple sweetness, acidity, and firmness, and sweet cherry maturity time and firmness. By harnessing the power of collaboration, specifically the integration of pedigree, phenotypic, and genotypic data generated by RosBREED team members for QTL discovery, the development of these DNA tests was possible. Tools such as G7Flav-SSR are now available to make DNA-based predictions a routine part of tree fruit breeding.