Genetic mapping and selection of table grape fruit quality characteristics in a segregating population and evaluation of marker transferability

Abstract Grape production and fruit quality traits such as cluster size, berry shape, and timing of fruit development are key aspects in selecting cultivars for commercial production. Molecular markers for some, but not all, of these traits have been identified using bi-parental or association mapping populations. Previously identified markers were tested for transferability using a test panel of commercially available grape cultivars. Markers had little to no ability to differentiate grape phenotypes based on the expected characteristics, except the marker for seedlessness. Using a biparental inter-specific cross, forty-three QTL, both previously identified and new genomic regions, associated with berry shape, number, size, cluster weight, length, and time to flower, veraison and full color were detected. KASP markers designed on newly identified QTL were tested for transferability using the same panel. Transferability was low when use types were combined, but varied when use type were evaluated separately. Comparison of a 4Mb region at the end of chromosome 18 revealed structural differences among grape species and use types. Table grape cultivars had the highest similarity in structure for this region (> 75%) compared to other grape species and commodity types.