The domesticated apple (Malus x domestica Borkh.) is a major fruit crop of temperate regions of the world. ‘Fuji’ apple (Ralls Genet x Delicious), a famous apple cultivar in Korea, has been very popular since its promotion in Japan in 1958. ‘Fuji’ and its bud mutant cultivars possess variable levels of genetic diversity. Nonetheless, the phenotypes of each group, which are classified into the bud mutation groups: early season, fruiting spur, and coloring, are similar.
DNA markers are useful tools that play an important role in plant cultivar identification. They are usually based on polymerase chain reaction (PCR) and include simple sequence repeats (SSRs), inter-simple sequence repeats, and random amplified polymorphic DNA. However, DNA markers were not used effectively in the complete identification of plant cultivars because of the lack of known DNA fingerprints. Recently, a novel approach called the cultivar identification diagram (CID) strategy was developed to facilitate the use of DNA markers for separate plant individuals.
Pre-selection for fruit skin color at the seedling stage would be highly advantageous, with marker-assisted selection offering a potential method for apple pre-selection. A and MdMYB1 alleles are allele-specific DNA markers that are potentially associated with apple skin color, and co-segregate with the Rf and Rni loci, respectively. Here, we assessed the potential application of these 2 alleles for marker-assisted breeding across 30 diverse cultivars and 2 apple seedling progenies.