Evaluation of Md-ACS1 gene polymorphism in apple trees for isolation of the identified composition of gene pool and breeding for long-storage fruits

The apple tree (Malus × domestica Borkh.) is the most important perennial fruit crop widely cultivated and used in agricultural production around the world. The problem of extending shelf life and sale of fresh fruit crops is of great importance due to the year-round active use and demand among the population. To create commercially attractive, popular and valuable apple varieties of Russian breeding with genetically determined long-term keeping quality of fruits, the role of pre-breeding based on the study and mobilization of available biological resources including the use of DNA marking to identify the most valuable genotypes for the desired priority trait, is significant. The purpose of the study was to study allelic polymorphism of Md-A CS1 gene in 37 apple accessions to identify sources of long-term storage of fruits for further breeding use. The research was carried out in the Center for Collective Use ‘Research and Breeding Collection of Genetic Resources of Horticultural Crops’ using generally accepted programs and methods for variety study and selection of apple trees. The methods of DNA analysis were applied in the work. For DNA extraction, the CTAB method modified at North Caucasian Federal Scientific Center of Horticulture was used. According to DNA marking data, carriers of homozygous allelic combination (Md-ACS1–2/2) were identified among the studied apple accessions of Russian breeding: Persikovoe, Georgiy, Azimut, hybrid 17/1–6–47 (Champion × Modi), and foreign varieties: Smeralda, Fuji Mimo. The selected varieties and forms are promising in creating Russian genetic resources with improved commercial fruit traits including genetically determined increase in length of storage period. They can be used in breeding using DNA-marker selection for several target genes of quality, keeping quality and density of fruit pulp.