Marker selection of promising varietal and breeding material of apple tree

Apple tree ( Malus × domestica Borkh.) is a leading agricultural pome crop, one of the main perennial fruit plants in the world, commercially in demand and widespread in the horticultural industry of Russia, including the North Caucasus region. In solving the problem of creating high-quality domestic apple varieties with a long-term type of resistance to the scab (pathogen - Venturia inaequalis (Cooke) G. Winter), the role of prebreeding, including research aimed at accelerated selection using the DNA method, is significant tagging valuable carriers of several Rvi scab resistance genes. The purpose of the study was to study the allelic polymorphism of 15 apple tree scab resistance genes ( Venturia inaequalis (Cooke) G. Winter) in 33 varietal and breeding samples of apple trees to identify sources of long-term resistance to increase efficiency of breeding process. The research was carried out in accordance with programs and methods for the study of apple varieties; Research and Selection Collection of Genetic Resources of Horticultural Crops and the Instrumentation and Analytical Center were used. DNA analysis methods were used in this work. For DNA extraction, a modification of the CTAB method was used, developed at North Caucasian Federal Scientific Center of Horticulture, Viticulture, Winemaking, allowing for better purification of DNA samples from polyphenolic compounds. The work used 22 markers to identify 15 apple scab resistance genes: Rvi1; Rvi2; Rvi3; Rvi4; Rvi5; Rvi6; Rvi8; Rvi9; Rvi11; Rvi12; Rvi13; Rvi14; Rvi15; Rvi16; Rvi17 . Marker selection of new varietal and breeding material made it possible to identify carriers of several genes for apple tree resistance to scab, having in the genome from 2 to 6 different Rvi genes in different combinations. Carriers of 6 resistance genes were identified as the most promising for selection for long-term resistance to scab: Rvi1, Rvi2, Rvi3, Rvi4, Rvi6, Rvi15-1 2/1-21-24; 5 genes: Rvi1, Rvi2, Rvi3, Rvi6, Rvi13 - Karmen; Rvi1, Rvi2, Rvi4, Rvi6, Rvi15 - Mikhsan; 4 genes: Rvi1, Rvi2, Rvi3, Rvi6 - Nadezhnoye; Rvi1, Rvi4, Rvi6, Rvi15 - Gaito Gazdanov; Rvi1, Rvi3, Rvi6, Rvi8-1 2/1-20-56, etc. Identified apple genotypes of domestic breeding, including those created in creative collaboration with colleagues from the Russian Research Institute for Breeding Fruit Crops and Stavropol Experimental Horticulture Station, promising for further breeding and accelerated creation of new high-quality, adaptive varieties with long-term high potential for resistance to the main fungal pathogen of the crop.