Construction of new genomes of columnar apple trees in the Russian research institute of fruit crop breeding

Relevance . The article presents data on the creation of new genotypes of columnar apple trees based on interval crossings of the 2x × 4x type using traditional breeding methods and elements of accelerated assessment of hybrid forms using cytoembryological and molecular genetic methods. Results . Cytological assessment of seedlings obtained from the studied interval crossings of six columnar apple varieties and the selected columnar form 29-35-123 with tetraploid forms 30-47-88 and 25-37-45, which are donors of diploid gametes, showed that seedlings with a triple set of chromosomes prevail and their share is 83.0%. The share of diploids accounts for 17.0%. A comparative assessment of the ploidy of offspring showed that the difference between the yield of triploid seedlings in the offspring of families where different donors of diploid gametes (25-37-45 and 30-47-88) were taken as paternal forms is insignificant. From the tetraploid 30-47-88, 81.7% of triploid offspring were obtained, from 25-37-45 — 91.3%. The data of molecular genetic analysis confirm that in combinations where both parents have the scab immunity gene, the yield of immune seedlings is high (70,7%) and corresponds to the splitting on this basis in a ratio of 3:1. n families where only one of the parents carries the Rvi6 gene in its genotype (Garland × 25-37-45, 29-35-123 × 25-37-45, Moscow necklace × 30-47-88 and Constellation × 25-37-45) immune seedlings were less common (52%). A unique combination of columnarity, the Rvi6 gene and a triple set of chromosomes in one genotype is characteristic of 23.1% of seedlings.