Molecular methods in apple breeding for resistance to rosy leaf-curling aphid

The rosy leaf-curling aphid ( Dysaphis devecta Walk) is a widespread pest insect on apple-trees ( Malus × domestica Borkh.). The aphid damages both young trees and old trees. The aphid forms the colonies on the rind, leaves and shoots and it is nourished by apple tree juice. Some cultivars exhibit resistance to this insect owing to appropriate genes in genome. The current methods permit to identify the genes of such resistance and to transfer of them purposefully to created varieties. In presented article the molecular marker technology was used for detecting resistance Sd -locus to rosy leaf-curling aphid, basing on PCR with SdSSR-F/SdSSR-R primers. The Discovery и Fiesta cultivars were used as a control, the first one as a parent to create the plant mapping populations, and the second one as a carrier of Sd1 gene and the corresponding marker. The allele linked with Sd -locus has a size of 183 bp. The collection of 132 apple cultivars and hybrids was tested for Sd -locus, and the Sd -locus identified in genomes of 31 apple accessions from different countries. Sd -locus is presented in ancient cultivars, known as long ago as ХIХ century (Belyi Naliv, Papirovka, Pepin Litovskii, Chulanovka, Cox's Orange Pippin) and cultivars of modern breeding (Sinap Belorusskii, Belorusskoe Malinovoe, Slava Pobeditelyam, Charavnitsa). The molecular marker technology was applied for developing promising apple hybrid seedling resistant to rosy leaf-curling aphid.