Identification of new complex sources of resistance to apple diseases using molecular methods in Belarus

In order to identify new complex sources of resistance to apple diseases, a hybrid fund, created in 1994-2007 – 22 364 plants of one year, obtained from 252 crossing combinations and selections in the breeding plot – 4936 plants was analyzed. 120 selections were evaluated in the primary test orchards on rootstocks 62-396 and PB-4, of which 12 promising hybrids were identified. DNA preparations were extracted from fresh apple-tree leaves using the Genomic DNA Purification Kit (Thermo scientific, EC) kit. Markers: OPL19, AD13-SCAR, OPB12 STS, VfC1 and VfC2, AL07-SCAR and AM19-SCAR, Vf2ARD, were used to identify the scab resistance genes Rvi2, Rvi4, Rvi5, Rvi6, Rvi17 and for identification of powdery mildew resistance genes Pl1, Pl2, Pl-w, Pl-d are the markers OPU02 SCAR, OPAT20450, EM M02, EM DM01. The presence of the dominant allele of the Rvi6 gene in the homozygous state (VfVf) was established in three hybrids: 94-13/39, 99-39/76 and 2007-18/19, in the heterozygous (Vfvf) – in six hybrids and cv. Diyament. Comparison of the results of DNA analysis and experimental field data of resistance to scab and powdery mildew allowed to obtain reliable results on the presence of resistance genes in the 12 apple genomes studied, obtained as a result of targeted hybridization of the original forms – derivatives of various apple species. New sources with complex resistance to scab and powdery mildew – carriers of several resistance genes in one genotype have been identified: 2000-45/70 (Rvi2, Rvi4, Rvi5, Rvi6 Pl-d), 94-13/39 (Rvi2, Rvi5, Rvi6), 2007-19/15 (Rvi2, Rvi6 Rvi17, Pl-d).

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