Determination of Plum pox virus resistance and self-incompatibility using molecular markers in the local apricot (Prunus armeniaca) populations in Turkey

The self (in) compatibility (SI/SC) and Plum pox virus (PPV) resistance loci of 256 naturally grown seed-borne apricot trees were investigated by molecular markers. The aim of the study was to observe allele frequency differences at the both loci across apricots of the eastern, middle, and European part (Thrace) of Turkey. In the Thrace region, the Central Anatolia and the Eastern Anatolia, 12, 14 and 12 S alleles were identified, respectively. The frequency of unidentified alleles was 3, 3 and 1% in the first, second and third group, respectively. The findings show that the allele SC and its derivative S8 allele is common (49%) in the Thrace region but poor in the other two regions (11% in the east and 16% in the middle). This suggests the possibility that the most western part of Turkey could be emergence region of SC allele. PPVres locus, identified in the upper arm of the linkage group (LG1), is the major PPV resistance locus accounting for 70% of the Stark Early Orange/Harlayne type PPV resistance. Four markers (PGS1.21, PGS1.23, PGS1.24, and ZP002) linked to PPVres locus were used to the screen the 256 samples in this study and none of the samples depicted PPVres linked allelic variant of these four loci showing that Turkey is not a PPV resistance source