Determination of S-genotype in apple and sweet cherry cultivars released at fruit research institute, Čačak

Abstract

Apples and sweet cherries are generally characterized by self-incompatibility, which is controlled by the multiallelic locus S with gametophytic action. Thus the identification of S-genotype represents crucial information for fruit breeders and growers. The aim of this study was to identify the S-genotype of two apple ('Čačanska Pozna' and 'Čadel') and two sweet cherry ('Asenova Rana' and 'Čarna') cultivars developed at Fruit Research Institute, Čačak using the polymerase chain reaction (PCR) method with consensus and allele-specific primers. The S-genotype of apple cultivars 'Čačanska Pozna' (S7S9) and 'Čadel' (S2S7) were consistent with parental combinations 'Starking Delicious' (S9S28) × 'Jonathan' (S7S9) and 'Golden Delicious' (S2S3) × 'Jonathan' (S7S9), respectively. For sweet cherry cultivars 'Asenova Rana' ['Drogans Gelbe' (S1S5) × 'Majova Rana' (S1S4)] and 'Čarna' ['Majova Rana' (S1S4) × 'Bigarreau de Schrecken' (S1S3)], S3S9 and S1S4 were identified respectively, suggesting that the reported pedigree is erroneous. The trueness-to-type of DNA samples of both sweet cherry cultivars was confirmed by comparison of cultivar samples from more than one site. Upon this testing, the remaining inconsistency indicated that aforementioned parentages of the sweet cherry cultivars were incorrect. These discrepancies could be the result of possible pollen contamination, or mistakes either in breeders recording or in seed processing and seedling production. The results of S-genotyping of apple and sweet cherry cultivars provide relevant information on correct assignment of these cultivars to cross-compatibility groups, which are important for cross design in developing new cultivar, as well as for orchard management in the efficient production of fruits.