S-locus genotyping on stone fruits in Hungary: a review of the most recent achievements

Central Europe can be taken as a geographical and historical connection zone between the western growing countries and Asiangene centres of Prunus tree fruits. The determination of the S-genotype of stone fruit (mainly almond, plum, cherries and apricot) cultivarsand landraces has both practical and theoretical significance. Our group has allocated complete S-genotypes for more than 200 cultivars andselections of almond, Japanese plum, sweet cherry and apricot. Among Eastern European almond cultivars, two novel cross-incompatibilitygroups (CIGs) were identified. S-alleles of a related species were also shown in P. dulcis accessions; a fact seems to be indicative of introgressivehybridization. Our results with Japanese plum clarified and harmonized two different allele nomenclatures and formed a basis for intensiveinternational studies. In apricot, a total of 13 new S-alleles were identified from Eastern European and Asian accessions. Many Turkish andNorth African cultivars were classified into new CIGs, III–XVII. Results suggest that the mutation rendering apricot self-compatible mighthave occurred somewhere in south-east of Turkey and we were successful to confirm the presumed Irano-Caucasian origin of North Africanapricots based on the geographical distribution of S-alleles. In sweet cherry, new alleles have been identified and characterized from Turkishcultivars and selections. In addition, wild sweet cherry and sour cherry S-alleles were also shown indicating a a broader gene pool in Turkeyas compared with international cultivars. We also used S-genotype information of Ukrainian sweet cherry cultivars to design crosses in afunctional breeding program. Our results exhibit an increased number of S-alleles in tree fruit accessions native to the regions from EasternEurope to Central Asia, which can be used to develop S-genotyping methods, to assist cultivation and draw inferences for crop evolution