Self-incompatibility (S) genotypes of cultivated sweet cherries – An overview 2023-Update

A gametophytic self-incompatibility (GSI) system determines fertility in sweet cherries and prevents pollination with own and genetically related pollen. This mechanism is controlled by a multi-allelic S locus coding for two genes involved in fertilization: the S allele-specific ribonuclease (S RNase) expressed in the female style and the S specific F-box protein (SFB) in the male pollen. Knowledge about the S genotype of sweet cherries is very important for cherry growers and breeders. Molecular markers have been developed to distinguish the S alleles in sweet cherries. In this new update from February 2023, a total of 72 incompatibility groups in 1700 sweet cherry cultivars have been listed. Twenty-six sweet cherry cultivars have a unique combination of S alleles, were described as universal donors and were categorized in the incompatibility group 0. Additionally, there exist 91 self-compatible (SC) sweet cherry genotypes belonging to the group SC. A total of 26 different S alleles were described in the cultivated sweet cherries up to date. These are the S alleles S1, S2, S3, S4, S5, S6, S7, S9, S10, S12, S13, S14, S16, S17, S18, S19, S21, S22, S24, S27, S30, S37 and S38 (S7m), and the three mutated, non-functional S alleles S3', S4', S5'. This work summarizes all available data on S allele genotyping for in cultivated sweet cherries. Table 1 describes the S genotypes of all sweet cherries studied. It also contains information about the parentage, if known. Table 2 gives an overview about of all the defined incompatibility groups. The groups are sorted according to their group numbers or the S allele numbers, respectively. Table 3 lists all genotypes of the incompatibility group 0, which exhibit a unique S genotype. Table 4 includes all known self-compatible sweet cherry genotypes of the group SC. All published data used to describe of the S genotypes are listed in the file named 'References'. For S genotyping of sweet cherries, we have established a reference assortment including sweet cherry accessions for a large scale of S alleles (Table 5). These reference genotypes were planted in the orchard of the Julius Kühn-Institut in Dresden-Pillnitz.The present dataset will be regularly updated and improved with all new S alleles data of sweet cherries. In addition, all new information about the parentage is very important for breeding research. Please send all news or corrections regarding the S allele genotype and parentage of sweet cherries to [email protected] or [email protected]. An update of the S allele overview will be provide in the coming years.