Self-incompatibility (S) genotypes of cultivated sweet cherries – An overview update 2020

The fertility in sweet cherry is determined by a gametophytic self-incompatibility system, controlled by a multi-allelic S locus who prevents self-pollination. The fertilization is controlled by the interaction of an S allele specific ribonuclease (S-RNase) in the style with a pollen S specific F-box protein gene (SFB). Knowledge about the S genotype of sweet cherries is very important for cherry growers and breeders. In the last years molecular markers have been developed to distinguish the S alleles in sweet cherries. In the new update from October 2020 a total of 63 incompatibility groups in 1483 sweet cherries have been defined. 26 sweet cherries have a unique combination of S alleles and were described as universal donors and placed in the incompatibility group 0. Additionally, there exist 91 self-compatible sweet cherries, called group SC. A total of 22 different S alleles are 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. The goal of this work is to summaries all known data of the S alleles in cultivated sweet cherries. In Table 1 the S genotypes of all studied sweet cherries are described. Furthermore it includes information about the parentage if they are known. Table 2 gives an overview about all the detected incompatibility groups. The groups are sorted according to the group numbers and the S allele numbers, respectively. In Table 3 all genotypes of the incompatibility group 0 with a unique S genotype are listed. Table 4 includes all known self-compatible sweet cherries. All references to the information of the S genotypes are listed in a file named 'References'. The present update needs to be further improved with all new S alleles data of sweet cherries. In addition, all new information about the parentage is very important for the breeding research. Please send all new or corrected data to the S alleles and the parentage of sweet cherries to mirko.schuster@julius-kuehn.de. An update of the S allele overview will take place in the next years.