The use of the isoenzymic marker gene Got-1 in the recognition of incompatibility S alleles in apple

The S incompatibility system of apple was confirmed through the application of the gene Got-1 for glutamate oxaloacetate transaminase as a marker for the S locus. The 11S alleles proposed by Kobel et al. (1939) were confirmed through anomalous segregations for Got-1 observed in 14 semi-compatible crosses and regular segregations observed in 2 fully compatible crosses. The S allele genotypes of Idared (S ₃ S ₇), Cox (S ₅ S ₉) and Fiesta (S ₃ S ₅) were determined and found to fall within the original series. By associating parental incompatibility genotypes with the segregation of Got-1 alleles, we were able to deduce the coupling of S and Got-1 alleles in 9 varieties.