S-genotypes of 15 Apple Cultivars and Self-compatibility of 'Megumi'

Abstract

S-genotypes of 13 apple (Malus x domestica Borkh.) cultivars and 10 progenies of 'Megumi' were identified by S-allele-specific PCR-RFLP analysis. The S-genotypes of 'Gala' and 'Fuji' were reconfirmed by the analysis. The S-genotypes of 'Kinsei' (S₂S₉) and 'Kizashi' (S₂S₃), were inconsistent with expected S-genotypes of their parents, indicating that they are derivatives from some other pollen parents having S₉- or S₃-allele. 'Tsugaru', 'Akagi', and 'Youkou' seem to have been produced by using pollen parents possessing S₇-, S₇- or S₉-allele, respectively. The S-genotype of self-compatible 'Megumi' was identified as S₂S₉ ; no mutation occurred within either of the S-genes. The reciprocal crosses between 'Megumi' and 'Hatsuaki' (S₃S₉) resulted in fruits with seeds, whereas those between 'Megumi' and 'Redgold' (S₂S₉) or 'Megumi' and 'Kinsei' (S₂S₉) resulted in no seeds. These results indicate that the self-compatibility of 'Megumi' is not attributable to defects within the S-genes.