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' (S2 S9) and 'Kizashi' (S2 S3), 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 S2 S9; no mutation occurred within either of the S-genes. The reciprocal crosses between 'Megumi' and 'Hatsuaki' (S3 S9) resulted in fruits with seeds, whereas those between 'Megumi' and 'Redgold' (S2 S9) or 'Megumi' and 'Kinsei' (S2 S9) resulted in no seeds. These results indicate that the self-compatibility of 'Megumi' is not attributable to defects within the S-genes.