Peach (Prunus persica) as a species is self-compatible (SC), although most other Prunus fruit tree species are partially or fully self-incompatible. We previously identified 3 mutated S haplotypes, S¹, S², and S^2m, that confer self-compatibility on commercial peach cultivars for fruit production. In this report, we identified 2 novel SC S haplotypes, S³ and S⁴, among 130 peach cultivars and strains consisting mainly of ornamental cultivars and wild strains. The S³ haplotype was found only in ornamental cultivars, while the S⁴ haplotype was found mainly in wild strains. S-RNases in the S³ and S⁴ haplotypes appeared to have no defects in their primary structures. S haplotype-specific F-box (SFB) sequences were also present in the S locus downstream of the S³- and S⁴-RNases. These SFB sequences were in a reverse transcriptional orientation as has been reported in most other functional Prunus S haplotypes; however, both SFB³ and SFB⁴ appeared to be mutated. DNA sequencing of the entire downstream region of SFB³, extending about 12 kbp to the stop codon of S-RNase, revealed the presence of a premature stop codon 975 bp downstream from the SFB³ start codon. No sequence homologous to SFB downstream of the stop codon was found. There was a 4946 bp insertion in the middle of SFB⁴. The original SFB⁴ sequence, obtained by removing the inserted sequence, encodes a typical SFB. Based on the 3 previously identified peach S haplotypes, we supposed that the S³ and S⁴ haplotypes were also SC pollen part mutant (PPM) S haplotypes. Here, we also discuss possible reasons for all peach S haplotypes identified so far having the PPM SC S haplotype.