Dear Editor,Petunia possesses self-incompatibility (Sl),by which pistils reject self-pollen but accept non-self pollen for fertilization (de Nettancourt,2001;Iwano and Takayama,2012).Genes that regulate self-/non-self-recognition between pollen and pistil are located at the highly polymorphic S-locus.An S-haplotype contains the pistil-specific S-RNase gene that regulates pistil specificity (Lee et al.,1994).The first S-locus F-box (SLF) gene was identified in Antirrhinum hispanicum by Lai et al.(2002),and subsequently Sijacic et al.(2004) showed that an SLFgene in Petunia inflata is involved in pollen specificity.Recently,Kubo et al.(2010) found that multiple,but an as-yet unknown number of,SLF genes collectively regulate pollen specificity.