Abstract: Partial S-RNase genes of pear were amplified and cloned by using a pair of primers ( P1 and P2) based on the conserved regions C1 and C3 of pear S-RNase structure in six cultivars of unknown S-geontypes. The PCR products were sequenced and compared in GenBank. The S-genotypes of the six tested self-incompatible cultivars were identified as follows: ‘Kuerle Xiangli’ ( Pyrus bretschneideri Rehd. ) was S₂₁ S₂₈ ,‘Pingguoli’ ( P. bretschneideri Rehd. ) was S₁₇S₁₉ , ‘TaiwanMili’ ( P. pyrifolia Nakai) was S₁₁ S₂₂ , ‘Hululi’ ( P. comm unis L. ) was S_a S_b , ‘J ingbai’ ( P. ussriensis Max. ) was S₁₆ S₃₀ , ‘Zaoli 18’ ( P. ussriensis Max. ) was S₄ S₂₈. S₂₈-RNase and S30-RNase were deposited in GenBank under the accession numbers of AY562394 and AY876945.

Key words: Pyrus, Self-incompatibility, S-RNase gene, S-genotyping