关键词: 梨, 叶绿体DNA, 单倍型, 遗传多样性

Abstract: Eight chloroplast DNA（cpDNA）primers were selected from 32 universal primer pairs to
assess the genetic diversity of 37 pear accessions in Liaoning Province. Among these primer amplification products，four cpDNA fragments possessed variation sites. Nine singleton variable sites，three parsimony
informative sites and two INDELS were obtained from the combined cpDNA fragments（3 688 bp）. Two
trnL-trnF-487 haplotypes，four trnL-trnF-413 haplotypes，two rbcL haplotypes and three trnS-psbC
haplotypes were identified among the 37 pear accessions，respectively，and four haplotypes were identified
based on the combined fragments. Non-coding region trnL-trnF-413 exhibited highest polymorphism with
the most number of haplotypes，the most abundant haplotype（gene）diversity and nucleotide diversity，
the most variant of haplotype diversity and the highest standard deviation of haplotype diversity. Values of
haplotype（gene）diversity（Hd）and nucleotide diversity（Pi）of 37 pear accessions in Liaoning Province
are 0.577 and 0.00055，respectively. Tajima’s test showed all Tajima’s D values are not statistical
significant except for the rbcL fragment in P < 0.05，indicating that natural selection has an effect on
mutations of this fragment. Both P. ussuriensis and P. bretschneideri accessions contained haplotypes
HAP_1，HAP_2 and HAP_3，showing a close relationship between them；While HAP_5 is shared by P.
communis accessions independently. The network constructed with Median-Joining network calculation
exhibited that HAP_1 has a far relationship with HAP_2 and HAP_3，whereas HAP_5 has a far
relationship with those three haplotypes mentioned above.

Key words: Pyrus, chloroplast DNA, haplotype, genetic diversity