关键词: 楸子, 叶绿体DNA, 单倍型, 遗传多样性

Abstract: Four intergenic region，trnH-psbA，trnS-trnG spacer + intron，trnT-5′trnL and 5′trnL-trnF of 49 accessions of newly collected germplasms of Malus prunifolia（Willd.）Borkh. were amplified by four primers. Based on genetic variation of 4 chloroplast intergenic regions，the genetic diversity of Malus prunifolia among different populations were explored from the perspective of maternal inheritance. The results showed that the length of four intergenic regions of chloroplast DNA was 3 790 bp after sequencing，splicing，alignment and merging，and 173 variable sites were detected including 2 singleton variable sites，20 parsimony informative sites and 151 insertion/deletion gaps. Among the 49 accessions of Malus prunifolia，the number of variable sites of region trnH-psbA，trnS-trnG spacer + intron，trnT-5′trnL and 5′trnL-trnF were 26，25，120 and 2. The number of haplotypes for four regions being were 9，7，8 and 3. After four regions being merged the haplotypes of chloroplast DNA fragments were 14. The region with the highest nucleotide and haplotype diversity was trnH-psbA（Hd = 0.775，Pi = 0.02143），and the nucleotide andhaplotype diversity of 5′trnL-trnF was the lowest（Hd = 0.481，Pi = 0.00072）. The cpDNA diversity of Malus prunifolia with four chloroplast DNA regionsmerged was high（Hd = 0.854，Pi = 0.00949）. Tajima’s test showed all Tajima’s D values were not significant at P > 0.10，which indicated that variation of those chloroplast regions followed neutral theory of molecular evolution. The genetic variation of Malus prunifolia mainly existed within populations. Gene exchange among different populations is frequent，and genetic differentiation among most of populations is less，which has little relationship with geographical distance.

Key words: Malus prunifolia, chloroplast DNA, haplotype, genetic diversity