以花楸树〔Sorbus pohuashanensis (Hance) Hedl.〕为母本、少叶花楸〔S. hupehensis var. paucijuga (D. K. Zang et P. C. Huang) L. T. Lu〕为父本进行种间杂交，利用筛选出的9对扩增结果稳定且具多态性的EST-SSR引物，对杂交F₁代群体进行杂种鉴定，并对亲本和杂交F1代群体的基因分离规律以及遗传多样性和遗传关系进行分析。结果显示：共获得184株杂交F₁代，其中175株在9个EST-SSR位点上均扩增出双亲条带，说明这些单株为真杂种，杂种率达95.1%；另9株在3~7个位点上呈现异常基因型，即缺失双亲条带或出现新条带。9对EST-SSR引物中，仅sorsd29在亲本中的扩增结果为aa×bb型（纯合互补型），其他8对引物在亲本中的扩增结果为aa×bc型（父本型）、ab×cd型（双亲互补型）或ab×ac型（杂合互补型），因而，在175株真杂种中，仅sorsd29位点未出现基因分离，另8个位点均出现了基因分离，经χ2检验，F₁代分离比与期望分离比均无显著（P>0.05）差异。用9对EST-SSR引物从175株F₁代真杂种中共扩增出28个等位基因，观测等位基因数、有效等位基因数、多态性信息含量、Shannon’s信息指数、观测杂合度和期望杂合度的均值分别为3.1、2.9、0.566、1.076、0.920和0.640。基于Nei’s遗传距离，采用UPGMA法构建系统聚类图，结果显示：在Neis遗传距离0.28处，少叶花楸单独成组Ⅰ，花楸树和175株F₁代单株聚为组Ⅱ；在Nei’s遗传距离0.24处，组Ⅱ可进一步分为2个亚组，其中81株F₁代单株聚为亚组Ⅱ1，另94株F₁代单株与花楸树聚为亚组Ⅱ2。综合分析结果表明：采用EST-SSR分子标记法可对花楸树和少叶花楸的杂交F₁代群体进行有效的杂种鉴定；获得的杂交F₁代单株的基因分离情况符合孟德尔分离定律，且与母本花楸树有较近的遗传关系；总体上看，杂交F₁代群体中175株真杂种的遗传多样性较为丰富。

The interspecific hybridization was conducted by using Sorbus pohuashanensis (Hance) Hedl. as female parent and S. hupehensis var. paucijuga (D. K. Zang et P. C. Huang) L. T. Lu as male parent, the F₁ hybrid population was identified by using nine pairs of EST-SSR primers with stable amplification results and polymorphism, and the gene segregation rule, genetic diversity, and genetic relationship of parents and F₁ hybrid population were analyzed. The results show that 184 F₁ hybrid individuals are obtained, in which the parental bands are all amplified in 175 individuals at nine EST-SSR loci, indicating that these individuals are real hybrids, and the hybrid rate reaches 95.1%; the other nine individuals have abnormal genotypes at 3-7 loci, either missing parental bands or appearing new bands. Among nine pairs of EST-SSR primers, only the amplification result of sorsd29 in parents is aa × bb type (homozygous and complementary type), and the amplification results of the other eight pairs of primers in parents are aa × bc type (male parent type), ab × cd type (parental complementary type), or ab × ac type (heterozygous and complementary type), therefore, among 175 real hybrid individuals, only sorsd29 locus doesn’t show gene segregation, while the other eight loci all show gene segregation, and there is no significant (P>0.05) difference between the segregation ratio of F₁ generation and expected segregation ratio according to χ² test. In total, 28 alleles are amplified from 175 F₁ real hybrid individuals by using nine pairs of EST-SSR primers, and the means of number of observed alleles, number of effective alleles, polymorphism information content, Shannon's information index, observed heterozygosity, and expected heterozygosity are 3.1, 2.9, 0.566, 1.076, 0.920, and 0.640, respectively. The UPGMA method was used to construct systematic clustering diagram based on Nei's genetic distance, and the result shows that at the Nei's genetic distance of 0.28, S. hupehensis var. paucijuga is group Ⅰ individually and S. pohuashanensis and 175 F₁ individuals are clustered into group Ⅱ; at the Nei's genetic distance of 0.24, group Ⅱ can be further divided into two subgroups, in which 81 F₁ individuals are clustered into subgroup Ⅱ1, and the other 94 F₁ individuals and S. pohuashanensis are clustered into subgroup Ⅱ2. The comprehensive analysis result shows that an effective hybrid identification can be conducted for F₁ hybrid population of S. pohuashanensis and S. hupehensis var. paucijuga by using the EST-SSR molecular marker method; the gene segregation situations of F₁ hybrid individuals are all in accord with Mendel's law of segregation, and they have relatively close genetic relationships with the female parent S. pohuashanensis. In general, the 175 real hybrid individuals of F₁ hybrid population have relatively rich genetic diversities.