6个香雪兰品种的染色体核型及聚类分析

以香雪兰（Freesia hybrida）6个品种的根尖为研究材料进行核型分析以揭示其核型特征，进一步通过聚类分析品种间的相似性并探讨可能的亲缘关系。结果表明：香雪兰6个品种均为四倍体，染色体数目都为44。6个品种的核型公式不同：‘Gold River’为2n=4x=44=33m+11sm，‘White River’为2n=4x=44=1M+34m+9sm，‘Castor’为2n=4x=44=35m+9sm，‘上农红台阁’为2n=4x=44=32m+12sm，‘Pink Passion’为2n=4x=44=38m+6sm，‘Red River’为2n=4x=44=37m+7sm。核型参数因品种而异，其中，‘Castor’在相对长度范围和臂比范围上均为最广，‘上农红台阁’核不对称系数最大。6个品种核型不对称系数为57.00%~60.07%，核型类型均为2B，进化程度中等，处于由对称至不对称的过渡阶段，其核型进化的趋势大致为：‘Pink Passion’→‘Red River’→‘Gold River’→‘White River’→‘Castor’→‘上农红台阁’。聚类结果显示，遗传距离为15时可将所有品种分为两类，第一类包含‘Gold River’‘上农红台阁’和‘Castor’； 第二类包含‘Pink Passion’‘Red River’和‘White River’，其核型参数的差异可作为香雪兰品种分类和鉴定的辅助依据，为其细胞学研究和育种实践提供理论参考。

Karyotype and Cluster Analysis of Six Freesia hybrida Cultivars

The root tip of six cultivars of Freesia hybrida was used as the plant material for karyotype analysis to reveal their karyotype characteristics. Then cluster analysis was performed to clarify the similarity among the six cultivars and to explore their relationship. The results showed that the six freesia cultivars were all tetraploid with 44 chromosomes. The karyotype formula of six cultivars of F. hybrida were as follows respectively： 2n=4x=44=33m+11sm for ‘Gold River’， 2n=4x=44=1M+34m+9sm for ‘White River’， 2n=4x=44=35m+9sm for ‘Castor’， 2n=4x=44=32m+12sm for ‘SN Hongtaige’， 2n=4x=44=38m+6sm for ‘Pink Passion’ ， and 2n=4x=44=37m+7sm for ‘Red River’. The karyotype asymmetry coefficient ranged from 57.00% to 60.07%. The karyotype types were all 2B， and the degree of evolution was medium，which was in the transition stage from symmetry to asymmetric. The evolution trend of karyotype was： ‘Pink Passion’→’Red River’→‘Gold River’→‘White River’→‘Castor’→‘SN Hongtaige’. The clustering results showed that when the genetic distance was 15， it could be divided into two categories： the first category included ‘Gold River’， ‘SN Hongtaige’ and ‘Castor’， the second category included ‘Pink Passion’， ‘Red River’ and ‘White River’. The difference of its karyotype parameters could be used as the basis for the classification of different cultivars of freesia plants， provided theoretical reference for its cytological inheritance and breeding practice in future.