12份连翘种质资源的核型参数分析

Karyotype Analysis of Twelve Forsythia Species and Cultivars

采用常规压片法对4个连翘属原种以及6个金钟连翘品种和2个朝鲜连翘品种的核型进行了分析。研究结果发现,除金钟连翘品种Goldrausch为四倍体（2n=4x=56）外,其余11份种质均为二倍体（2n=2x=28）,染色体基数为14。连翘、卵叶连翘、东北连翘、朝鲜连翘的核型分别为2A、3B、2B、3B型,6个金钟连翘品种的核型包括2A、2B、3B 3种,2个朝鲜连翘品种的核型包括2B、3B。12份连翘种质的着丝粒指数差异性不大,介于9.65%~50.00%,染色体类型以中部（m）、近中部（sm）以及近端部（st）染色体为主,未发现端部染色体和随体。结果表明,连翘和东北连翘的亲缘关系最近,与卵叶连翘的亲缘关系最远,金钟连翘品种与东北连翘、朝鲜连翘之间亲缘关系较近。研究结果为连翘属种间、品种间杂交育种和亲缘关系研究提供了细胞学基础。

Karyotypes of twelve Forsythia species and cuhivars were studied using squashing method. The re- suits showed that eleven Forsythia species and cultivars were diploid （2n = 2x = 28 ）, except F. intermedia ＇ Gold- rausch＇ , which was tetraloid （2n = 4x = 56 ）. The karyotypes of F. suspensa, F. ovate, F. mandshurica and F. kore- ana were 2A, 3 B,2B, and 3 B, respectively. The karyotypes of six F. intermedia cultivars included 2A,2B and 3 B. The karyotypes of two F. koreana cultivars included 2B and 3 B. Generally, the centromere index of twelve Forsythia species and cuhivars were not distinctively different, which ranged from 9.65% to 50. 00%. The karyotypes of all the tested Forsythia taxa were mainly made of median region, submedian region and subterminal region, without telo- centric chromosome or satellite. The results from clustering analysis on karyotype parameters of the four Forsythia species showed that F. suspense and F. mandshurica had close genetic relationship, while the genetic relationship be- tween F. suspense and F. ovata was distant. Meanwhile, F. intermedia cuhivars had closer genetic relationship with F. mandshurica and F. koreana, than with F. suspense and F. ovata. The results provided cytological information for genetic relationship analysis and parent selection in interspecific hybridization in Forsythia genus.