38个中国大菊品种染色体核型参数的统计分析

为了探讨中国传统大菊（Chrysanthemum×morifolium Ramat.）品种间的遗传差异,选取了38个品种进行核型参数和染色体数目观察和统计。结果表明：多数大菊品种的染色体数目介于50–60之间,为六倍体基础上的非整倍体;其中仅有2个品种染色体数目少于50,3个品种多于60;黄香梨（C.×morifolium‘Huangxiangli’）是唯一染色体数目达到73的品种,推测其为八倍体。观察品种多数为较对称的核型（2A或2B型）;具有随体染色体的品种有30个,占观察品种总数的79%,且古老品种的随体染色体数目较多,千手观音（C.×morifolium‘Qianshouguanyin’）的中期分裂相里最多可观察到6个随体;臂比均值（MAR）部分集中在1.5–2.0之间,臂比方差（VAR）则集中在0.1–0.5之间,臂比均值与臂比方差呈显著正相关,其相关系数（r2）为0.91。各瓣型之间的臂比均值差别不大;古老品种与现代品种在臂比均值和臂比方差上并未表现出明显的差异。三大瓣型（平瓣、匙瓣和管瓣）的核型不对称系数（As.K.C.）差异不显著,其在古老品种中较为一致,而现代品种之间的差异较大。这些数据表明,核型参数对菊花的品种鉴定、分类和遗传分析具有重要参考价值。

Karyotype Analysis of 38 Large-flowered Chrysanthemum Cultivars from China

We surveyed genetic variation among 38 cultivars of Chinese large-flowered Chrysanthemum（Chrysanthemum × morifolium Ramat.） by karyotype parameters and number of chromosomes.The number of chromosomes in most of the cultivars were from 50 to 60 and were hexaploid-based aneuploid.Only 2 cultivars had 50 chromosomes,and 3 had more than 60.C.× morifolium ‘Huangxiangli’ had 73 chromosomes and was considered octoploid.Most cultivars were hexaploid and aneuploid.The karyotypes of all cultivars were 2A or 2B,a type of symmetrical karyotype.Chromo-some satellites were observed in 30 cultivars,79% of these 38 cultivars.As compared with modern cultivars,traditional ones had more satellites.For example,C.× morifolium ‘Qianshouguanyin’ showed 6 satellites in metaphase.The mean of long to short arm ratio（MAR） varied from 1.5 to 2.0,the variation of long to short arm ratio（VAR） varied from 0.1 to 0.5.The mean and the variation of arm ratio were positively correlated,and the correlation coefficient（r2） was 0.91.The mean of arm ratio varied little by corolla shape from traditional to modern cultivars.Asymmetrical karyotypes coefficients（As.K.C.） were similar among the 3 corolla shapes（flat,spoon and quilled） but differed more between modern and traditional cultivars.Therefore,karyotype analysis can provide important information for cultivar identification,classification and genetic study.