地被菊匍匐性的遗传分析与RAPD标记研究

Genetic Analysis and RAPD Marker of Creeping Habits in Ground-Cover Chrysanthemum

【目的】探讨地被菊株型匍匐性的遗传控制,并寻找与匍匐性连锁的RAPD标记,为匍匐型地被菊新品种选育、分子标记辅助育种和匍匐性相关基因的克隆奠定基础。【方法】以盆栽小菊品种‘早意大利红’为母本,地被菊品种‘03(6)-12’为父本构建F1群体,从F1中选取株型表现为匍匐、直立和中间型的单株各1株,分别自交,构建F2群体,并以选取的3个类型F1单株为母本与‘03(6)-12’回交,构建BC1群体。以主枝分枝角度作为株型划分依据,统计每个群体中不同株型分离比,推测地被菊株型控制相关基因特点。此外,以F1分离群体为试材,采用集团分离分析法(bulkedsegregantanalysis,BSA)构建株型匍匐/直立基因池,利用200个RAPD随机引物筛选与地被菊匍匐基因相连锁的分子标记。【结果】通过遗传分析和χ2检验表明,地被菊匍匐/直立特性由1对不完全显性主效基因控制,同时存在微效修饰基因。筛选出1个与地被菊匍匐性状控制基因相连锁的分子标记A-10555。经过重复性验证和群体单株验证,该标记与地被菊株型匍匐/直立位点遗传距离为7.96cM。【结论】以主枝分枝角度作为株型的划分标准是可行的,通过F1、F2和BC1分离群体能对地被菊株型控制位点进行有效分析。获得的分子标记与株型匍匐/直立位点的遗传距离小,能用于辅助育种。

[Objective] In order to provide bases for molecular assisted breeding, and for cloning creeping habit related genes from the ground-cover chrysanthemum, the inheritance traits of creeping habit were studied, and the RAPD markers related to this habit were screened. [Method] F1 population was derived from interspecific cross between ‘Zaoyidalihong＇ （female parent） and ground-cover chrysanthemum ‘03（6）-12＇ （male parent）. The plant type was divided into creeping, erect and intermediate （non-creeping and non-erect） types according to the branching angle of main branches. Individuals of each plant type in FI were randomly selected, and self-cross was made to generate the F2 population. BC1 population was obtained from back cross of the selected individuals with ‘03（6）-12＇. The segregation ratio of different plant types was documented in seven populations. The gene bulk of creeping and erect plant type in F1 population was constructed by using bulked segregant analysis （BSA） method. 200 RAPD arbitrary primers were used to screen creeping habit related molecular markers. [Result] Genetic analysis and chi-square test showed that creeping or erect type in ground-cover chrysanthemum likely controlled by an incomplete dominance major gene as well as polygene. A RAPD marker A-10555 linked to creeping gene were screened, the validity of this RAPD maker was verified by replicate tests and testing individual plant in F1 population, the maker was 7.96 cM far from the loci controlling creeping/erect [ Conclusion ] It is feasible to divide plant type into creeping, erect or intermediate types by branching angle of main branch, F1, F2 and BC1 population were useful population for segregation investigation of plant type in ground-cover chrysanthemum. The marker obtained in this study is closely linked to loci controlling creeping or erect, and is promising in molecular assisted breeding.