Genetic Analysis And Molecular Marker Of Creeping Habits In Ground-cover Chrysanthemum

ground-cover chrysanthemum have characteristics of creeping or low plant type, multi-branch,strong resistance,better adaptability,rapid prototyping,strong coverage ability,dense flower and so on.along with comprehensive functions of afforestation, beautification,color and fragrance,the prospect of garden application is extremely broad. 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 F₁ were randomly selected,and selfcross was made to generate the F₂ population.BC₁ population was obtained from back cross of the selected individuals with 03(6)-12.In order to provide bases for molecular assisted breeding,and for cloning creeping habit related genes from the ground-cover chrysanthemum,we studied the inheritance traits of creeping habit,and screened the RAPD markers related to this habit.The main results are as following:1.The segregation ratio of different plant type was documented in seven populations. 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.2.The gene bulk of creeping and erect plant type in F₁ population were constructed by using bulked segregant analysis(BSA) method.200 RAPD arbitrary primers were used to screen creeping habit related molecular markers.A RAPD marker A-10₅₅₅ linked to creeping gene were screened,the validity of this RAPD maker was verified by replicate tests and screening individuals in F₁ progeny,the maker was 7.79 cM far from the loci controlling creeping /erect.The marker obtained in this study is closely linked to loci controlling creeping or erect,and is promising in molecular assisted breeding.3.The specific DNA marker A-10₅₅₅ was recovered,and then inserted into pGEM-T Easy Vector plasmid,and finally transported into E.coli.DH5α.After the specific band was cloned and sequenced,a pair of 18-base specific primers was designed.The SCAR analysis of parents and 152 F₁ plants displayed that the result of amplification with SCAR is identical with that of RAPD.the size of this marker was 555 bp,which was designated as SCA10₅₅₅。The reliability of result showed that the marker was converted into SCAR marker successfully.