 
         
         
         Abstract
         
         The genus Cymbopogon comprises about 140 species, which produce characteristic aromatic essential oils.
            However, the phenotypic identification of species of Cymbopogon has been difficult as a result of widespread occurrence of natural variants, which
            differ in ploidy levels and chemotaxonomic complexities. Therefore, we have developed
            a set of simple sequence repeat markers from a genomic library of Cymbopogon jwarancusa to help in the precise identification of the species (including accessions) of Cymbopogon. For this purpose, we isolated 16 simple sequence repeat containing genomic deoxyribonucleic
            acid clones of C. jwarancusa, which contained a total of 32 simple sequence repeats with a range of 1 to 3 simple
            sequence repeats per clone. The majority (68.8 %) of the 32 simple sequence repeats
            comprised dinucleotide repeat motifs followed by simple sequence repeats with trinucleotide
            (21.8 %) and other higher order repeat motifs. Eighteen (81.8 %) of the 22 designed
            primers for the above simple sequence repeats amplified products of expected sizes,
            when tried with genomic DNA of C. jwarancusa, the source species. Thirteen (72.2 %) of the 18 functional primers detected polymorphism
            among the three species of Cymbopogon (C. flexuosus, C. pendulus and C. jwarancusa) and amplified a total of 95 alleles (range 1 - 18 alleles) with a PIC value of 0.44
            to 0.96 per simple sequence repeat. Thus, the higher allelic range and high level
            of polymorphism demonstrated by the newly developed simple sequence repeat markers
            are likely to have many applications such as in improvement of essential oil quality
            by authentication of Cymbopogon species and varieties and mapping or tagging the genes controlling agronomically
            important traits of essential oils, which can further be utilized in marker assisted
            breeding.
         
         
         
         Abbreviations
         
         SSR: Simple sequence repeat
         
         
         DNA: Deoxyribonucleic acid
         
         
         PCR: Polymerase chain reaction
         
         
         dNTP: Deoxynucleotide triphosphate
         
         
         EST: Express sequence tag
         
         
         QTL: Quantitative trait loci
         
         
         PIC: Polymorphic information content
         
         
         MAB: Marker assisted selection
         
         
         LB: Luria-Bertani
         
         
         
            
Key words
         
         
            Poaceae - 
               Cymbopogon species - genomic library - SSR markers - polymorphism
               
          
      
    
   
      
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Dr. Jitendra Kumar
            Department of Genetics & Plant Breeding
            
            Ch. Charan Singh University
            
            Meerut-25004
            
            India
            
            eMail: jitendra_kumar_2k1@rediffmail.com