DNA landmarks for genetic diversity assessment in tea genotypes using RAPD markers
Tea (Camellia sinensis) is one of the most important non-alcoholic beverages of the world. Natural genetic diversity in tea has been reduced due to continue selection in favor of desirable traits. The present study was conducted to estimate genetic diversity in tea genotypes cultivated in Pakistan using 20 randomly amplified polymorphic DNA (RAPD) primers. 75 tea accessions from 13 tea genotypes were analyzed. Genetic distance estimates ranged from 0-100% showing high level of diversity among screened genotypes. Unweighted pair group method using arithmetic averages (UPGMA) based cluster analyses of RAPD data clustered all the genotypes into five main groups which showed mixed grouping profile of the samples. However, samples from different plants of particular genotypes were segregated into independent sub-clusters. Broad and narrow leaved genotypes were accommodated in separate sub-clusters. Similarly, samples from narrow leaved genotypes collected from different sites were grouped in different main clusters reflecting the geographical origins of tea samples. Results obtained confirm that RAPD methodology is practically applicable for evaluation of genetic diversity and relationship in tea genotypes.
Key words: Camellia sinensis, genotypes, genetic diversity, randomly amplified polymorphic DNA (RAPD), dendrogram, cluster analysis.