Assessment of genetic diversity in cultivated Indian tea (Camellia sinensis (L.) Kuntze)

Tea is an important beverage crop in India and worldwide.The tea germplasm in India includes three different types of tea cultivars, namely, China type, Assam type and Cambod type.Present study was conducted to evaluate the degree and organization of genetic diversity in cultivated Indian tea.The technique used was based on random amplified polymorphic DNA-PCR (RAPD-PCR) markers analysis.34 ten decamer primers were used generating 359 reproducible bands and among these, 321 (89.42%) bands were polymorphic.The genetic diversity among cultivars as calculated from Nei's index averaged 0.28 varying from 0.07 to 0.50.Calculation of Shannon index of diversity revealed an average of 0.44 varying from 0.28 to 0.56, indicating that Camellia sinensis (L.) Kuntze maintains a relatively high degree of genetic diversity at the cultivar level.Analysis of genetic dissimilarity showed that genetic differentiation occurred among studied cultivars, which supports the possibility of current ex-situ conservation strategies.Dendrograms were generated using UPGMA method revealing three distinct clusters of Cambod, Assam and China type, which is in agreement with the known taxonomical classification of tea.A study of correspondence analysis of the data also revealed a clear picture of polymorphism detected among the said cultivars.These results suggest that the RAPD-PCR method is a rapid and effective means to evaluate the genetic diversity among a large number of tea cultivars and help devise sampling strategies to compliment classical morpho-agronomic descriptors and conservation of Indian tea cultivars.