Molecular characterization and genetic diversity analysis of citrus cultivars by RAPD markers

Random Amplified Polymorphic DNA (RAPD) markers were used to evaluate genetic similarity and interrelationship among 18 citrus cultivars, including 13 species and 5 hybrids. Out of 40 decamer primers screened, 25 were selected which produced 250 markers; of which 231 were polymorphic and some species or cultivar specific RAPD markers. The Jaccard coefficient was used to calculate the genetic similarity. UPGMA was used to generate the dendrogram which clearly separated Jatti-Khatti from all major clusters at a similarity coefficient of 0.61. The average genetic similarity value observed across all the genotypes was 0.63, with the 2 sweet orange cultivars, Jaffa and Blood red, showing maximum similarity (82%). The Jatti-Khatti and King Mandarin were found to be genetically most diverse. The genetic variation between cultivars was quite high and revealed their different origins.