Genetic diversity analysis of citrus cultivars and rootstocks of the north eastern India by RAPD markers

Random amplified polymorphic DNA (RAPD) markers were used to evaluate genetic diversity among 12 cultivars and rootstocks of citrus of the North Eastern India. Ten selected decamer primers produced 97 amplified fragments, all of them except one were polymorphic and 11 were unique to some germplasms. The genetic distance measured based on Squared Euclidean Distance ranged from 16–60%, which showed the presence of low to moderate genetic diversity among the germplasms. By Ward's method of cluster analysis 12 germplasms were classified into two major clusters. All the mandarin orange cultivars viz., Darjeeling mandarin, Khasi mandarin and a wild type formed one of the distinct clusters. Sweet orange cv. Mosambi having its clear genetic identity formed another cluster with the rest of the rootstocks and cultivars. The commercial cultivar of lemon, Pati nimbu showed the closest genetic relations with the commercial cultivar of acid lime, Kagzi lime but showed a moderate distance from cultivar Gandharaj lemon and farther distance from cultivar Assam lemon. The rootstocks Rangpur lime, trifoliate orange and sour orange in order showed closer proximity with the sweet orange cv. Mosambi and that of rough lemon cv. Kata Jamir was with the common acid lime and lemon cultivars. The RAPD markers confirmed the distinction of close cultivars and also the interrelationship among different land races that can be used for the genetic improvement of citrus in this region.