Molecular markers in assessing genetic variation of Indian citron ( Citrus medica L.) cultivars collected from different parts of India

Genetic diversity of forty six representative accessions of Citrus medica L. (Rutaceae) was estimated using 17 (RAPD) random amplification of polymorphic DNA and 11 inter simple sequence repeat (ISSR) markers. A total of 213 RAPD and 105 ISSR bands were generated, out of which, 175 (RAPD) and 77 (ISSR) bands were polymorphic. Polymorphism percentage of RAPD (82%) was comparatively higher than ISSR (73%). Genetic similarity value was found in the range of 0.49 to 0.96 (average 0.73), 0.38 to 0.99 (average 0.69) and 0.47 to 0.96 (average 0.72) in RAPD, ISSR and combined data analyses, respectively. Moderately high levels of polymorphism and genetic similarity within C. medica suggested that citron cultivars have a significant level of genetic diversity. A dendrogram generated based on unweighted pair group method of arithmeticaverage (UPGMA) separated all the accessions into two main clusters. The placement of C. medica accessions in various sub-clusters and groups in the dendrogram was based on molecular differentiation of individual accessions rather than their geographical origin. Both, RAPD and ISSR analyses were able to identify elite genotypes of C. medica with unique accession specific DNA fragments. Thus, both the markers can be utilized for inferring the extent and distribution of genetic diversity in C. medica.