Genetic analysis between unknown Citrus accessions and commercially important cultivars using ISSR marker

Abstract

Understanding phylogenic relationships and genetic diversity in citrus is considered to be important in clarifying their genetic relationships, germplasm characterization and the registration of new varieties. There are some Citrus accessions in the country citrus collections which have been classified merely based on their morphological traits and much genetic research has not been done. Molecular markers would help to infer their relations with known cultivars. In the present research work, phylogenic relationships among 55 citrus genotypes including 43 unknown local genotypes and 12 commercially important citrus varieties were investigated through ISSR markers. In total, 10 ISSR primers produced 92 polymorphic bands with average of 9.2 bands per primer. Polymorphism percent of each primer varied from 75 in primer BDB(CA)7C to 100 in primer (AC)8YT. Genetic similarities among accessions were calculated according to Jaccard Similarity Index and used to construct a dendrogram based on the unweighted pair groups method arithmetic averages (UPGMA), which put the 55 samples into nine major groups i.e. (A, B, C, D, E, F, G, H and I). Orange, mandarin and 25 unknown genotypes into group A, grapefruit and 9 unknown genotypes into group B, Pummelo, Darabi and seven unknown genotypes into group C, sour orange and an unknown genotype into groups D & E, citron into group F, Eureka lemon into group G, an unknown genotype into group H and sweet lime and Mexican lime into group I were clustered. Genetic diversity and phylogenetic analysis in citrus, provide useful information for further breeding programs, collection, preservation and utilization.

Keywords

• citrus cultivars
• molecular marker
• phylogenetic relationship