Preliminary identification of Citrus changshanhuyou elite genotypes by molecular markers

Random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR) analyses were used in elite genotypes identification of Citrus changshan-huyou and analysis of its origin. 12 out of 100 RAPD primers and 11 out of 105 ISSR primers could generate reproducible polymorphic fragments. The RAPD-PCR and ISSR-PCR assays revealed that 64 bands out of 117 (the percentage of polymorphic bands, PPB=54.7%) and 58 bands out of 94 (PPB = 61.7%) were polymorphic, respectively. ISSR and RAPD produced 15 and 12 genotype-specific and species-specific molecular markers. Analysis of molecular variance (AMOVA) was used to calculate the similarity values according to these polymorphic bands, and a dendrogram was constructed using NTSYS-pc software. Each genotype and species in this study could be distinguished from others, suggesting that DNA profiles based on ISSR and RAPD markers have produced potential diagnostic fingerprints for various species, and also for genotypes. The molecular phylogenetic tree shows that C. changshan-huyou and C. sinensis formed a subcluster, so we can conclude that C. sinensis is an assured parent of C. changshan-huyou. However the largest genetic distance was found between C. grandis and C. changshan-huyou, it might be explained that C. changshan-huyou is the origin of multitude of natural hybrids from C. sinensis, C. grandis and other species of Citrus.