THE GENETIC diversity relationship was studied among ten cultivars of Catharanthus roseus depending on geographic locations in Egypt (five governorates: Marsa Matruh, Kafr ash-Shaykh, Port Said, Cairo, and Bur-Safajah) and two colors of flowers (white and pink) using RAPD and ISSR assay. In the RAPD assay, four primers amplified gave a low polymorphism (30%) and (18%) in ISSR markers.
The highest value of similarity was 1, while the lowest value of similarity indexed was 0.539. In ISSR analysis, 17.6% polymorphism was observed, the highest value of similarity was 1 and the lowest value of similarity index recorded was 0.106. The combined RAPD and ISSR analysis data revealed the highest similarity observed (0.984) but, the least similarity was 0.448. The primer OP-L13 only was given two specific markers in RAPD assay. The present study revealed that RAPD would be a useful assay compared to the ISSR phylogenetic assay for studies to identify the genetic diversity of the genome. The Principle component analysis (PCA) of RAPD and ISSR assays using 4 primers (both of them) was studied among ten genotypes cultivars of Catharanthus roseus plant. The results showed that the RAPD assay has given three clusters with 72.66 and 25.35% of the variance, the ISSR assay has given two clusters with 75.55 and 24.26% of the variance. On the other hand, the combined RAPD and ISSR assays have given the three clusters with 67.01 and 20.74% of the variance.