Study on Identification of Five Citrus Sinensis Cultivars Based On Similarity / Diversity in Some Genetic Parameters of Their Molecular DNA Profiles Using IRAP-PCR technique

      The present study was carried out on five sweet orange Cvs., namely White Khalili, Red Khalili, Succari, Navel and Mazizi to throw Their some light on genetic relationships and fingerprinting Profiles via 5 IRAP-PCR Primers. These primers characterized by their higher to moderate degrees of successful in amplification potentiality for reproducible, polymorphic fragments, specific markers and Co-dominated, as well as their discriminatory power. Obtained data regarding the genetic analysis of the 5 orange Cvs. based on the 5 IRAP primers detected that 59 fragments were amplified from which 37 bands were polymorphic with 63%. In addition, 29 bands of these poly morphic ones were positive unique and considered as specific markers. So there 5 sweet orange Cvs didn't give identical DNA fingerprint. The number of total and polymorphic amplified fragments across the 5 orange Cvs by each IRAP Primer showed a considerable variation. Since, the F10&B6 was the superior (21 total and 18 polymorphic fragments), with the highest Polymorphism % (86). In addition, the number of Positive unique DNA fragments (specific markers) generated by the F10&B6 primer varied greatly from one cultivar to another. Herein Navel Orange cv. occurred the highest number followed by Red Khalili, both (White Khalili & Succary) and finally Mazizi i.e, exhibited 5,4,3,3 and 2 specific markers, respectively.
     Results of similarity matrix showed that the highest genetic Similarity (0.877) was existed between both Mazizi &White Khali. Cvs, while the reverse was detected between White Khal. & Red Khal. (0,716). Beside, the UPĢMA dendrogram classified the 5 orange Cvs into two main groups (A &B) i.e, (A.) includes only Succari while (B) was subdivided into (C& D sub- groups) C includes White Khal. only D included E & Fsub-sub clusters, E includes only Navel orange, while F (Mazizi &. Red Khal.) . So the IRAP- PCR an efficient technique for discriminating between Citrus sinensis cultivars even the closely related ones.