MOLECULAR ASSESSMENT OF GENETIC DIVERSITY IN SOME CANOLA HOMOZYGOUS LINES

In order to assess genetic diversity among ten homozygous lines of Canola, eight RAPD and five ISSR primers as well as two various combinations of Triple-RAPD were successful in generating reproducible and reliable amplicons. A total of 115 amplicons were amplified using all molecular marker techniques applied in this study, 59 (51.3%) of them were polymorphic of which 21 (18.3%) were unique markers. ISSR technique was the best in terms of the average resolving power Rp (13.6) and number of marker amplicons/PCR reaction (1.8). From all of the targeted microsatellites by ISSRs, the repetitive motif (GA)n was more frequent from all repetitive motifs targeted by the other ISSR primers. Highly significant positive correlations were found for molecular distance among all of these molecular marker techniques and combined data, which indicates the reliability of the combined data for molecular distances in accurate assessment for genetic diversity and identifying the genetic relationships between all studied homozygous lines in canola. Accordingly, Cluster analysis and Principal Coordinate (PCo) analysis based on combined data were used for indicating degree of similarity which was high between all the studied homozygous lines. Moreover, PCo analysis have managed to divide these lines into four groups indicating that PCo analysis was succeeded in assessment of genetic diversity and description of heterogeneity within studied lines. On the other hand, the genetic fingerprint for all homozygous lines of canola was performed as DNA-Profile diagram, showing that the amplicons per homozygous line were differentiated for each other with average of 93.3 amplicons and with an appropriate number of diverse molecular markers, indicating that DNA-Profile also is a useful tool for molecular identification. Based on that, these techniques have the potential to identify specific markers for homozygous lines of canola, which indicates the possibility of using these markers as reliable resources for breeding and improvement of canola.