Genetic divergence in Tunisian castor bean genotypes based on trap markers

Anotace: In the present study, the representatives of the genus Ricinus communis collected from 12 different parts of Tunisia were differentiated by the DNA fingerprinting patterns using 30 TRAP primers. The efficacy of the TRAP technique in this study is further supported by the obtained PIC values of the primers used in the analysis. PCR amplification of DNA using 30 primers for TRAP analysis produced 490 DNA fragments that could be scored in all 56 genotypes of Tunisian castor. The number of amplified fragments varied from 3 (TRAP 04 x arb 1, TRAP 22 x arb 3 and TRAP 23 x arb 3) to 13 (TRAP 56 x arb 2), and the amplicon size ranged from 100 to 1600 bp. Of the 490 amplified bands, 377 were polymorphic, with an average of 5.71 polymorphic bands per primer. To determine the level of polymorphism in the analysed group of Tunisian castor genotypes polymorphic information content (PIC) was calculated. The lowest values of polymorphic information content were recorded for TRAP 10 x arb 1 (0.555) and the highest PIC values were detected for TRAP 44 x arb 2 (0.961) with an average of 0.770. A dendrogram was constructed from a genetic distance matrix based on profiles of the 30 TRAP primers using the unweighted pair-group method with the arithmetic average (UPGMA). According to analysis, the collection of 56 Tunisian castor genotypes were clustered into five main clusters. Moreover, functional TRAP markers would be efficiently useful in genetic studies for castor genetic improvement.