Genetic diversity and relationship of Tunisian castor (Ricinus communis L.) genotypes revealed by SSR markers

Abstract

The aim of this study was to assess genetic diversity within the set of 55 Tunisian castor genotypes using 20 SSR primers. PCR amplification of DNA using 20 primers for SSR analysis produced 141 DNA fragments that could be scored in all 55 genotypes of castor. The number of amplified fragments varied from 4 (Rco 15) to 10 (Rco 29 and Rco 33). Of the 141 amplified bands, all 141 were polymorphic, with an average of 7.05 polymorphic bands per primer. The polymorphism information content (PIC) value varied from 0.719 (Rco 15) to 0.879 (Rco 29), with an average of 0.825 and index diversity (DI) value varied from 0.745 (Rco 15) to 0.881 (Rco 29) with an average of 0.832. 100% of used SSR markers had PIC and DI values higher than 0.7 that means high polymorphism of chosen markers used for analysis. Probability of identity (PI) was low ranged from 0.002 (Rco 29 and Rco 41) to 0.018 (Rco 15) with an average of 0.007. A dendrogram based on UPGMA analysis separated 55 Tunisian castor genotypes into 4 clusters (1, 2, 3, 4). Knowledge on the genetic diversity of castor can be used for future breeding programs for increased oil production to meet the ever increasing demand of castor oil for industrial uses as well as for biodiesel production.