RESEARCH ARTICLE Genetic variation among populations of wild safflower, Carthamus oxyacanthus analyzed by agro-morphological traits and ISSR markers Mohammad R. Sabzalian Æ Aghafakhr Mirlohi Æ Ghodratollah Saeidi Æ Mohammad T. Rabbani Received: 8 October 2008 / Accepted: 30 March 2009 / Published online: 28 April 2009 Ó Springer Science+Business Media B.V. 2009 Abstract Wild species of safflower, Carthamus oxyacanthus Bieb., is highly crossable with cultivated species, C. tinctorius L. and could be directly exploited in broadening safflower gene pool and improving the crop for biotic and abiotic stress environments. In this study, genetic diversity among accessions of C. oxyacanthus and their relationships with cultivated safflower were evaluated using agro- morphological traits and polymorphic inter-simple sequence repeats (ISSR) markers. Significant varia- tion was observed among accessions particularly for seeds per capitulum, seed yield per plant, harvest index and capitula per plant. Cluster analysis based on agro-morphological traits classified the wild accessions in two groups according to their geo- graphical regions, and separated them from the cultivated genotypes. ISSR marker also revealed a high genetic variation among the accessions, and cluster analysis based on this marker divided geno- types into four groups, with cultivated ones in a separate clade. Genetic variation observed among the wild safflower germplasm at the DNA level was higher than the agro-morphological traits, indicating that ISSR is an effective marker system for detecting diversity among safflower genotypes and their genetic relationships. Accessions of C. oxyacanthus with high genetic relationship to cultivated species could be used for interspecific hybridization in breeding programs of safflower. Keywords Carthamus Á Genetic variation Á ISSR Á Wild safflower Introduction Safflower (Carthamus tinctorius L.) is gaining importance as an oil seed crop in many countries worldwide. The crop has been traditionally grown for its flower used in coloring and flavoring foods, making dye and medicinal applications. In recent years, it has been grown as a source of vegetable oil for human consumption and industrial purposes (Li and Mu ¨ndel 1996). World production of safflower is lower than other oil seed crops due to lower seed yield and a series of biotic stresses that limit its productivity (Ashri 1971a, b; Knowles 1975; Li and Mu ¨ndel 1996). These limitations can be overcome by breeding programs providing there is enough genetic variation for the traits in the germplasm. Genetic variation has been previously reported in safflower for agronomic traits (Amini et al. 2008; Ashri 1975; Jaradat and Shahid M. R. Sabzalian Á A. Mirlohi (&) Á G. Saeidi Á M. T. Rabbani Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, 84156-83111 Isfahan, Iran e-mail: mirlohi@cc.iut.ac.ir 123 Genet Resour Crop Evol (2009) 56:1057–1064 DOI 10.1007/s10722-009-9426-2