Identification of putative origin of Iris pumila L. karyotype

Abstract

Aim. The study was aimed at cytogenetic analysis of Iris pumila, I. attica, and I. pseudopumila, comparative study of the karyotypes of these species, as well as identification of putative origin of I. pumila karyotype. Methods. Cytogenetic analysis of root apical meristem, determination of chromosome number in mitotic metaphase plates, anaphase analysis. Results. The chromosome numbers observed were 2n=32 for I. pumila plants from different localities in Ukraine and 2n=16 for I. attica and I. pseudopumila plants from Greece and Italy, respectively. Some of the plants were mixoploids, the smallest proportion of mixoploids was in I. pseudopumila (10.9%) and the largest in I.pumila from all studied populations (60-80%). Anaphase analysis showed the presence of chromosomal aberrations in 2.6% of cells in roots of I. pseudopumila seedlings. The highest level of structural chromosomal aberrations (9.2%) was found in root apical meristem cells of I. pumila seedlings. Conclusions. The chromosome number was established as 2n=32 for I.pumila plants and 2n=16 for I. attica and I. pseudopumila plants. The high level of mixoploidy (60–80% of mixoploid plants) and anaphase chromosomal aberrations (up to 9.2%) was found in apical meristem of I. pumila seedlings. The amphidipiloid nature of I. pumila was established; the karyotype of the species could be formed as a result of a combination of chromosome sets from hypothetical ancestral species I. attica and I. pseudopumila.
 Keywords: Iris pumila L., Iris attica Boiss. & Heldr., Iris pseudopumila Tineo, chromosome number, amphidiploid, mixoploidy.