Chromosome Pairing and Cytomixis in Safflower (Carthamus tinctorius L., Asteraceae) Cultivars

Cytogenetic studies concerning karyotype and meiotic analyses were performed in thirty-seven cultivars of C tinctorius grown in Iran. All the cultivars showed 2n=2x=24 chromosome number having meta and sub-meta centric chromosomes ranging in size from 1.55 to 4.63 mu m. The cultivars studied differed significantly in the size of chromosomes and in karyotype formulae indicating the occurrence of quantitative and qualitative changes in their chromosomes. Meiotic analysis showed the occurrence of post pachytene diffuse stage, mostly bivalent formation in metaphase and also the occurrence of quadrivalents due to translocations in some of the cultivars studied. Meiotic abnormalities like chromosomes stickiness, laggard formation, multipolar cells and cytomixis occurred in some of the cultivars leading to pollen sterility and polyploid pollen formation. Grouping of the cultivars based on cytogenetic data showed their genetic differences.