University of Tehran Journal of Sciences, Islamic Republic of Iran 1016-1104 14 2 2003 06 01 MEIOTIC STUDIES OF SOME AVENA SPECIES AND POPULATIONS IN IRAN - 31681 EN Journal Article Eleven populations of five Avena species were analysed for meiotic characters including chiasma frequency and distribution as well as chromosomal association and segregation. Plants of a single population of A. eriantha showed the presence of 2n = 14 (diploid) and 2n = 4x = 28 chromosome number. Populations of A. barbata and A. wiestii possessed n = 14, while populations of A. sterilis ssp. ludoviciana possessed 2n = 6x = 42 (hexaploid) chromosome number. Tetraploid and hexaploid species showed diplontic behavior and formed only bivalents. The species and populations studied differed significantly in the frequency of chiasmata. B-chromosomes occurred in some of the species studied. Cytomixis and chromosome elimination led to aneuploid and unreduced pollen mother cell formation in the species studied. https://jsciences.ut.ac.ir/article_31681_b3f1ba764509b453d6cc48e0969e5cb7.pdf