Cytological studies on some species of Bromus sect. Bromus [Citologiniai kai kurių Bromus sect. Bromus rūšių tyrimai]. – Botanica Lithuanica, 11(3): 141–150

Seven Bromus L. species belonging to the section Bromus (Poaceae) were studied for meiotic characteristics including chiasma frequency and distribution as well as chromosomal association and segregation. The species studied showed the presence of 2n = 2x = 14 and 2n = 4x = 28 chromosome numbers. The chromosome number of B. rechingeri is a new report. Diploid species of B. brachystachys formed one–two quadrivalents possibly due to the occurrence of heterozygote translocations. Tetraploid species of B. lanceolatus showed diplontic behavior due to their allotetraploid nature while B. rechingeri formed quadrivalents too. Diploid and tetraploid species differed significantly in their cytogenetics, indicating their genomic difference. Almost in all the species studied laggard chromosomes and stickiness were observed, which might bring about some degree of pollen infertility. Chromatin/chromosome migration occurred in most of the species studied, leading to the formation of aneuploid cells as well as meiocytes having double the normal chromosome number which in turn might form unreduced pollen grains.

Keywords: meiosis, cytomixis, pollen, ploidy level, Bromus.