2022 Volume 87 Issue 2 Pages 119-122
Two accessions were recognized in the species of Cousinia lactifelora Rech. f. Accession A had n=12 and accession B showed the presence of 0 to 10 B-chromosomes at various stages of meiosis in addition to n=12 chromosomes. These B-chromosomes were smaller than the A-chromosomes and there existed as univalent and bivalents. Association of B-chromosomes with A-chromosomes occurred in less than 0.5% at metaphase I. This phenomenon is reported here for the first time. Analysis of chromosome behavior at meiosis showed that the presence of B-chromosomes decreases chiasma frequency in A-chromosomes. The effects of B-chromosomes in odd and even numbers are different. Comparison between plants with B-chromosomes and plants without B-chromosomes suggested that the effect of B-chromosomes was on pollen stainability. It seems that the presence of B-chromosomes may be responsible for the reduction of pollen stainability in C. lactiflora.
