Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2007.553.560SheidaiM. SottodehM. AkbareiB. 42007104Meiotic study was performed in 23 oil seed rape (Brassica napus) cultivars considering chiasma frequency and distribution as well as chromosomes pairing. All cultivars possessed n = 19 chromosome number (4x). Chromosome stickiness occurred in most of the cultivars from early prophase to late telophase-II leading to the formation of laggard chromosomes and micronuclei. The cultivars studied differed significantly in chiasma frequency and distribution as well as chromosomes association indicating their genomic differences. Cluster analysis and ordination based on principal components analysis grouped those cultivars showing meiotic similarities. Some of the cultivars showed the occurrence of B-chromosomes which significantly changed chiasma frequency and chromosome pairing in the cells possessing them. Unreduced meiocytes and pollen grains were observed in some of the cultivars due to cytomixis, anaphase failure and desynapsis.]]>Baptista-Giacomelli, F.R., M.S. Palgliarini and J.L. de Almeida,2000Avena sativa L.).]]>65371378Camacho, J.P.M., T.F. Sharbel and L.W. Beukeboom,2000355163178De-Souza, A.M. and M.S. Palgliarini,1996398589Falistocco, E., T. Tosti and M. Falcinelli,1995Dactylis, one of the origins of 2n gametes.]]>86448453Nirmala, A. and P.N. Rao,199639151175Quicke, D.L.J.,1993Sheidai, M., M.R. Manossorniya and M.R. Ahmadi,2001Brassica napus L.) cultivars in Iran.]]>444651Sheidai, M., Z. Noormohammadi and M.R. Ahmadi,2001Brassica napus) cultivars.]]>44165170Sheidai, M., M. Noormohammadi, N. Kashani and M. Ahmadi,2003Brassica napus L.) cultivars and their hybrids.]]>56387397Villeux, R.,19851985pp: 442pp: 442Vorsa, N. and E.T. Bingham,1979Medicago sativa.]]>21525530