Abstract
Magnif 41, a bread wheat cultivar shows very abnormal microsporogenesis, apparently as a consequence of spindle disturbances giving a chaotic picture at the tetrad stage producing pollen grains of different size and frequently showing the presence of micronuclei. Female meiosis seems also to be affected but to a lesser extent than that observed on the male side. High aneuploidy frequency is observed in this cultivar, some of them with very atypical chromosome number or structure. Apparently mitotic spindles are not affected, however in the archesporial cells some disturbances have been detected. The origin of this behaviour seems to be a chromosome mutation inherited like a recessive factor, because it has also been observed in some off-type plants of Sinvalocho M. A., ancestor of this cultivar.