title: ms17: a meiotic mutation causing partial male sterility in a corn silage hybrid.
abstract: Cytological analysis under light microscopy of the  single hybrid P30R50 of silage corn revealed an abnormal pattern of  microsporogenesis that affected the meiotic products. Meiosis progressed  normally until diakinesis, but before migration to the metaphase plate,  bivalents underwent total desynapsis and 20 univalent chromosomes were  scattered in the cytoplasm. At this stage, meiocytes also exhibited a number of  chromatin-like fragments scattered throughout the cell. Metaphase I was  completely abnormal in the affected cells, and univalent chromosomes and  fragments were distributed among several curved spindles. Anaphase I did not  occur, and each chromosome or group of chromosomes originated a micronucleus.  After this phase, an irregular cytokinesis occurred, and secondary meiocytes  with several micronuclei were observed. Metaphase II and anaphase II also did  not occur, and after the second cytokinesis, the genomes were fractionated into  polyads, generating several unbalanced microspores, with various-sized nuclei.  About 35% of the tetrads were abnormal in the hybrid. This spontaneous mutation  had been previously reported in a USA maize line called ms17 and was  found to cause male sterility.
authors.affiliation: Departamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Maringá, PR, Brasil. mspagliarini@uem.br
authors.forename: M S
authors.initials: MS
authors.lastname: Pagliarini
authors.forename: V F
authors.initials: VF
authors.lastname: Souza
authors.forename: N
authors.initials: N
authors.lastname: Silva
authors.forename: C A
authors.initials: CA
authors.lastname: Scapim
authors.forename: M
authors.initials: M
authors.lastname: Rodovalho
authors.forename: M V
authors.initials: MV
authors.lastname: Faria
mesh_terms: D002453:Cell Cycle; D059447:Cell Cycle Checkpoints; D032461:Chromosomes, Plant; D048749:Cytokinesis; D018744:DNA, Plant / Q000235:genetics; D056130:Gametogenesis, Plant; D018745:Genome, Plant; D008540:Meiosis / Q000235:genetics*; D009154:Mutation; D051479:Plant Infertility / Q000235:genetics* / Q000502:physiology*; D012820:Silage; D003313:Zea mays / Q000166:cytology / Q000235:genetics*
chemical_list: D018744:DNA, Plant