01779naa a2200265 a 450000100080000000500110000800800410001910000220006024500880008226000090017052010410017965000160122065000180123665000140125465000110126865000170127965000190129665000130131565300170132865300260134570000170137170000170138870000180140577300900142310489912010-12-01       2006    bl uuuu     u00u1 u    #d1 aPAGLIARINI, M. S.  aInterchanges in popcorn (Zea mays L.) involving the nucleolus organizer chromosome.  c2006  aThe analysis of microsporogenesis in endogamous plants of popcorn (S5 to S7) showed several and distinct interchanges which involve the nucleolus organizer (chromosome 6). This detection of cells with interchanges was facilitated by the presence of two nucleoli of different sizes in contrast to normal ones with a single big nucleolus. Interchange points do not always seem to be at the same place. Whereas in several situations the interchange point clearly involved more than two chromosome pairs, a simple terminal translocation seemed to occur in others. During diplotene, a cross-shaped configuration connected with the nucleoli was observed in some meiocytes. Some heteromorphic bivalents were found during diakinesis, after which meiosis progressed normally to the end and gave rise to apparently normal tetrad with one normal nucleolus in each microspore. Tests of pollen viability in fixed pollen grains showed 100% stainability in normal and in affected plants. This is the first report on chromosome interchanges in popcorn.  aAgricultura  aBiotecnologia  aGenética  aMeiose  aMilho Pipoca  aTranslocação  aZea Mays  aCromossomo 6  aOrganizador nucleolar1 aRICCI, G. L.1 aSILVA, N. da1 aSCAPIM, C. A.  tCrop Breeding and Applied Biotechnology, Londrinagv. 6, n. 3, p. 203-208, June 2006.