RT Journal Article T1 Chromosome Instabilities and Programmed Cell Death in Tapetal Cells of Maize With B Chromosomes and Effects on Pollen Viability A1 González Sánchez, Mónica A1 Rosato, Carmen Luisa Marcela A1 Chiavarino, Mauricio A1 Puertas, María AB B chromosomes (B’s), knobbed chromosomes, and chromosome 6 (NOR) of maize undergo nondisjunction and micronucleus formation in binucleate tapetal cells. These chromosome instabilities are regular events in the program of tapetal cell death, but the B’s strongly increase A chromosome instability. We studied 1B and 0B plants belonging to selected lines for high or low B transmission rate and their F1 hybrids. These lines are characterized by meiotic conservation or loss of B chromosomes, respectively. The female B transmission (fBtl) allele(s) for low B transmission is dominant, inducing micronucleus formation and B nondisjunction. We hypothesize that the fBtl allele(s) induces knob instability. This instability would be sufficient to produce B loss in both meiocytes and binucleate tapetal cells. B instability could, in turn, produce instabilities in all chromosomes of maize complement. To establish whether the chromosomal instabilities are related to the tapetal programmed cell death (PCD) process, we applied the TUNEL technique. PCD, estimated as the frequency of binucleate tapetal cells with TUNEL label, was significantly correlated with the formation of micronuclei and the frequency of pollen abortion. It can be concluded that the observed chromosome instabilities are important to the PCD process and to the development of microspores to form viable pollen grains. SN 1943-2631 YR 2004 FD 2004 LK https://hdl.handle.net/20.500.14352/98878 UL https://hdl.handle.net/20.500.14352/98878 LA eng NO Mónica González-Sánchez, Marcela Rosato, Mauricio Chiavarino, María J Puertas, Chromosome Instabilities and Programmed Cell Death in Tapetal Cells of Maize With B Chromosomes and Effects on Pollen Viability, Genetics, Volume 166, Issue 2, 1 February 2004, Pages 999–1009, https://doi.org/10.1093/genetics/166.2.999 NO Ministerio de Ciencia, Innovación y Universidades (España) DS Docta Complutense RD 6 abr 2025