Chromosome stickiness impairs meiosis and influences reproductive success in Panicum maximum (Poaceae) hybrid plants

Abstract

ABSTRACT. Chromosome stickiness has been studied in several species of higher plants and is characterized by sticky clumps of chromatin resulting in sterility. Chromosome stickiness was recorded in Panicum maximum hybrid plants that were cultivated in the field. In the meiocytes affected, chromosomes clumped into amorphous masses that did not orient themselves on the equatorial plate, and anaphase I disjunction failed to occur. After a normal cytokinesis, the masses of chromatin were divided between both daughter cells. Metaphase and anaphase of the second division also did not occur, and after the second cytokinesis, polyads were formed. This abnormality arose spontaneously. Abnormalities that cause male sterility are an important tool for obtaining hybrid seeds in plant breeding. This is the first report of an abnormality affecting pollen viability in P. maximum. This finding can open a new opportunity in the breeding program of this species that is devoted to hybridization where manual cross-pollination is difficult and time consuming.

High-Resolution Linkage Map With Allele Dosage Allows the Identification of Regions Governing Complex Traits and Apospory in Guinea Grass (Megathyrsus maximus)

“…Autotetraploids may undergo this type of segregation when in multivalent pairing, two pairs of chromatids pass to the same pole in anaphase I of meiosis (Haynes and Douches, 1993). In guinea grass, irregular chromosome segregation has already been verified in cytogenetic analysis in hybrids and parents from the breeding program of the Embrapa Beef Cattle (Pessim et al, 2010;Pessim et al, 2015). The distribution of the markers with DR between the dosage types was proportional to the number of SNPs with each configuration.…”

Nanomaterials Induced Genotoxicity in Plant: Methods and Strategies

“…Among the major effects observed from the exogenous genotoxic effects on plant genomes, the chromosomal aberrations, which are the result of structural and numerical chromosome changes, preferentially within heterochromatic regions, are composed mainly of repetitive DNA sequences [ 21 ]. Optical, fluorescence and confocal laser scanning microscopy techniques are able to highlight aberrations at the level of the chromosome structure, including chromosomal breaks, sticky, multipolar, and laggard chromosomes, as well as micronucleus formation [ 22 , 23 , 24 ].…”

Genomic Selection in Tropical Forage Grasses: Current Status and Future Applications

“…Diploid sexual individuals of M. maximus were collected in Korogwe, Tanzania, and artificially duplicated (Jank et al, 2014). The cytogenetic evaluation of autotetraploid (2n = 4x = 32) sexual and supposedly segmental allopolyploid apomictic plants revealed a low-to-moderate rate of meiotic abnormalities among sexual (5%-31%) and apomictic (7%-11%) parents (Pessim et al, 2010(Pessim et al, , 2015. Hybrids originating from a single cross showed abnormal cells at a rate ranging from 16% to 52% (Pessim et al, 2010(Pessim et al, , 2015.…”

“…The cytogenetic evaluation of autotetraploid (2n = 4x = 32) sexual and supposedly segmental allopolyploid apomictic plants revealed a low-to-moderate rate of meiotic abnormalities among sexual (5%-31%) and apomictic (7%-11%) parents (Pessim et al, 2010(Pessim et al, , 2015. Hybrids originating from a single cross showed abnormal cells at a rate ranging from 16% to 52% (Pessim et al, 2010(Pessim et al, , 2015. The frequency of meiotic abnormalities found in M. maximus is lower than that reported in the tetraploid Urochloa (2n = 4x = 36) interspecific hybrids, which ranged from 18% to 82% (Risso-Pascotto et al, 2005;Mendes-Bonato et al, 2006Fuzinatto et al, 2007).…”