Research Article

Related GMR Articles

12/12/2006
Basic chromosome number; Brachiaria dictyoneura; Cell fusion; Cytokinesis; Interspecific hybridization; Microsporogenesis

Microsporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and ... more

C. Risso-Pascotto; M.S. Pagliarini; C.B. Valle
05/15/2008
Brachiaria; environment; interspecific hybrid; Microsporogenesis

Microsporogenesis in an interspecific Brachiaria hybrid, grown in the field under natural environmental conditions in Brazilian savannas, was analyzed in three distinct years of collection. Several types of meiotic abnormalities were recorded during those three years, but varied in type and frequency depending on the year. The average temperature and rainfall 15 days before collection ... more

V.A. Fuzinatto; M.S. Pagliarini; C.B. Valle
05/15/2012
Brachiaria brizantha; Breeding; Forage grass; Microsporogenesis

The genus Brachiaria comprises more than 100 species and is the single most important genus of forage grass in the tropics. Brachiaria brizantha, widely used in Brazilian pastures for beef and dairy production, is native to tropical Africa. As a subsidy to the breeding program underway in Brazil, cytological studies were employed to determine the chromosome number and to ... more

M.S. Pagliarini; C.B. Valle; E.M. Santos; D.V. Mendes; Z.H. Bernardo; A.B. Mendes-Bonato; N. Silva; V. Calisto
05/11/2007
Apoptosis; Brachiaria hybrid; Chromatin fragmentation; Male sterility; Meiosis; Programmed cell death

Morphological changes have been investigated during plant programmed cell death (PCD) in the last few years due to the new interest in a possible apoptotic-like phenomenon existing in plants. Although PCD has been reported in several tissues and specialized cells in plants, there have been few reports of its occurrence during microsporogenesis. The present study reports a typical ... more

V.A. Fuzinatto; M.S. Pagliarini; C.B. Valle
12/01/2009
Basic chromosome number; Brachiaria humidicola; Forage grass; Genome affinity; Meiosis

Brachiaria humidicola (Poaceae), originally from Africa, is an economically important pasture plant in tropical South America. An accession of B. humidicola (H038) collected from the wild African savanna (Mbeya, Tanzania) showed irregular microsporogenesis. This meiotic behavior was consistent with an allopolyploid origin. Multivalent chromosome association at diakinesis ... more

K.R. Boldrini; M.S. Pagliarini; C.B. Valle
10/06/2009
Chromosome painting; Germ line limited chromosomes; Heterochromatin; Meiosis; Prophase I; Spermatogenesis

In the chironomid Acricotopus lucidus, two cells with quite different chromosome complements arise from the last unequal spermatogonial mitosis, as a consequence of monopolar migration of the so-called germ line limited chromosomes (Ks). The cell receiving all the Ks, in addition to two sets of the regularly segregating somatic chromosomes (Ss), develops into the primary ... more

W. Staiber
07/14/2009
Aquatic Heteroptera; Gerridae; Meiosis; Notonectidae; Nucleolar behavior; Veliidae
M.M.U. Castanhole
02/01/2011
Brachiaria; Breeding; Forage grass; Hybridization; Meiosis

Brachiaria humidicola is a grass adapted to seasonally swampy grasslands in Africa; two cultivars, ‘common’ and Llanero, are widely used in Brazilian pastures. New cultivars are in great demand in order to diversify current production systems to achieve improved quality and yield. Cytological analyses of 55 accessions of this species available from the Embrapa Beef Cattle ... more

K.R. Boldrini; E.V. Adamowski; N. Silva; M.S. Pagliarini; C.B. Valle
10/19/2010
Breeding; Hybrids; Meiosis; Silage corn

In breeding programs, commercial hybrids are frequently used as a source of inbred lines to obtain new hybrids. Considering that maize production is dependent on viable gametes, the selection of populations to obtain inbred lines with high meiotic stability could contribute to the formation of new silage corn hybrids adapted to specific region. We evaluated the meiotic stability of five ... more

V.F. Souza; M.S. Pagliarini; C.A. Scapim; M. Rodovalho; M.V. Faria
08/24/2010
B microchromosome; Heterochromatin; Loricariinae; Meiosis; Rineloricaria pentamaculata; Univalent

We made a cytogenetic study of Rineloricaria pentamaculata from the Tauá Stream, in the Pirapó River sub-basin in Paraná State, Brazil, focused on the occurrence and origins of the B chromosomes. The diploid number varied from 2n = 56 to 2n = 59, due to the presence of 0 to 3 B microchromosomes of the acrocentric type, which were observed in 92.3% of the specimens (N = 12). These ... more

F.E. Porto; A.L.B. Portela-Castro; I.C. Martins-Santos

Pages