Research Article

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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

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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

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2n gamete; Interspecific hybridization; Meiosis; Pentaploidy; Poaceae

Knowledge about the cytology and reproductive behavior of a species is indispensable for hybridization programs. This is especially true for species belonging to the genus Paspalum, among which apomixis and a wide range of ploidy levels are frequently found. Paspalum conspersum Schrad. is a robust and warm-season perennial bunchgrass native to South America. Previous ... more

L. Janke; F.H.D. Souza; J.F.M. Valls; M.S. Pagliarini
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Hexaploidy; Interspecific hybridization; Meiosis; Poaceae; Polyploidy

Cytological investigation revealed complete asynapsis during microsporogenesis in 2 wild accessions of Paspalum jesuiticum collected in distinct Brazilian regions. Both accessions were hexaploid (2n = 6x = 60) and 60 univalents could be counted at diakinesis. In this phase, the majority of meiocytes exhibited univalents with both chromatids. After alignment at the metaphase plate ... more

R.A.Bernardo Filho; A.C.C. Santos; F.H.D. Souza; J.F.M. Valls; M.S. Pagliarini
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Brachiaria; chromosome elimination; Meiosis; mitosis

Three accessions of Brachiaria brizantha, three of B. humidicola, and two interspecific hybrids between B. ruziziensis and B. brizantha were analyzed with regard to their mitotic behavior in root tips. All these genotypes revealed chromosome elimination or lack of chromosome affinity in previous analyses of microsporogenesis. Analyses of root tips showed a ... more

M.F. Felismino; N. Silva; M.S. Pagliarini; C.B. Valle
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Triatomines are of great concern in public health because they are vectors of Chagas’ disease. This study presents an analysis of the species Triatoma melanosoma. The cytogenetic characteristics of triatomines include holocentric chromosomes, post-reductional meiosis in the sex chromosomes and nucleolar fragmentation in the meiotic cycle. The methodology utilized consisted of the ... more

V.B. Bardella; M.T.V. Azeredo-Oliveira; E. Tartarotti
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Meiosis; Moringa oleifera; Pollen viability; Tripolar spindles; Unreduced gametes

Although originally from India, Moringa oleifera is now cultivated throughout most of the tropics, including Brazil. Despite its multipurpose value for food and traditional medicine, little is known about the meiotic behavior and pollen viability of M. oleifera. We evaluated microsporogenesis and pollen viability in eleven plants grown in southern Brazil (Maringá, Paraná ... more

N. Silva; A.B. Mendes-Bonato; J.G.C. Sales; M.S. Pagliarini
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Acledra; Heteroptera; Holokinetic chromosomes; Karyotypic variation; Meiosis; Pentatomidae

Acledra comprises 15 taxonomically identified species, most of which are crop pests. This is the first cytogenetic study of species of this genus. Acledra kinbergii and A. modesta showed the modal number of the Pentatomidae (2n = 14 = 12 + XY), while A. bonariensis had a reduced complement (2n = 12 = 10 + XY), with a markedly larger autosomal ... more

P.J. Rebagliati; L.M. Mola
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Chromosome behavior; Genomic in situ hybridization; Meiosis; mitosis; Rye; Wheat

The dynamics of rye chromosomes during mitosis and meiosis was analyzed in a subset comprising 33 F3 lines from the cross of wheat, Psathyrostachys huashanica amphiploid (AABBDDNsNs) and hexaploid triticale (AABBRR), as visualized by genomic in situ hybridization. The results indicated that 31 of the total lines contained 4-14 rye chromosomes. Twenty-eight ... more

Q. Xie; H. Kang; D.L. Sparkes; S. Tao; X.M. Fan; L. Xu; X. Fan; L. Sha; H. Zhang; Y. Wang; J. Zeng; Y. Zhou
11/28/2012
Chromosome number; Meiosis; Mesosetum chaseae; Microgametogenesis; Pollen viability; ‘Grama-do-cerrado’

The genus Mesosetum is a primarily South American genus with 42 species. Mesosetum chaseae, regionally known as ‘grama-do-cerrado’, is abundant in the Pantanal Matogrossense (Brazil); it is a valuable resource for livestock and for environmental conservation. We collected specimens from the Nhecolandia sub-region of the Brazilian Pantanal, located in Corumbá, Mato Grosso ... more

L.A.C. Silva; M.S. Pagliarini; S.A. Santos; N. Silva; V.F. Souza

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