Authors: M.P. Lavinscky, M.M. Souza, G.S. Silva and C.A.F. Melo
The analysis of meiotic behavior has been widely used in the study of plants as they provide relevant information about the viability of a species. Meiosis boasts a host of highly conserved events and changes in genes that control these events will give rise to irregularities that can alter the normal course of meiosis and may.. Read More»
Authors: L. Janke1, F.H.D. Souza2, J.F.M. Valls3 and M.S. Pagliarini1
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 Ameri.. Read More»
Authors: K.C.C. Alevi1, P.P. Mendon�§a1, N.P. Pereira1, J.A. Rosa2 and M.T.V. Azeredo-Oliveira1
Triatoma melanocephala is a rare species of Hemiptera. It belonged to the Brasiliensis subcomplex and presents morphological characteristics very close to those of Triatoma vitticeps. We investigated spermatogenesis of T. melanocephala and compared it with that of T. vitticeps in order to determine whether these organisms have similar cytogenetic characte.. Read More»
Authors: J.R. Luo, J.M. Van Tuyl, P. Arens and L.X. Niu
In order to determine the reasons for pollen sterility in lily hybrids, four diploid sterile Oriental x Trumpet (OT) lily cultivars (‘Nymph’, ‘Gluhwein’, ‘Yelloween’, and ‘Shocking’) were used to investigate the meiotic chromosome behaviors in pollen mother cells (PMCs), using genomic in situ hybridization a.. Read More»
Authors: M.M.U. Castanhole, L.L.V. Pereira, H.V. de Souza and M.M. Itoyama
We examined the course of spermatogenesis and the meiotic chromosome complements in aquatic species of true bugs, Heteroptera. The chromosome complement of the Veliidae species was 2n = 39 (38A + X0) and 23 (22A + X0) in Rhagovelia whitei and Rhagovelia sp, respectively, and in the species of the Notonectidae (Martarega sp) it.. Read More»
Authors: M.M.U. Castanhole
Aspects of spermatogenesis and nucleolar behavior were analyzed in Brachymetra albinerva, Cylindrostethus palmaris, Halobatopsis platensis, Limnogonus aduncus (Gerridae), Martarega sp (Notonectidae), Rhagovelia whitei, and Rhagovelia sp (Veliidae). The testicles are rounded (Veliidae), elongated (Gerridae) or spiral (Notonectidae) and have a transparent m.. Read More»
Authors: W. Staiber
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 somati.. Read More»
Authors: K.R. Boldrini, M.S. Pagliarini and C.B. Valle
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. Mul.. Read More»
Authors: R.A. Bernardo Filho, A.C.C. Santos, F.H.D. Souza, J.F.M. Valls and M.S. Pagliarini
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 b.. Read More»
Authors: C.M.P. Paula, K.G. Figueiredo, F. Souza Sobrinho, F.R.G. Benites, L.C. Davide1and V.H. Techio
The genus Brachiaria contains species that have great economic importance in the Brazilian agricultural sector, as they enable cattle ranching on acid and poor soils with species that are resistant to spittlebugs and form crop-livestock-forest integration systems. The genus mainly consists of tetraploid (2n = 4x = 36) and apomictic species such as B. decu.. Read More»