Research Article

Related GMR Articles

10/05/2007
Brachiaria; Breeding program; Microsporogenesis; Sexual hybrids

Three sexual interspecific hybrids of Brachiaria (HBGC076, HBGC009, and HBGC014) resulting from crosses between B. ruziziensis (female genitor) and B. decumbens and B. brizantha (male genitors) produced by Embrapa Beef Cattle in the 1980s were cytologically analyzed by conventional methods for meiotic studies. The cytogenetic analysis showed the ... more

V.A. Fuzinatto; M.S. Pagliarini; C.B. Valle
11/27/2014
Genetic divergence; interspecific hybrid; Joint analysis; Morphoagronomic characterization; Ward-modified location model (MLM) method

Morphological characterization is the most accessible and used method to quantify the genetic diversity of the available germplasm. The multivariate statistical method is highly important for this purpose. This study aimed to characterize parents and hybrids of Passiflora according to morphoagronomic descriptors and estimate the genetic divergence between them based on the joint ... more

E.A. Santos; A.P. Viana; J.C.O. Freitas; M.M. Souza; C.L. Paiva; D.L. Rodrigues; R.F. Tavares
10/05/2007
Combining ability; Endogamy; Inbred lines; Microsporogenesis; Popcorn

Endogamy places genes for several characteristics in homozygosis, which include those related to meiosis causing abnormalities that may impair gamete viability. An original population (S0) of popcorn (CMS-43) produced by Embrapa Maize and Sorghum was self-pollinated for seven years, generating inbred lines (S1 to S7). Conventional studies of microsporogenesis revealed ... more

G.C.L. Ricci; N. Silva; M.S. Pagliarini; C.A. Scapim
09/30/2007
Brachiaria humidicola; Breeding program; Cytokinesis; Forage grass; Microsporogenesis

Microsporogenesis was evaluated in the Brachiaria humidicola collection of the Embrapa Beef Cattle Center, represented by 60 accessions. One accession (H121) presented an abnormal pattern of cytokinesis that had never been reported in this genus. Among 900 meiocytes analyzed in the first division, 10.7% underwent precocious and multiple cytokinesis in metaphase I, ... more

E.V. Adamowski; K.R. Boldrini; M.S. Pagliarini; C.Bdo Valle
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
12/08/2006
Allopolyploidy; Brachiaria brizantha; Forage grass; Microsporogenesis; Pollen viability

In the hexaploid (2n = 6x = 54) accession B176 of Brachiaria brizantha, one cytological characteristic differentiated it from the other accessions previously analyzed with the same ploidy level. Nearly 40% of meiocytes displayed the chromosome set arranged at two metaphase plates at the poles of the cell, close to the membrane. In these cells, both metaphase plates were ... more

C. Risso-Pascotto; D.V. Mendes; N. Silva; M.S. Pagliarini; C.B. Valle
12/07/2010
Brachiaria decumbens; Evolution; Genome elimination; Microsporogenesis; Natural hybridization; Polyploidy

Polyploidy is a prominent and significant force in plant evolution, taking place since ancient times and continuing until today. Recent cytogenetic studies in the genus Brachiaria using germplasm collected from wild African savannas in the 1980s revealed that most species and accessions within species are polyploid. Diploid, tetraploid, and pentaploid accessions have been found. ... more

G.C.L. Ricci; 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
01/17/2012
Cytomixis; Houttuynia cordata; Meiosis; Microsporogenesis; Polyploidy

Houttuynia cordata (Saururaceae) is a leaf vegetable and a medicinal herb througout much of Asia. Cytomixis and meiotic abnormalities during microsporogenesis were found in two populations of H. cordata with different ploidy levels (2n = 38, 96). Cytomixis occurred in pollen mother cells during meiosis at high frequencies and with variable degrees of chromatin/ ... more

J.Z. Guan; J.J. Wang; Z.H. Cheng; Y. Liu; Z.Y. Li
01/17/2012
Cytomixis; Meiosis; Microsporogenesis; Pinellia ternata; Polyploidy

Pinellia ternata is an important traditional Chinese medicinal plant. Its different populations in China have various ploidy levels, based on x = 13, as well as extensive aneuploid series. The microsporogenesis process was observed in specimens from three populations from three regions of Hubei Province; they were characterized by normal and abnormal meiotic divisions in ... more

Y. Liu; R.K. Hui; R.N. Deng; J.J. Wang; M. Wang; Z.Y. Li

Pages