Research Article

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11/08/2002
Apomixis origin; Centers of diversity; Electrophoresis; Evolution; Interspecific hybridization; Polyploidy; Unreduced gametes

About 98 species of Manihot are known. All of them are native to the New World and are concentrated in four regions in Brazil and Central America. All the Manihot species so far examined have 2n = 36 chromosomes. Interspecific hybrids between cassava and its wild relatives show relatively normal meiosis, and further generations can be obtained. Electrophoresis shows ... more

N.M.A. Nassar
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
01/11/2011
Interspecific hybridization; Passiflora L.; Paternity test; RAPD

Several interspecific Passiflora hybrids are produced in the northern hemisphere for the ornamental plant market. In Brazil, production of passion flower hybrids is limited to the introgression of genes into the main cultivated species, yellow passion fruit, to be used as rootstocks. Confirmation of hybridization in the initial developmental stage is important for breeding ... more

L.D.H.C.S. Conceição; M.M. Souza; C.B.M. Cerqueira-Silva; R.X. Corrêa; G.O. Belo; S.F. Santos
10/24/2013
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
01/17/2014
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
08/14/2019
Apomixis; beta Carotene; Interspecific hybridization; Periclinal chimera; Polyploidization; Protein and essential amino acid content

Through use of interspecific hybridization, and in some cases followed by polyploidization, cassava cultivars combining various desirable characteristics have been developed in Brazil. These range from high protein content and increased essential amino acids to tolerance to drought. Some cultivars have highly apomictic behavior. Others show tolerance to bacterial ... more

N.M.A. Nassar
12/11/2007
Amino acids; Apomixis; Drought; Protein

Wild cassava relatives are perennials and vary in growth pattern from nearly acaulescent subshrubs to small trees. They have been used as a source of useful characters such as high protein content, apomixis, resistance to mealybug and mosaic disease, and tolerance to drought. Indigenous clones are a potential source of β-carotene and lycopene. Apomixis genes have been transferred to the crop ... more

N.M.A. Nassar
08/07/2006
Apomixis; Microsatellite; Open pollination; Protogeny; Second generation progeny

Cassava is the main staple for more than 800 million people in the tropics. It is propagated vegetatively by stem cuttings, which maintains superior genotypes but favors disease accumulation and spread. In this report, we present the results of the screening of the progeny and the second generation of the clone UnB 307 for apomixes using microsatellites. A total of 29 plants were ... more

N.M.A. Nassar; D.C. Kalkmann; R. Collevatti
08/11/2006
Apomixis; Interspecific crosses; Polyploidy

A new species was synthesized artificially by chromosome doubling in a hybrid. The ensuing polyploid type exhibits an apomictic nature and maintains its morphological characteristics in the progeny. It showed a frequency of multiembryonic sacs of 29% in the ovules examined, whereas sacs were absent in the diploid type.

*In honor of deceased Professor Vieira who dedicated a part ... more

N.M.A. Nassar
11/29/2005
Apomixis; Molecular marker; Satellite technique

Apomixis genes have been successfully transferred to cassava (Manihot esculenta) by hybridizing it with the wild species, M. glaziovii. The interspecific hybrid of cassava and M. glaziovii was exposed to open pollination during three subsequent generations. Seven sibs and the maternal progenitor of the fourth generation were genotyped using five ... more

N.M.A. Nassar; R.G. Collevatti

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