Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies

Detalhes bibliográficos
Autor(a) principal: Fuzinatto,Veridiana Aparecida
Data de Publicação: 2012
Outros Autores: Pagliarini,Maria Suely, Valle,Cacilda Borges do
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Scientia Agrícola (Online)
Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000600006
Resumo: Hybrids combining desirable traits from divergent parents are the main objective of some Brachiaria (Syn. Urochloa P. Beauv.) breeding programs. There is great interest in the development of apomictic hybrid cultivars that combine desirable genes such as resistance to spittlebugs, high nutritive value, and tolerance to acid soils. Microsporogenesis of six apomictic progenies resulting from a tetraploid (2n = 4x = 36) cross between B. ruziziensis × B. brizantha was evaluated under light microscopy. Genetic recombination, ensured by multivalent chromosome association and crossing-over at prophase occurred in low frequency among progenies, and in one, recombination was almost nonexistent. The percentage of meiocytes with meiotic abnormalities among progenies ranged from 16.6 % to 85.6 %. Besides an observed irregular chromosome segregation typical of polyploid hybrids in these five progenies, putative meiotic mutations characterized as desynapsis and divergent spindle organization occurred in three progenies. These anomalies caused frequent fractionation of the genome into several microspores of different sizes. In Brachiaria, new cultivars must be apomictic to fix the genotype. However, Brachiaria is a pseudogamous apomict, and viable gametes are necessary to produce viable seeds. Considering meiotic behavior, only two progenies are promising for advancement in the breeding program.
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spelling Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progeniesBrachiariamicrosporogenesisbreedingpasturesapomixisHybrids combining desirable traits from divergent parents are the main objective of some Brachiaria (Syn. Urochloa P. Beauv.) breeding programs. There is great interest in the development of apomictic hybrid cultivars that combine desirable genes such as resistance to spittlebugs, high nutritive value, and tolerance to acid soils. Microsporogenesis of six apomictic progenies resulting from a tetraploid (2n = 4x = 36) cross between B. ruziziensis × B. brizantha was evaluated under light microscopy. Genetic recombination, ensured by multivalent chromosome association and crossing-over at prophase occurred in low frequency among progenies, and in one, recombination was almost nonexistent. The percentage of meiocytes with meiotic abnormalities among progenies ranged from 16.6 % to 85.6 %. Besides an observed irregular chromosome segregation typical of polyploid hybrids in these five progenies, putative meiotic mutations characterized as desynapsis and divergent spindle organization occurred in three progenies. These anomalies caused frequent fractionation of the genome into several microspores of different sizes. In Brachiaria, new cultivars must be apomictic to fix the genotype. However, Brachiaria is a pseudogamous apomict, and viable gametes are necessary to produce viable seeds. Considering meiotic behavior, only two progenies are promising for advancement in the breeding program.Escola Superior de Agricultura "Luiz de Queiroz"2012-12-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000600006Scientia Agricola v.69 n.6 2012reponame:Scientia Agrícola (Online)instname:Universidade de São Paulo (USP)instacron:USP10.1590/S0103-90162012000600006info:eu-repo/semantics/openAccessFuzinatto,Veridiana AparecidaPagliarini,Maria SuelyValle,Cacilda Borges doeng2012-11-14T00:00:00Zoai:scielo:S0103-90162012000600006Revistahttp://revistas.usp.br/sa/indexPUBhttps://old.scielo.br/oai/scielo-oai.phpscientia@usp.br||alleoni@usp.br1678-992X0103-9016opendoar:2012-11-14T00:00Scientia Agrícola (Online) - Universidade de São Paulo (USP)false
dc.title.none.fl_str_mv Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
title Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
spellingShingle Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
Fuzinatto,Veridiana Aparecida
Brachiaria
microsporogenesis
breeding
pastures
apomixis
title_short Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
title_full Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
title_fullStr Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
title_full_unstemmed Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
title_sort Meiotic behavior in apomictic Brachiaria ruziziensis × B. brizantha (Poaceae) progenies
author Fuzinatto,Veridiana Aparecida
author_facet Fuzinatto,Veridiana Aparecida
Pagliarini,Maria Suely
Valle,Cacilda Borges do
author_role author
author2 Pagliarini,Maria Suely
Valle,Cacilda Borges do
author2_role author
author
dc.contributor.author.fl_str_mv Fuzinatto,Veridiana Aparecida
Pagliarini,Maria Suely
Valle,Cacilda Borges do
dc.subject.por.fl_str_mv Brachiaria
microsporogenesis
breeding
pastures
apomixis
topic Brachiaria
microsporogenesis
breeding
pastures
apomixis
description Hybrids combining desirable traits from divergent parents are the main objective of some Brachiaria (Syn. Urochloa P. Beauv.) breeding programs. There is great interest in the development of apomictic hybrid cultivars that combine desirable genes such as resistance to spittlebugs, high nutritive value, and tolerance to acid soils. Microsporogenesis of six apomictic progenies resulting from a tetraploid (2n = 4x = 36) cross between B. ruziziensis × B. brizantha was evaluated under light microscopy. Genetic recombination, ensured by multivalent chromosome association and crossing-over at prophase occurred in low frequency among progenies, and in one, recombination was almost nonexistent. The percentage of meiocytes with meiotic abnormalities among progenies ranged from 16.6 % to 85.6 %. Besides an observed irregular chromosome segregation typical of polyploid hybrids in these five progenies, putative meiotic mutations characterized as desynapsis and divergent spindle organization occurred in three progenies. These anomalies caused frequent fractionation of the genome into several microspores of different sizes. In Brachiaria, new cultivars must be apomictic to fix the genotype. However, Brachiaria is a pseudogamous apomict, and viable gametes are necessary to produce viable seeds. Considering meiotic behavior, only two progenies are promising for advancement in the breeding program.
publishDate 2012
dc.date.none.fl_str_mv 2012-12-01
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000600006
url http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162012000600006
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv 10.1590/S0103-90162012000600006
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv text/html
dc.publisher.none.fl_str_mv Escola Superior de Agricultura "Luiz de Queiroz"
publisher.none.fl_str_mv Escola Superior de Agricultura "Luiz de Queiroz"
dc.source.none.fl_str_mv Scientia Agricola v.69 n.6 2012
reponame:Scientia Agrícola (Online)
instname:Universidade de São Paulo (USP)
instacron:USP
instname_str Universidade de São Paulo (USP)
instacron_str USP
institution USP
reponame_str Scientia Agrícola (Online)
collection Scientia Agrícola (Online)
repository.name.fl_str_mv Scientia Agrícola (Online) - Universidade de São Paulo (USP)
repository.mail.fl_str_mv scientia@usp.br||alleoni@usp.br
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