Nuclear DNA content and chromosome number in Brachiaria spp. genotypes

Timbó, Ana Luiza de Oliveira; Pereira, Rafaela Corrêa; Sobrinho, Fausto Souza; Davide, Lisete Chamma

doi:10.1590/s1806-66902014000100008

Cited by 14 publications

(17 citation statements)

References 15 publications

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“…The amount of DNA was 3.24 pg. Such an estimate gets close to the expected mean values (3.22 pg) if one considers the DNA content of U. ruziziensis and U. brizantha, which are 2.92 and 3.52 pg, respectively, as described by Timbó et al (2014aTimbó et al ( , 2014b.…”

Section: Discussionsupporting

confidence: 75%

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Genomic Constitution and Relationship in Urochloa (Poaceae) Species and Hybrids

2017

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Urochloa P. Beauv. [syn. Brachiaria (Trin.) Griseb.] belongs to the family Poaceae and comprises species presenting different ploidy levels and modes of reproduction. Specific studies on genomic constitution and relationship within the genus Urochloa are limited, despite the great economic and agronomic importance of forage species and the high frequency of polyploids. Therefore, molecular cytogenetic analyses can enhance the knowledge about genomes and their differentiation, which allows making inferences about phylogenetic and genomic relationships. The current study aimed to investigate the genomic relationships between Urochloa ruziziensis (R. Germ. & Evrard) Crins (syn. Brachiaria ruziziensis Germain & Evrard.) cultivar ‘Kennedy’, Urochloa decumbens (Stapf) R. D. Webster [syn. Brachiaria decumbens (Stapf)] cultivar ‘Basilisk’, Urochloa brizantha (Hochst. ex. A. Rich.) R. D. Webster [syn. Brachiaria brizantha (A. Rich.) Stapf] cultivar ‘Marandu’, and their interspecific hybrids by means of genomic in situ hybridization, fluorescent in situ hybridization, and nuclear genome quantification by flow cytometry. We proposed the genomic constitution of U. ruziziensis, U. decumbens, and U. brizantha, such as B2B2, B1B1B2B2, and BBB1B1, respectively. Genomes B, B1, and B2 were considered to be homoeologous, but there was less affinity between genomes B and B2.

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Section: Discussionsupporting

confidence: 75%

“…Inferences were performed based on the cytometry data by Timbó et al (2014aTimbó et al ( , 2014b for the other species (U. decumbens, U. brizantha, and U. ruziziensis).…”

Section: Nuclear Dna Quantification By Flow Cytometrymentioning

confidence: 99%

Genomic Constitution and Relationship in Urochloa (Poaceae) Species and Hybrids

2017

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“…Such downsizing of genomes expressed as Cx values after polyploidization is proposed to be a general trend in angiosperms (Kellogg and Bennetzen, 2004). Similarly, Ishigaki et al (2010) and Timbó et al (2014) reported that the genome size (Cx value) of Brachiaria species decreased with increasing ploidy level, though this conclusion was reached with fewer samples than our study. Leitch and Bennett (2004) observed from a large angiosperm dataset that genome size tended to decrease with increasing ploidy levels, resulting from a loss of DNA in polyploids.…”

Section: Genome Size Variationcontrasting

confidence: 57%

“…The available literature indicates the predominance of tetraploid and a few hexaploid accessions in B. brizantha (Mendes-Bonato et al, 2002). The other species have chromosome numbers corresponding to previously published counts such as the diploid accession of B. ruziziensis, tetraploid accessions of B. brizantha and B. decumbens (Risso-Pascotto et al, 2004;Akiyama et al, 2010;Timbó et al, 2014), a tetraploid accession of B. nigropedata (Utsunomiya et al, 2005), and a hexaploid accession of B. humidicola (Boldrini et al, 2009;Akiyama et al, 2010). All chromosome numbers in the analyzed accessions were derived from x = 9 (Basappa et al, 1987).…”

Section: Issr Analysis and Data Analysismentioning

confidence: 99%

Chromosome Number, Genomic Variation, and Molecular Markers to Assess Genetic Diversity of Brachiaria Species

Nitthaisong¹,

Ishigaki

Tanaka

et al. 2016

Crop Science

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The genus Brachiaria contains approximately 100 identified species, including economically important tropical grasses; however, there is not much accessible information about the genetics or genomes of the genus. In this study, we determined the chromosome number and genome size by cytological analysis and flow cytometry, respectively, and estimated the molecular variability using intersimple sequence repeat (ISSR) markers for 28 accessions representing 11 Brachiaria species. The chromosome number of 10 species agreed with previous reports, and the chromosome number for B. xantholeuca was evaluated (2n = 4x = 36) for the first time. Genome size expressed as C values differed among these species (0.89 to 4.02 pg/2C) and increased with increasing ploidy levels. In contrast, the genome size given as a Cx value tended to decrease with increasing ploidy levels in polyploid plants. A total of 441 ISSR fragments were generated with 10 primers to assess the molecular variability of Brachiaria species. All 11 Brachiaria species clustered into three groups with the neighbor‐joining (NJ) method. We found no correlation between the clusters and the region from where the plants were collected. Nevertheless, the clustering of accessions was clearly correlated with ploidy level and reproductive mode (sexual and apomictic) except for a few accessions. Furthermore, evolution of the Brachiaria genome and genetic diversity within the genus were discussed.

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“…In Brazil, there are approximately 172 million hectares of cultivated pastures in extensive livestock farming systems (Timbó et al, 2014), ranking the country as the largest producer, consumer and exporter of forage seeds in the world (Vigna et al, 2011;Beling, 2016).…”

Section: Introductionmentioning

confidence: 99%

Harvesting methods on physical and physiological quality of Panicum maximum seeds

Machado

Cruz

Silva

et al. 2019

Rev. bras. eng. agríc. ambient.

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The quality of seeds of forage species can be influenced by the different harvesting methods used. The aim of this study was to evaluate the physical and physiological quality of seeds of Panicum maximum, cultivars 'Massai' and 'Mombaça' , obtained by the methods of ground sweeping and direct heading (cutting of the panicles) of different farmers in the year 2014. The test consisted of three lots of each cultivar from seed farmers in the state of Goiás, Brazil. The experimental design was completely randomized, in 3 x 2 factorial scheme (farmer x harvesting methods) with four replicates. The following variables were analyzed: physical purity, 1000-seed weight; germination and first count of germination. At the end of the germination the percentage of dormancy and dead seeds were evaluated by the tetrazolium test of the remaining seeds, in addition to the abnormal seedlings. The data were submitted to analysis of variance and the means of the treatments were compared by Tukey test at 0.05 probability level. Seeds of P. maximum 'Massai' and 'Mombaça' collected by ground sweeping have superior physiological quality despite the low level of purity of the lots, compared to direct heading method.Métodos de colheita na qualidade física e fisiológica de sementes de Panicum maximum RESUMO: A qualidade de sementes de espécies forrageiras pode ser influenciada pelos diferentes métodos de colheita utilizados. Nesta pesquisa objetivou-se avaliar a qualidade física e fisiológica de sementes de Panicum maximum cultivares Massai e Mombaça, obtidas pelos métodos de colheita no cacho (corte das panículas) e varredura do solo, de diferentes produtores no ano de 2014. O ensaio constituiu-se de três lotes de cada cultivar oriundas de produtores de sementes do Estado de Goiás, Brasil. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 3 x 2 (produtor x método de colheita) com quatro repetições. Foram avaliadas: pureza física, massa de mil sementes; germinação e primeira contagem de germinação. Ao final do teste foram avaliadas as porcentagens de sementes dormentes e mortas, pelo teste de tetrazólio das sementes remanescentes, além das plântulas anormais. Após a obtenção dos dados, os mesmos foram submetidos à análise de variância e as médias dos tratamentos foram comparadas pelo teste de Tukey, a 0,05 de probabilidade. As sementes de P. maximum cultivares Massai e Mombaça colhidas por varredura do solo tem melhor qualidade fisiológica, apesar do baixo nível de pureza dos lotes quando comparadas à colheita no cacho.

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Nuclear DNA content and chromosome number in Brachiaria spp. genotypes

Cited by 14 publications

References 15 publications

Genomic Constitution and Relationship in Urochloa (Poaceae) Species and Hybrids

Genomic Constitution and Relationship in Urochloa (Poaceae) Species and Hybrids

Chromosome Number, Genomic Variation, and Molecular Markers to Assess Genetic Diversity of Brachiaria Species

Harvesting methods on physical and physiological quality of Panicum maximum seeds

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