Nuclear DNA content and chromosome number in Brachiaria spp. genotypes
Nuclear DNA content and chromosome number in Brachiaria spp. genotypes
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DOI：
10.1590/s1806-66902014000100008
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发表时间：
2014-03-01
期刊：
影响因子：
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通讯作者：
Davide, Lisete Chamma
中科院分区：
文献类型：
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作者：
Timbó, Ana Luiza de Oliveira;Pereira, Roselaine Cristina;Davide, Lisete Chamma
臂形草育种方案。在有性和无融合生殖植物之间进行种内和种间杂交，以获得具有所需特性的新品种。由于该属种内和种间存在不同的倍性水平，因此有必要评估育种计划中使用的基因型，作为育种者采用杂交策略的指导。本工作通过对臂形草属植物DNA含量和染色体数目的测定，探讨臂形草属植物的倍性水平。基因型在15个基因型中，DNA含量随倍性水平（2x、3x和4x）的不同而不同，在种和/或分类单元之间也存在差异，B的平均DNA含量为1.74 pg（2x）。ruziziensis，3.74 pg（4x），在B中。对于B为3.52 pg（4x）。布里赞塔。对于基因型86，获得2.57pg的DNA，并且2n = 3x = 27，表明三倍体加入，可能是天然杂种。总DNA含量的变化允许将四倍体物种Brachiaria Brizantha和Brachiaria decumbens（2n = 4x = 36）与Brachiaria ruziziensis（2n = 2x = 18）区分开来，以及这些物种的可能的杂交三倍体（2n = 3x = 18）。
Breeding programs for Brachiaria spp. use both intraspecies and interspecies crosses between sexual and apomictic plants in order to obtain new cultivars with the desired characteristics. As there are different ploidy levels both within and between species of this genus, it becomes necessary to evaluate the genotypes used in breeding programs, as a guide to breeders when adopting crossing strategies. In this work, DNA content and chromosome number were determined in order to characterise ploidy levels in Brachiaria spp. genotypes. In the analysis of 15 genotypes, DNA content varied with the ploidy levels (2x, 3x and 4x), and between species and/or taxon. The average DNA content was 1.74 pg (2x) in B. ruziziensis, 3.74 pg (4x) in B. decumbens and 3.52 pg (4x) for B. brizantha. For the genotype 86, 2.57 pg of DNA was obtained and 2n = 3x = 27, indicating a triploid accession, probably a natural hybrid. The variation in the total DNA content allowed the differentiation of Brachiaria ruziziensis (2n = 2x = 18) from the tetraploid species Brachiaria Brizantha and Brachiaria decumbens (2n = 4x = 36), as well as the probable hybrid triploid (2n = 3x = 18) of these species.