Genetic diversity of sweet sorghum germplasm in Mexico using AFLP and SSR markers

Abstract

-The objective of this work was to evaluate the diversity and genetic relationships between lines and varieties of the sweet sorghum (Sorghum bicolor) germplasm bank of the National Institute for Forestry, Agriculture and Livestock Research, Mexico, using AFLP and SSR markers. The molecular markers revealed robust amplification profiles and were able to differentiate the 41 genotypes of sweet sorghum evaluated. Analysis of the frequency and distribution of polymorphic fragments allowed for the detection of unique (AFLP) and rare (SSR) alleles in several genotypes , indicating that these markers may be associated with a feature that has not yet been determined or may be useful for the identification of these genotypes. The genetic relationships indicated the presence of at least two types of sweet sorghum: a group of modern genotypes used for sugar and biofuel production, and another group consisting of historic and modern genotypes used for the production of syrups. Sweet sorghum genotypes may be used to develop new varieties with higher sugar and juice contents.Index terms: Sorghum bicolor, biofuels, genetic improvement, molecular marker, rare allele. Diversidade genética em germoplasma de sorgo sacarino no México com uso de marcadores AFLP e SSRResumo -O objetivo deste trabalho foi avaliar a diversidade e as relações genéticas entre linhagens e variedades de sorgo sacarino (Sorghum bicolor) do banco de germoplasma do Instituto Nacional de Investigações Florestais, Agrícolas e Pecuárias, México, por meio de marcadores AFLP e SSR. Os marcadores moleculares revelaram robustez dos perfis de amplificação e permitiram diferenciar os 41 genótipos de sorgo sacarino avaliados. A análise da frequência e da distribuição dos fragmentos polimórficos permitiu detectar alelos únicos (AFLP) e raros (SSR) em diversos genótipos (RBSS-8, RBSS-9, RBSS-25, RBSS-32 e RBSS-37), o que indica que estes marcadores podem estar associados a uma característica que ainda não foi determinada ou podem ser úteis para a identificação destes genótipos. As relações genéticas indicaram a presença de pelo menos dois tipos de sorgo sacarino: um grupo de genótipos modernos usados para a produção de açúcar e biocombustíveis, e outro grupo formado por genótipos antigos e modernos utilizados para a produção de xaropes. Genótipos de sorgo sacarino podem ser usados para o desenvolvimento de novas variedades com maior conteúdo de açúcar e caldo.Termos para indexação: Sorghum bicolor, biocombustíveis, melhoramento genético, marcador molecular, alelos raros.

Suitability of target region amplified polymorphism (TRAP) markers to discern genetic variability in sweet sorghum

“…The PIC measures the discriminatory power of a marker system where the theoretical maximum PIC value for a dominant marker is 0.5 [ 34 ]. An average PIC value of 0.32 found in the present study is also in agreement with the value found in sweet sorghum using AFLP markers [ 17 ] and in grain sorghum using SSR markers [ 45 ]. These results depicting the fact that TRAP markers can be used as a useful tool to study genetic variability in sweet sorghum.…”

“…An array of marker systems, including randomly amplified polymorphic DNA (RAPD) [14,15], amplified fragment length polymorphism (AFLP) [16,17], inter simple sequence repeats (ISSR) [15], simple sequence repeats (SSR) [17][18][19][20][21], and single nucleotide polymorphisms (SNP) [18,22] markers have been used to study patterns of genetic diversity and relationship among sweet sorghum accessions and breeding lines. Markers that are designed to measure genetic diversity for target-specific breeding purposes should be based on functionally characterized genes since they may reflect functional polymorphisms [23].…”

Sweet sorghum as biofuel feedstock: recent advances and available resources

“…Despite having diverse origin, sweet sorghum lines could be distinguished into separate groups based on usage (biofuel or syrup) through genetic markers. Using AFLP and SSR markers, Pecina-Quintero et al [ 101 ] grouped six sweet sorghum lines into two distinct groups based upon their uses. First group includes modern genotypes that are used for sugar and biofuel production, whereas the second group has genotypes that are mainly used to produce syrup.…”

Regulation of assimilate import into sink organs: update on molecular drivers of sink strength

“…Additionally, Murray et al (2009) used both SSR and single nucleotide polymorphism (SNP) markers to genotype 125 cultivars of sorghum, and classified the sweet sorghum varieties into three major groups based on differing stem sugar contents. Similarly, using amplified fragment length polymorphism (AFLP) and SSR markers, two types of sweet sorghum with different brix content (a measure of the level of solutes in stem juice) were detected in a germplasm collection in Mexico (Pecina-Quintero et al, 2012). Likewise, differences were observed in sugar composition and content from eight sugarcane varieties, including four commercial cultivars (Tai and Miller, 2002).…”