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Soybean oil is one of the most important vegetable oils in world. Increasing oil content and improve its composition is an important aim of many soybean breeding programs. In this context, the objective of this study was to identify QTLs controlling oil and fatty acid contents in soybean seed in different locations. For this, we developed F2-derived populations by crossing CS303TNKCA and FA22 lines, and analyzed oil and fatty acid content in four locations in Brazil. We evaluated the correlations of traits in each location and between locations and used 1536 SNPs to molecular characterize this population. QTLs associated with the average values of four environments were identified by using simple interval mapping. A linkage map was generated using 534 SNP markers, and 25 linkage groups were formed. A total of 20 QTLs controlling oil, palmitic, stearic, oleic, linoleic and linolenic contents were found, varying from one (linolenic content) to six (palmitic content), and explaining from 7.02% (qSte-13) to 70.37% (qLin-14) of phenotypic variation. We could not associate eight QTLs (qPal-02, qOle-02, qLol-02, qOle-04, qLol-04, qPal-13.2, qSte-15 and qSte-17) with reported QTLs and genes, so these could be set as new QTLs controlling fatty acid composition. The results found in the present work can help understand the genetic basis of these traits and help breeders to modify oil content and composition in soybean seed, especially in tropical conditions.

We molecularly characterized a new mutation in the GmFAD3A gene associated with low linolenic content in the Brazilian soybean cultivar CS303TNKCA and developed a molecular marker to select this mutation. Soybean is one of the most important crops cultivated worldwide. Soybean oil has 13% palmitic acid, 4% stearic acid, 20% oleic acid, 55% linoleic acid and 8% linolenic acid. Breeding programs are developing varieties with high oleic and low polyunsaturated fatty acids (linoleic and linolenic) to improve the oil oxidative stability and make the varieties more attractive for the soy industry. The main goal of this study was to characterize the low linoleic acid trait in CS303TNKCA cultivar. We sequenced CS303TNKCA GmFAD3A, GmFAD3B and GmFAD3C genes and identified an adenine point deletion in the GmFAD3A exon 5 (delA). This alteration creates a premature stop codon, leading to a truncated protein with just 207 residues that result in a non-functional enzyme. Analysis of enzymatic activity by heterologous expression in yeast support delA as the cause of low linolenic acid content in CS303TNKCA. Thus, we developed a TaqMan genotyping assay to associate delA with low linolenic acid content in segregating populations. Lines homozygous for delA had a linolenic acid content of 3.3 to 4.4%, and the variation at this locus accounted for 50.83 to 73.70% of the phenotypic variation. This molecular marker is a new tool to introgress the low linolenic acid trait into elite soybean cultivars and can be used to combine with high oleic trait markers to produce soybean with enhanced economic value. The advantage of using CS303TNKCA compared to other lines available in the literature is that this cultivar has good agronomic characteristics and is adapted to Brazilian conditions.

The macaw palm, Acrocomia aculeata (Jacq.) Lodd. ex Mart., is a Brazilian native species with great potential for biofuel production. The aim of this work was to analyze macaw palm genetic diversity to structure and assist in the definition of sampling strategies for germplasm banks. Forty-six microsatellite markers, from which seven polymorphic markers were used to evaluate 103 macaw palm individuals collected from different Brazilian locations. The polymorphic markers were used to generate a dissimilarity matrix by weighted index. The imaging of genetic variability was realized by 3D projection of matrix dissimilarity. Sixty-seven individuals had their ITS region sequenced and aligned, and the mutations found were used to generate a haplotype network. The average genetic distance identified between individuals was 76.2%, ranging from 3.7 to 100%. Genetic variability structure was not found. ITS region sequencing of the 67 individuals revealed four polymorphic sites, defining four haplotypes. The results of this study suggest that historically, macaw populations were strongly connected, indicating a recent population expansion of the species. The results indicate that macaw genetic variety sampling should focus on effective collection in selected locations. Areas such as Caatinga and Humid Chaco however, could present new sources of genetic variability, and should be studied. RESUMO A macaúba, Acrocomia aculeata (Jacq.) Lodd. ex Mart.), é uma das espécies nativas brasileiras com maior potencial para a produção de biocombustíveis. O objetivo deste trabalho foi analisar a diversidade e estruturação genética de macaúba para auxiliar na definição de estratégias de amostragem para bancos de germoplasma. Quarenta e seis marcadores microssatélites, dos quais sete marcadores polimórficos foram utilizados para avaliar 103 indivíduos de macaúba coletados em diferentes regiões do Brasil. Os marcadores polimórficos foram utilizados para gerar uma matriz de dissimilaridade pelo índice ponderado. A visualização da variabilidade genética foi realizada através de uma projeção 3D da matriz de dissimilaridade. Sessenta e sete destes indivíduos tiveram sua região ITS sequenciada e alinhada, e as mutações encontradas foram utilizadas para gerar uma rede de haplótipos. A distância genética média identificada entre os indivíduos foi de 76,2%, variando de 3,7 a 100%. Não foi encontrada estruturação da variabilidade genética. O sequenciamento da região ITS dos 67 indivíduos revelou quatro sítios polimórficos, definindo quatro haplótipos. Os resultados obtidos neste estudo sugerem que as populações de macaúba estiveram fortemente conectadas historicamente, indicando recente expansão populacional da espécie. Os resultados indicam que a amostragem da variabilidade genética de macaúba deve estar focada em coletas mais robustas em poucos locais, mas áreas como Caatinga e Chaco Úmido podem apresentar novas fontes de variabilidade genética, e devem ser melhor estudadas.