Resumo: O objetivo deste trabalho foi identificar marcadores de polimorfismos de nucleotídeo único (SNPs) ligados a locos controladores de características quantitativas (QTLs) associados a maiores conteúdos de proteína e óleo em soja. Foram avaliadas 169 cultivares brasileiras de soja, genotipadas com 6 mil marcadores SNPs. Os conteúdos de proteína e óleo foram obtidos pelo método de refletância no infravermelho próximo. As análises de correlação e regressão linear múltipla foram utilizadas para a identificação de desequilíbrio de ligação entre os marcadores SNPs e os QTLs associados às duas características. Foram identificados sete QTLs associados ao conteúdo de proteína, em seis cromossomos (2, 6, 11, 12, 13 e 16), o que explicou 60,9% da variação nesta característica. Para o conteúdo de óleo, foram identificados oito QTLs em seis cromossomos (1, 4, 5, 6, 17 e 19), o que explicou 78,3% da variação na característica. A correlação entre o número de locos com alelos favoráveis e as características avaliadas foi de 0,49 para o conteúdo de proteína e de 0,60 para o conteúdo de óleo. Os marcadores moleculares identificados estão mapeados em regiões genômicas que contêm QTLs previamente mapeados para as duas características, o que reforça a associação dessas regiões com o controle genético dos conteúdos de óleo e proteína em soja.

Abstract: The objective of this work was to identify single-nucleotide polymorphism (SNP) markers linked with quantitative trait loci (QTLs) associated with increased contents of protein and oil in soybean. A total of 169 Brazilian soybean varieties, genotyped with 6,000 SNP markers, were evaluated. Protein and oil contents were obtained with the near-infrared reflectance method. Correlation and multiple linear regression analyses were used to identify linkage disequilibrium between SNP markers and the QTLs associated with the two characteristics. Seven QTLs were found to be associated with protein content, on six chromosomes (2, 6, 11, 12, 13, and 16), explaining 60.9% of the variation in this trait. For oil content, eight QTLs were identified on six chromosomes (1, 4, 5, 6, 17, and 19), explaining 78.3% of the variation in the trait. The correlation between the number of loci containing favorable alleles and the evaluated characteristics was 0.49 for protein content and 0.60 for oil content. The molecular markers identified are mapped in genomic regions containing QTLs previously mapped for both characteristics, which reinforces the association between these regions and the genetic control of oil and protein contents in soybean.

Wheat (Triticum aestivum) is one of the most important food staples in the south of Brazil. Understanding genetic variability among the assortment of Brazilian wheat is important for breeding. The aim of this work was to molecularly characterize the thirty-six wheat cultivars recommended for various regions of Brazil, and to assess mutual genetic distances, through the use of microsatellite markers. Twenty three polymorphic microsatellite markers (PMM) delineated all 36 of the samples, revealing a total of 74 simple sequence repeat (SSR) alleles, i.e. an average of 3.2 alleles per locus. Polymorphic information content (PIC value) calculated to assess the informativeness of each marker ranged from 0.20 to 0.79, with a mean of 0.49. Genetic distances among the 36 cultivars ranged from 0.10 (between cultivars Ocepar 18 and BRS 207) to 0.88 (between cultivars CD 101 and Fudancep 46), the mean distance being 0.48. Twelve groups were obtained by using the unweighted pair-group method with arithmetic means analysis (UPGMA), and thirteen through the Tocher method. Both methods produced similar clusters, with one to thirteen cultivars per group. The results indicate that these tools may be used to protect intellectual property and for breeding and selection programs.