Protein, lipid and isoflavone contents of food-type soybean lines at two sowing dates / Teores de proteína, óleo e isoflavonas de linhagens de soja tipo alimento em duas épocas de semeadura

Few works have reported the relationship among genotype, temperature, rainfall and the chemical compounds of soybean. Therefore, the aim of this study was to investigate the interaction effect between soybean food-type inbred lines sowed in two different dates and the contents of protein, oil and isoflavones. Eight lines with null lipoxygenase seeds classified as food-type soybean were sowed in October 7 (early sowing) and October 29 (late sowing) at 2013/2014 crop year. The oil, protein and isoflavones contents were determined and the data were analyzed by variance analysis (ANOVA), principal component analysis (PCA) and UPGMA hierarchical. The genetic variability, sowing date and interactions between inbred lines and sowing date showed differences for all characteristics, except for oil content that did not showed a significant effect to the interaction. The greater participation of complex interaction was attributed to protein content with 87.82 %. According to PCA and UPGMA results, the food-type soybean lines were separated into three groups and were consistent in both sowing dates. The UEL 131 and UEL 153 lines showed the highest isoflavones content for the two sowing dates, indicating these genotypes as promising for breeding programs.

Poucos trabalhos relataram a relação entre genótipo, temperatura, precipitação e os compostos químicos de grãos de soja. Portanto, o objetivo deste estudo foi investigar o efeito da interação entre linhagens de soja tipo alimento semeadas em duas épocas nos teores de proteína, óleo e isoflavonas nos grãos. Oito linhagens de soja ausentes das enzimas lipoxigenases e classificadas como tipo alimento foram semeadas em 7 de outubro (semeadura precoce) e 29 de outubro (semeadura tardia) no ano agrícola 2013/2014. Os conteúdos de óleo, proteína e isoflavonas foram determinados e os dados foram submetidos a análise de variância (ANAVA), análise de componentes principais (PCA) e UPGMA hierárquica. A variabilidade genética, a época de semeadura e as interações entre linhagens e a época de semeadura mostraram diferenças para todas as características, com exceção do teor de óleo que não apresentou efeito significativo na interação. A maior participação da interação complexa foi atribuída ao teor de proteína com 87,82%. De acordo com os resultados da PCA e UPGMA, as linhagens de soja tipo alimento foram separadas em três grupos que se mantiveram com a mudança da época de semeadura. As linhagens UEL 131 e UEL 153 mostraram o maior teor de isoflavonas em ambas as épocas de semeadura, indicando que esses genótipos são promissores para programas de melhoramento.

New soybean (Glycine max Fabales, Fabaceae) sources of qualitative genetic resistance to Asian soybean rust caused by Phakopsora pachyrhizi (Uredinales, Phakopsoraceae)

Asian soybean rust (ASR), caused by the phytopathogenic fungi Phakopsora pachyrhizi, has caused large reductions in soybean (Glycine max) yield in most locations in Brazil where it has occurred since it was first reported in May 2001. Primary efforts to combat the disease involve the development of resistant cultivars, and four dominant major genes (Rpp1, Rpp2, Rpp3 and Rpp4) controlling resistance to ASR have been reported in the literature. To develop new long-lasting soybean ASR resistance genes, we used field experiments to assess ASR leaf lesion type in 11 soybean genotypes (BR01-18437, BRS 184, BRS 231, BRS 232, BRSGO Chapadões, DM 339, Embrapa 48, PI 200487, PI 230970, PI 459025-A and PI 200526) and the 55 F2 generations derived from their biparental diallel crosses. The results indicated that PI 200487 and PI 200526 carry different dominant resistance major genes which are both different from Rpp2 through Rpp4. Furthermore, resistance to ASR in BR01-18437 is controlled by a single recessive major gene, also different from Rpp1 through Rpp4 and different from the genes in PI 200487 and PI 200526.