2014-07-292012-09-062011-04-26RIBEIRO, Keyla de Oliveira. Characterization of soybean germplasm for protein, oil and fatty acids contents. 2011. 153 f. Tese (Doutorado em Ciências Agrárias) - Universidade Federal de Goiás, Goiânia, 2011.http://repositorio.bc.ufg.br/tede/handle/tde/448Soybean is currently the most prominent crop in the Brazilian production of grains. Its main products include oil and meal, which have been used for the production of food and animal feed. The high protein contents represent the main attraction of soybean use in diet. Furthermore, soybean oil has also been used in the production of biodiesel. These industrial segments demands cultivars with similar profiles of fatty acids, in which case the oil guarantees a better oxidative stability. This profile corresponds to oils with low polyunsaturated acids contents, associated to high contents of monounsaturated fatty acids. For that, it becomes essential the chemical characterization of grains in cultivars, which could be extended to the genetic resources preserved in germplasm collections, with the purpose of breeding soybean in these traits. Nowadays the characterization of these resources is still deficient, mainly regarding special traits such as those previously mentioned. In this context, the objective of this study was to characterize a sub-collection of 527 accessions of soybean from the germplasm bank of Secretaria de Agricultura, Pecuária e Abastecimento do Estado Goiás (SEAGRO-GO), based on the physicochemical traits of the grain, including protein and oil contents in the meal, and the main fatty acids contents of the oil. The grains were obtained through a field trial carried out at the experimental unit of SEAGRO-GO (16°43 S; 49°7 W; 765 m), county of Senador Canedo - GO, in the 2007-2008 growing season. The experimental design was augmented blocks (blocks of Federer), with two check cultivars (Conquista and Monsoy 6101). The plots were constituted by one row of plants (5.0 m x 0.5 m). The protein contents were quantified by the Kjeldahl method, the oil by the Soxhlet method, and the fatty acids (palmitic, stearic, oleic, linoleic and linolenic) by FAME method (Fatty Acid Methyl Esters). To assess the genetic divergence among accessions the multivariate analyses used were: canonical variables, principal components and cluster analysis. The last one was performed by the hierarchical clustering method using UPGMA criteria. Canonical discriminant analysis was also performed on established similarity groups and on maturity groups of the accessions (early, intermediate and late). In the principal components analysis it was needed three components to retain 78% of the total variance, whereas in the canonical variables analysis only two of these variables captured 81.2% of this variation. About the phenotypic variation, it was observed that the studied sub-collection presents a relatively lowl variability among its accessions, in protein content (from 35.7% to 44.0%) and oil content (from 14.8% to 18.5%). For fatty acids, the germplasm showed a relatively wide variation, although characteristics of industrial interest such as high contents of oleic acid (greater than 40%) and low contents of polyunsaturated acids (less than 40%) are restricted to few accessions. Regarding the polyunsaturated acids, the germplasm presents satisfactory variability to the linoleic oil (omega-6), however, low variability to the linolenic acid (omega-3), especially in its upper limit. By cluster analysis they were established five similarity groups (A, B, C, D, and E) with the formation of subgroups in some them. The accessions of groups A and B present the largest oil and protein contents, respectively. The accessions of group C outstood with the best profile of oil quality (oxidative stability), and they were followed by the accessions of E and B groups. Among the germplasm with the best profiles of oil oxidative stability, it was still possible to identify in this collection five divergent groups of accessions with significant differences in fatty acids contents. The polyunsaturated and saturated fatty acids are the most relevant variables in the structuring of genetic diversity of this germplasm.application/pdfAcesso Abertodivergência genéticavariável canônicaestabilidade oxidativadivergencecanonical variableoxidative stabilityCNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETALTese