CONICET | Buscador de Institutos y Recursos Humanos

Soybean seed is a product of central importance in the agro-economy of Argentina, so it is necessary to attend its quality by generating strategies in order to obtain improved genotypes. The soybean seed derivatives mainly marketed are protein flour and oil, which are used for human and animal feeding and biofuel industry. In this work, a characterization of the organic composition of soybean cultivars selected from 1100 F7 lines belonging to 9 segregating populations is presented. This subsample comes from crossings between the high-performance commercial genotype DM3100 and high-protein concentration parental with large (PI538376) or small (PI818757) seed size. The content of reserves and chlorophyll in the grains were evaluated in samples from plants at different phenological states, which corresponded to four different values of grain moisture: 74, 66, 46 and 9%. Gravimetric analyzes revealed that the dry grains (9% moisture) contained a range of 15-22% of lipids depending on the genotype. In addition, the proteins accounted for between 36 and 44% of the final weight of mature soybean seeds, according to the Kjeldahl method. A negative correlation and a temporary offset in the accumulation of the different components were observed, while oil deposited at the end of the filling, the proteins accumulated earlier. On the other hand, the levels of chlorophyll decreased as maturation progressed in accordance with the decrease in the light that reached the growing embryos. These results allowed the selection of pairs of soybean isogenic lines contrasting in terms of protein and oil content. This work constitutes a starting point in order to detect metabolic differences that explain the different level of reserve compounds and will help us identify molecular components involved in oil and/or protein biosynthesis, including enzymes, transporters, transcription factors and other proteins.