Seed of soybeans, Glycine max L. (Merrill), cultivar IAC-8 and lines A-5, low linolenic acid content, PI 408251, lacking L1 mutant, PI 86023, lacking L2 mutant, Tohoko nº 74, lacking L3 mutant, and F2 population from the crosses between IAC-8 and mutant lines (lacking L1, L2 and L3) were analysed for linolenic acid content, lipoxygenase activity and identification of mutant lines lacking L1, L2 or L3 isoenzymes. The purpose was to evaluate methods to identify mutants lines of soybean for lipoxygenase and to verify a possible correlation between enzimatic activity and linolenic acid content. The enzimatic activity was estimated quantitatively by a colorimetric method and lipoxygenase isoenzymes detection by isoelectric focusing. The oil seed content was determined by gravimetry and the fatty acids content by gas liquid chromatography of their methyl esters. The lipoxygenase activity data was good to indicate mutant lines for the final identification using isoelectric focusing. It permits the use of this method for choosing lines in breeding program to obtain a good soybean oil stability. It was not observed correlation, in the material studied, between enzymatic activity and linolenic acid content.
soybeans; Glycine max (L.) (Merrill); lipoxygenase; linolenic acid