Gamma-ray induction of a mutant soybean [Glycine max (L.) Merrill] line lacking all seed lipoxygenases

Induction of a soybean line lacking all isozymes of seed lipoxygenase was attempted using γ-radiation and of 1,813 seeds in M3 generation, only one was identified as a seed lacking all the isozymes by SDS-PAGE. This line did not present any physiological abnormality over 10 generations or more (M4-M14) and no significant influence of the enzyme on the agricultural traits was observed during the performance test in fields. In the resistance test against insect pests, significant differences were not found among the varieties and the lines tested. These results suggest that deletion of all lipoxygenase isozymes would not affect the soybean production in practice. The lipoxygenase activity was not detected in the leaves as well as the seeds of this line, suggesting that this enzyme are not indispensable for the soybean growth. The validity of this line in food processing fields was examined through determining the levels of hexanal production and DETBA. This line was found able to improve the taste of soybean cookies and use in combination with other materials as flour, egg, etc. because the line has no lipoxygenase activity. (M.N.)