Simultaneous accumulation of high contents of alpha-tocopherol and lutein is possible in seeds of soybean (Glycine max (L.) Merr.)

Soybean is rich in various functional components such as isoflavones, saponins, tocopherols and sterols that are beneficial to human health. However, the contents of some of these components such as alpha-tocopherol (alpha-Toc) and lutein are relatively low in the seeds. Therefore, genetic manipulation to enhance the alpha-Toc and lutein contents is an important breeding objective in soybean. Recently, we have successfully identified soybean varieties and wild strains with high alpha-Toc and lutein contents, respectively. In the present investigation, we made a cross between a soybean variety with a high alpha-Toc content thereafter referred to as a high alpha-Toc soybean variety, Keszthelyi A.S. (female parent), and a wild soybean strain with a high lutein content thereafter referred to as a high lutein wild soybean strain, B09092 (pollen parent). We analyzed the alpha-Toc and lutein contents of the Fsub(2) seed and Fsub(2)-plant (Fsub(3) seeds) populations by a single-pass method for extraction and quantification, using high performance liquid chromatography (HPLC). The alpha-Toc content of the Fsub(2) seeds ranged from 1.0 to 6.0 mg/100 g meal, whereas that of the high alpha-Toc parent, var. Keszthelyi A.S. varied from 4.27 to 6.43 mg/100 g meal, and that of the wild soybean parent, B09092 ranged from 1.74 to 2.30 mg/100 g meal. The lutein content of the Fsub(2) seeds ranged from 0.1 to 4.0 mg/100 g meal, while that of the var. Keszthelyi A.S. from 0.19 to 0.42 mg/100 g meal, and that of the high lutein parent, B09092 from 2.48 to 3.50 mg/100 g meal. Broad-sense heritability for the alpha-Toc and lutein contents in the Fsub(2) seeds was estimated to be 0.598 and 0.656, respectively. In the Fsub(2)-plants (Fsub(3) seeds), the broad-sense heritabilities were 0.693 for the alpha-Toc content and 0.824 for the lutein content, respectively. The heritabilities in a narrow sense for the alpha-Toc and lutein Contents in the Fsub(2) seeds were 0.598 and 0.413, respectively. In the Fsub(2)-plants (Fsub(3) seeds), the estimates were 0.693 and 0.718, respectively. The results suggested that both high alpha-Toc and lutein contents are highly heritable. A significant positive correlation was observed between the alpha-Toc and lutein contents both in the Fsub(2) seeds (r=0.420, P0.01) and in the Fsub(2)-plants (Fsub(3) seeds) (r