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With 2 figures and 2 tables Abstract An extraction and detection method was reported for fat- and water-soluble components in primary soybean seed. The HPLC retention times were 10 min for lutein, 23 min for δ-tocopherol, 27 min for γ-tocopherol, 30 min for α-tocopherol, 33 min for α-carotene and 39 min for β-carotene. The retention times of the isoflavones were 7 min for daidzin, 11 min for genistin, 15 min for malonyldaidzin and 20 min for malonylgenistin. Linear regression and two-way anova analysis were performed, and the test results indicated that there was a significant correlation (r2 = 0.9973, P 0.05) between the traditional method and the proposed method. Moreover, the strain ‘07–27’, which has high α-tocopherol and isoflavone contents in the F2 : 3 lines (F2-derived lines in F3), was screened and then crossed between a high-isoflavone soybean variety, ‘Toiku 241’, and a high-α-tocopherol soybean variety, ‘Keszthelyi A.S.’ (pollen parent). The contents of α-tocopherol and total isoflavones were 8.91 and 622.96 mg/100 g DW, respectively.

Cadmium (Cd) is a pollutant heavy metal that is naturally present in soils and highly toxic to biological organism even at low concentrations. Significant differences were observed among soybean [Glycine max (L.) Merr.] cultivars in the uptake of Cd by root and its posterior translocation to the shoot and grain. The aim of this research was to identify quantitative trait loci (QTLs) for seed Cd concentration in soybean. A single population derived from a cross between the cultivars Harosoy and Fukuyutaka, which differ in seed Cd levels, were used for QTL analysis. The population consisted of 93 F 5:6 recombinant inbred lines (RILs), 93 F 6:7 RILs, 93 F 7:8 RILs, and 100 F 6:7 near-isogenic lines (NILs). A total of 220 simple sequence repeat (SSR) markers were genetically mapped on the 93 F 5:6 RILs population and clustered into 22 molecular linkage groups (MLGs) which covered a genetic distance of approximately 2400 centimorgans (cM). Analysis revealed one major QTL (cd1) on Chromosome 9 (MLG K) associated with seed Cd concentration. The cd1 was stable across years-generations and accounted for 82, 57, and 75% of the genetic variation in the RILs populations tested in the field. Effect of cd1 was verified by means of a NIL population developed from the F 5:6 RILs. The followup survey results indicated that the novel SSR markers Gm09: 4770663 and Gm09: 4790483 assigned to MLG K seemed to be suitable markers for selecting genotypes with low seed Cd concentration in soybean.

We performed genetic analysis of lutein content using three progeny populations from crosses between soybean variety and wild soybean strains with high lutein content. A few F2 seeds derived from a soybean line, Toiku241 × a wild accession, B09092 showed almost equal lutein content to that of the wild soybean parent, B09092. The high values of the broad-sense heritability estimated in F2 seed generations and the highly positive correlation between the two generations of RILs from a soybean line, TK780 × a wild accession, B01167, indicated that lutein content is a heritable trait. There was no significant correlation between lutein content and seed weight in F3 seeds from cv. Toyomusume × a wild accession, GD50344. Flowering time was positively correlated with lutein content in the three populations. We identified xanthophylls, such as neoxanthin, violaxanthin and antheraxanthin, in addition to the major lutein in wild soybean strains. Xanthophyll content in progeny populations from interspecific crosses showed highly positive correlations with lutein content, suggesting that the high lutein trait of the wild soybean might be implicated in the biosynthesis and/or accumulation of xanthophylls during seed filling.

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 α-tocopherol (α-Toc) and lutein are relatively low in the seeds. Therefore, genetic manipulation to enhance the α-Toc and lutein contents is an important breeding objective in soybean. Recently, we have successfully identified soybean varieties and wild strains with high α-Toc and lutein contents, respectively. In the present investigation, we made a cross between a soybean variety with a high α-Toc content thereafter referred to as a high α-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 α-Toc and lutein contents of the F2 seed and F2-plant (F3 seeds) populations by a single-pass method for extraction and quantification, using high performance liquid chromatography (HPLC). The α-Toc content of the F2 seeds ranged from 1.0 to 6.0 mg/100 g meal, whereas that of the high α-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 F2 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 α-Toc and lutein contents in the F2 seeds was estimated to be 0.598 and 0.656, respectively. In the F2-plants (F3 seeds), the broad-sense heritabilities were 0.693 for the α-Toc content and 0.824 for the lutein content, respectively. The heritabilities in a narrow sense for the α-Toc and lutein contents in the F2 seeds were 0.598 and 0.413, respectively. In the F2-plants (F3 seeds), the estimates were 0.693 and 0.718, respectively. The results suggested that both high α-Toc and lutein contents are highly heritable. A significant positive correlation was observed between the α-Toc and lutein contents both in the F2 seeds (r = 0.420, P < 0.01) and in the F2-plants (F3 seeds) (r = 0.228, P < 0.01). In addition, a significant positive genetic correlation was observed between the α-Toc and lutein traits in the F2-plants (F3 seeds) (rG = 0.311, P < 0.01). No correlation was observed between the 100-kernel weight and lutein content in the F2-plants (F3 seeds). Likewise no correlation was obtained between the 100-kernel weight and α-Toc content. These results indicate that it is possible to simultaneously select individuals among the progenies with high contents of lutein and α-Toc without decreasing the kernel weight of the seeds.