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Inheritance of Seed Isoflavone Contents in Soybean Cultivars Shinpaldalkong2 and Hwangeumkong

JaHwan Ku1, Jung-Kyung Moon, Hong-Tae Yun, Keum-Yong Park, YeongHo Lee, Moon Tae Song, HanSun Hur and SeongHo Choi

1 National Institute of Crop Science, Email


Soy products contain isoflavones (genistein, daidzein, and glycitein) that display biological effects when ingested by humans and animals. Therefore, the content and quality of isoflavones in soybean is a key to their biological effect. The objective of the present study was to understand inheritance of isoflavone content in soybean seeds. The study used F2 and F3 lines developed from the cross of ‘Shinpaldalkong2’ and ‘Hwangeumkong’, two cultivars that contrast for isoflavone content. Seed isoflavone content of each lines was determined by high performance liquid chromatography (HPLC). The distribution of isoflavone content was continuous and unimodal. Narrow-sense heritability estimates with high content selection were 67% for total isoflavone, 80% for daidzein, 57% for genistein, and 79% for glycitein. Heritability estimates for low content selection were 30% for total isoflavone, 37% for daidzein, 27% for genistein, and 42% for glycitein.

Media summary

Understanding inheritance of isoflavone content and composition will result in development of value added soybeans.

Key Words

Heritability, isoflavone, daidzein, genistein, glycitein, soybean


Soybean products contain a plethora of bioactive phytochemicals (e.g., isoflavones, saponins, phytic acids, phytosterols, trypsin inhibitors, phenolic acids, and peptides. Moreover, soybean contains plant estrogens commonly called phytoestrogens or more specifically isoflavones. The three major groups of isoflavones found in soybeans are genistein, daidzein, and glycitein. The numerous health benefits of soy phytoestrogens appear to be expanding. Soy phytoestrogens are being implicated in reduceding risk of breast and prostate cancer, cardiovascular disease, and osteoporosis (Messina and Barnes 1991; Cassdy et al. 1994; Anderson et al. 1995; Anthony et al.1996; Banz et al. 1999). The amount of isoflavones in soybean seed can vary five-fold (Eldridge and Kwolek 1983). Isoflavone content and profile can vary with year, environment, and genotype. The purpose of this study was to determine the inheritance of daidzein, genistein, and glycitein content in soybean seed. This genetic information would be useful in breeding programs aimed at developing a soybean variety that has a high and consistent concentration of a beneficial isoflavone.


The study involved 123 F2 plants and their progeny from a cross between Shinpaldalkong2 and Hwangeumkong; two soybean cultivars contrasting for isoflavone content (So 2001). The F2 seeds were sown in 2001, and F3 seeds sown in 2002 at the National Institute of Crop Science, Suwon city, Republic of Korea. The selection intensity for high content was 7.3% for the ten F2 plants selected. The selection intensity of the low content was 6.6% for the nine F2 plants were selected. Seeds were harvested from each plant, cleaned, and stored at 12% (w/w) moisture content. The seeds for each plant were harvested and analyzed separately. The isoflavone content of each sample was analyzed by HPLC analysis as described by Wang and Murphy (1994).


The frequency distributions of the F2 population for total isoflavone contents shows no significant depature from normality (P>0.05) (Figure 1). The distribution of daidzein content was peaked and skewed toward Hwangeumkong but did not significantly depart from normality (P>0.05). The distribution of genistein or glycitein content were skewed toward Shinpaldalkong2, however this distribution did not significantly depart from normality (P > 0.05). All distributions were continuous and uni-modal. There was evidence for transgressive segregation for each isoflavone and total isoflavone content. The breeding lines showed transgressive segregation for high glycitein contents and for both low and high daidzein or genistein content. Realized heritability of isoflavone by high content selection were 67% for total, 80% for daidzein, 57% for genistein, and 79% for glycitein (Table 1). Realized heritability by low content selection were 30% for total, 37% for daidzein, 25% for genistein, and 42% for glycitein.

Hwangeumkong Shinpaldalkong2

Hwangeumkong Shinpaldalkong2

Figure 1. Frequency distribution for total isoflavone, daidzein, genistein, and glycitein in F2 plants of Shinpaldalkong2/Hwangeumkong.

Table 1. Realized heritability of isoflavone content in F2 and their F3 progeny.


High content

Low content



































i : Selection differential. ΔG : Genetic advance. h2R : Realized heritability.


The high realized heritability for specific soybean isoflavones suggests that both isoflavone content and composition can be manipulated in soybean. Specific isoflavone profile may confer different results depending on the target population, so reducing unwanted isoflavones while enhancing beneficial isoflavones could be a key breeding target. Manipulation of isoflavone contents and profiles will result in the creation of special purpose value added soybeans.


Anderson JW, Jhonstone BM, Cook-Newell MA. 1995. Meta-analysis of the effect of soy protein intake on serum lipids. N Engl J med. 333:276-282.

Anthony MS, Clarkson TB. Hughes CL Jr, Morgan TM, Burke GL. 1996. Soybean isoflavones improve cardiovascular risk factors without affecting the reproductive system of peripubertal rhesus monkeys. J nutr. 126:43-50.

Banz WJ, Williams MP, Lightfoot DA, Winters TA. 1999. The effects of soy protein and soy phytoestrogens on symptoms associated with cardiovascular disease in rats. J Med Food 2: 168-170.

Cassdy A, Bingham S, Setchell K. 1994. Biological effects of a diet of soy protein rich in isoflavones on the menstrual cycle of premenopausal women. Am J Clin Nutr. 60:333-340.

Eldridge CE, Kwolek WF. 1983. Soybean isoflavones : Effects of the environment and variety on the composition. J Agric Food Chem. 31:394-396.

Messina M, Barnes S. 1991. The role of soy products in reducing risk of cancer. J Natl Cancer Inst. 17:541-546.

So EH, Ku JH, Park KY, Lee YH. 2001. Varietal difference of isoflavone content and antioxidant activity in soybean. Korean J. Breed. 33(1):35-39.

Wang H, Murphy PA. 1994. Isoflavone composition of America and Japanese soybeans in Iowa: Effects of variety, crop year and location. J Agric Chem. 42:1674-1677.

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