A new soybean [Glycine max (L.) Merr.] cultivar, ‘Dadrim,’ was developed by the National Institute of Crop and Food Science (NICS). ‘Dadrim’ is characterized by its superior suitability for tofu processing and high adaptability to mechanized cultivation. This cultivar ‘Milyang374’ was developed using the pedigree method from an artificial cross made in 2012 between ‘Milyang231’ and ‘Chamol.’ Its agronomic characteristics and production stability were verified through regional adaptation trials conducted over three years (2020- 2022). ‘Dadrim’ exhibits a determinate growth habit, white flowers, and spherical seeds with a yellow seed coat and yellow hilum. It is a large-seeded variety with a 100-seed weight of 30.9 g. As a late-maturing variety, it reaches maturity around October 22. Despite a relatively short plant height, it features a high first pod height of 16 cm, making it advantageous for mechanical harvesting. ‘Dadrim’ is resistant to bacterial pustule and soybean mosaic virus and possesses excellent lodging resistance. Notably, ‘Dadrim’ demonstrates a high tofu yield of 283%, which is 67% points higher than ‘Daewonkong’. The resulting tofu has a soft texture, making it suitable for soft and silken tofu. It also received high preference scores for taste and texture in sensory evaluations. ‘Dadrim’ yielded 3.37 tons/ha, an 8% increase compared to ‘Daewonkong.’ This new variety is expected to increase farm income and advance the domestic tofu industry (Registration No. 10461).

Tofu, a widely consumed soy-based product, has seen increasing consumer demand, driven by health and dietary trends. Enhancing the processing suitability of soybeans requires analysis of the genetics associated with tofu quality traits. In this study, five key traits, namely water absorption (WA%), Brix of soymilk (°BS), soymilk yield (YM%), tofu residue (TR%), and tofu yield (YT%), were evaluated in two recombinant inbred line (RIL) populations: 81 lines of “Daepung”דSaedanbaek” and 122 lines of “Daepung”דGalchae”. Most traits exhibited normal distributions and transgressive segregation. Trait correlations revealed strong associations between WA and TR, and between YM and YT, with population-specific variation. Quantitative trait locus (QTL) mapping identified eight loci in each population linked to WA, °BS, YM, TR, and YT across multiple chromosomes. Notably, co-localized QTL were detected for WA% and TR% (chromosomes 1 and 6) and for WA%, YM%, °Brix, and TR% (chromosome 8), indicating pleiotropic regulation. Candidate genes included Glyma.06g173500, associated with β-glucan biosynthesis, and Glyma.03g132700, encoding β-glucanase, both implicated in seed coat permeability and tofu yield. These results provide novel genetic insights into seed coat properties and processing quality, and the identified QTLs and candidate genes represent valuable targets for marker-assisted selection in soybean breeding programs optimized for tofu production in Korea.

A soybean cultivar, “Seonyu2ho” for double cropping using soy-paste and tofu was developed in 2011 using the pedigree method by crossing “Milyang235ho” and “Jungmo3004ho.” A promising line, YS2441-B-2S-11-3, was selected and named as “Milyang334.” It demonstrated prominent early maturing, shattering resistance, and high yield in regional yield trials (RYTs) from 2017 to 2019, and was released by the name “Seonyu2ho.” The cultivar showed a determinate growth habit, white flowers, grey pubescence, yellow seed coat, yellow hilum, flat-spherical seed shape, and large seed size (27.9 g per 100 seeds). “Seonyu2ho” matured on October 5 (112-growing day cycle) in RYT and was suitable for double cropping with winter crops, such as wheat, barley, and onion. It was resistant to bacterial pustule and soybean mosaic virus and tolerant to lodging in fields. Particularly, “Seonyu2ho” showed a high yield (3.34 ton/ha) and shattering resistance, even if the previously developed early matured cultivars exhibited low yield and easy shattering. Overall, “Seonyu2ho” can contribute to stable soybean production in double cropping.

Tofu is produced by mixing condensed soymilk with a coagulant. It has a low calorie and high protein and contains various important vitamins and minerals; therefore, consumption of tofu as a healthy and dietetic food has increased worldwide. For systematic application in breeding programs to increase tofu yield, evaluation of tofu characteristics is essential. To test the various characteristics of tofu, typically, a considerable amount of seeds (approximately 100 g, is required. Here, we propose a simple tofu quality test method requiring a small amount of seeds (15 g), which is 75% less than the amount needed for conventional testing. Tofu was manufactured using 20 soybean varieties with a conventional method (i.e., a tofu making machine, TM) and four simple methods: natural filtering (NF), weight pressure (WP), hand pressure (HP), and rotation machine (RM). The correlation between the five methods was assessed with respect to each tofu characteristic, and the HP and RM methods were statistically similar to the conventional methods, whereas the other methods showed differences. Regarding tofu yield, the HP and RM methods showed significantly higher correlation coefficients of 0.79 and 0.78, respectively, and the coefficient of variation between replications was also low. Therefore, the HP and RM methods were the best to easily characterize the tofu yield using a small amount of seeds. Considering the efficiency of the test, the RM method appears to be more effective than the HP method for testing multiple lines. These results will be used for the identification of quantitative trait locus/genes related to tofu quality and marker-assisted selection of breeding new soybean varieties.

A yellow soybean cultivar called ‘Hipro’ was developed using the single seed descent (SSD) method by crossing ‘Saedanbaek’ (SS92414 ×MD87L) and ‘Daepung’ (Baekwon × Sinpaldal2). A preliminary yield trial (PYT), advanced yield trial (AYT), and regional yield trial (RYT) were conducted in three regions. ‘Hipro’ has a determinate growth habit, white flowers, and a spherical seed shape. In the regional yield trial, the flowering and maturity dates of ‘Hipro’ were August 4 and October 17, respectively, and the 100-seed weight was 22.2 g, which was lower than that of Daewon (26 g). Additionally, ‘Hipro’ showed resistance to lodging, soybean mosaic virus (SMV), bacterial blight, and pod shattering. The seed protein content of ‘Hipro’, which was of particular interest in this study, was 53.9%, which was higher than that of ‘Daepung’ (41.5%), and the total amino acid content without tryptophan was 43.6%, 19% higher than that of ‘Daepung’. The mean yield of ‘Hipro’ in RYT was 2.23 ton/ha, which was 91.3% of the yield of ‘Daewon’. However, ‘Hipro’ showed an 11% higher yield than Daewon in Paju. As a result of the tofu characteristic test, 'Hipro' is suitable for making soy milk and tofu due to its high solid content (12.67 Brix) and protein content (13.68%) and high yield (325%) of tofu. Overall, ‘Hipro’ had high protein content, excellent processing quality for tofu and soy milk, and strong resistance to disease and pod shattering that will greatly contribute to the consumption of soybeans in Korea. (Registration No. 7735).

The soybean cultivar, ‘Saegeum’, has been developed for preparing soy-paste and tofu. The soybean cultivars ‘Daepung’ and ‘SS98207-3SSD-168’ were crossed in 2003 to obtain ‘Saegeum’. Single seed descent method was used to advance the generation from F₃ to F₅, and the plant lines with promising traits were selected from F₆ to F₇ by pedigree method. The preliminary yield (PYT) and advanced yield trials (AYT) were conducted from 2009 to 2010, and the regional yield trial (RYT) was conducted in 12 regions between 2011 and 2013. The morphological characteristics of ‘Saegeum’ were as follows: determinate plant type, white flower, tawny pubescence color, and brown pod color. Flowering and maturity dates were August 2, XXXX and October 17, XXXX, respectively. Plant height, first pod height, number of nodes, number of branches, and number of pods were 79 cm, 18 cm, 16, 2.3, and 44, respectively. The seed characteristics of ‘Saegeum’ were as follows: yellow spherical shape, yellow hilum, and the 100-seed weight was 25.4 g. ‘Saegeum’ was resistant to bacterial pustule and SMV in the field test, and its lodging resistance was mildly strong, whereas its shattering resistance was excellent. The ability of this cultivar to be processed into tofu, soybean malt, and other fermented products was comparable with that of ‘Daewonkong’. The yield of ‘Saegeum’ in the adaptable regions was 3.02 ton ha^-1. Thus, ‘Saegeum’ is adaptable to mechanized harvesting because of its high first pod height, as well as lodging and shattering resistance. (Registration number: 5929)

The soybean cultivar ‘Neulchan’ was developed for production of soy-paste and tofu. SS91501-9-1-1 and SS96205 (F₂) were crossed in 1998, and F₃ to F₇ were selected by the pedigree method. A preliminary yield trial (PYT) and an advanced yield trial (AYT) were conducted from 2006 to 2008, and a regional yield trial (RYT) in nine regions was conducted from 2009 to 2011. In the RYT, ‘Neulchan’ was stable in variable environments and generated high yield. ‘Neulchan’ was determinate with white flower, light brown pod color, yellow spherical seed, and yellow hilum. Its flowering date and maturity date were Jul. 30 and Oct. 9, respectively. The plant height was shorter than that of ‘Daewonkong’ (a standard cultivar). ‘Neulchan’ had the same node number (14), higher first-pod height (12 cm), and lighter seed weight (21.7 g/100-seed weight) than those of ‘Daewonkong’ (14, 11, and 24.2 g/100-seed weight, respectively). ‘Neulchan’ had high resistance to bacterial pustule, and its resistance to soybean mosaic virus was similar to that of ‘Daewonkong’. The yield and color of ‘Neulchan’ tofu were similar to those of ‘Daewonkong’ tofu, but the hardness was lower than that of ‘Daewonkong’ tofu. The soybean malt scent, fermented soybean yield, and γ-polyglutamic acid (γ-PGA) of ‘Neulchan’ were 3, 215%, and 24.6 mg/g, respectively. Its yield in adaptable regions was 307 kg/10a, higher than that of ‘Daewonkong’. ‘Neulchan’ was expected to be cultivated and used widely for soy-paste and tofu production. (Registration No. 4904).

A soybean cultivar “Chamol” for double cropping for use as soy-paste and tofu was developed using a pedigree method in 2011 as a cross between “Shinpaldal2” and “Keunol.” A promising line, SS99502-2B-89-1-3-4-1-1, was selected and designated as “Milyang210”. It was promising and showed good results from regional yield trials (RYTs) for 3 years from 2009 to 2011 and released with the name “Chamol.” It has a determinate growth habit, white flowers, gray pubescence, yellow seed coat, yellow hilum, spherical seed shape, and large seeds (27.7 g per 100 seeds). The maturity date of “Chamol” was September 18 (100 day growing period) in RYT and it is suitable for double cropping with winter crops such as onion. “Chamol” was resistant to bacterial pustule and soybean mosaic virus and tolerant to lodging in fields. Furthermore, the average yield of “Chamol” was 2.51 ton/ha in the regional yield trials conducted for 3 years from 2009 to 2011.

The soybean cultivar ‘Gangpoong’ was developed for soy-paste and tofu. Suwon 223 and SS 00419 were crossed in 1999 and their progenies were selected from F₃ to F₅ using the pedigree method. Preliminary yield (PYT) and advanced yield (AYT) trials were conducted from 2008 to 2010, and regional yield trials (RYT) were conducted at three locations from 2011 to 2013. In RYT, ‘Gangpoong’ was stable in variable environments. ‘Gangpoong’ was determinate, with white flowers, yellow elongated spherical seeds, and a light brown hilum. The flowering and maturity dates were July 27 and October 8, respectively. The plant height was 67 cm shorter than that of ‘Daewonkong’ (81 cm, standard cultivar). ‘Gangpoong’ had fewer node numbers (16) than that of ‘Daewonkong (18) and had a heaver seed weight (30.1 g/100-seed weight) than that of ‘Daewonkong (26.0 g/100-seed weight)’. ‘Gangpoong’ showed lodging tolerance. The tofu yield of ‘Gangpoong’ was 213%, and the physical characteristics of tofu were similar to those of ‘Daewonkong (208%, standard cultivar)’. The soybean malt scent and fermented soybean yield of ‘Gangpoong’ were 2 and 105%, respectively. The yield in adaptable regions was 3.4 MT/ha, which was 14% higher than that of ‘Daewonkong’. Therefore, ‘Gangpoong’ could be cultivated and used widely for soy-paste and tofu in the near future (Registration number: 5932).

Soybean cultivar ‘Seonpung’ was developed for soy-paste and tofu. Suwon 224 and YS1325-3S-2 were crossed in 2003 and selected from F₃ to F₅ by pedigree method. The preliminary yield trial (PYT) and advanced yield trial (AYT) were conducted from 2009 to 2010, and regional yield trial (RYT) in twelve regions was conducted from 2011 to 2013. In RYT, ‘Seonpung’ was stable in variable environments and a high yield cultivar. ‘Seonpung’ is determinate, white flower, yellow spherical seed and yellow hilum. Flowering date and maturity date were Aug. 5 and Oct. 19, respectively. Plant height was similar to ‘Daewonkong (standard cultivar)’. However ‘Seonpung’ has higher node number (16) and seed weight (25.9g/100-seed weight) than ‘Daewonkong’ (14 and 24.2g/100-seed weight). ‘Seonpung’ is resistant to root rot, and it also has high level of resistance to bacterial pustule and soybean mosaic virus. The yield of tofu of ‘Seonpung’ was 241%, and noticeably lighter, and solidity was higher than ‘Daewonkong’. Soybean malt scent, fermented soybean yield and γ-polyglutamic acid (γ-PGA) of ‘Seonpung’ were 4, 181% and 31.7㎎/g. The yield in adaptable regions was 340kg/10a (21% increase compared to ‘Daewonkong’). ‘Seonpung’ is expected to be cultivated and used widely for soy-paste and tofu. (Registration number: 5931)

A new soybean cultivar ‘Manpoong’ for tofu soybean was released by ARES, Gyeunggi Province in 2009. The goals of breeding were for large seed size, high yield, and resistance to disease such as bacterial pustule. ‘Manpoong’ was derived from the cross between ‘Dongsan 121’, which has large seed size, yellow seed coat, and characteristics of superior tofu, and ‘Sprite 87’, which has early maturity. The preliminary, advanced and regional yield trials for evaluation and selection were carried out in 2003 and from 2005 to 2009, respectively. ‘Manpoong’ has a determinate growth habit with white flower, grey pubescence, dark brown pod color, yellow seed coat, yellow cotyledon, elongated seed shape, and large seed size(29.5 g per 100 seeds). The maturing date was Sept. 29. The content of crude protein, crude oil, unsat. fatty acids, isoflavone, total amino acid which affected the production rate of tofu was higher than those of the check cultivar ‘Taekwangkong’. The production rate of tofu was 15 percent higher than the check cultivar ‘Taekwangkong’. The average yield of ‘Manpoong’ was 2.87 MT/ha in the regional yield trials(RYT) carried out in two location at double cropping system in Korea from 2007 to 2009, which was 12 percent higher than the check cultivar ‘Taekwangkong’.