• Korean Journal of Plant Resources
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• v.20 no.2
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• pp.145-149
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• 2007

Shape of soybean sprouts affects their marketability. This study was carried out to understand the effects of pressure in both overspraying and underwatering cultivation methods on growth and morphological characteristics of soybean sprouts. Pressing treatments were done by continuous pressing by laying a plastic culture box over another with growing the sprouts, their alteration every day, or no pressing in overspraying method, and by continuous pressing, pressing after the 4th day cultivation with 30 kg steel case, or no pressing in underwatering method. The soybean (cv. Junjery) seeds were soaked in 2 ppm BA solution for 5 hours and then aerated for 3 hours immediately before 6 day culture. Lateral roots, hypocotyl and root lengths, hypocotyl diameters, fresh and dry weights were measured. Lateral roots per sprout were decreased with stronger pressing regardless of watering methods. In overspraying method, continuous pressing treatment resulted in shortest hypocotyl, but no and ones did the longest root. In underwatering method, however, no pressing one showed the longest hypocotyl but continuous pressing did the shortest hypocotyl. Regardless of watering methods, middle part of hypocotyl was more thickened with stronger pressing although hook diameters of the 3 treatments were not affected. In overspraying method. total fresh weight per sprout was the least in no pressing but the greatest in continuous pressing. In underwatering method, however, there was no significant difference between the treatments.

• Korean Journal of Plant Resources
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• v.19 no.2
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• pp.344-347
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• 2006

Watering methods for soybean sprouts could be mainly divided into two groups of overspraying and underwatering. The study was carried out to determine the effect of water supplying method on growth, morphological characteristics, colour and cutting resistance of soybean (cv. Junjery) sprouts and culture temperatures. The morphological characters, fresh and dry weights were measured on the 6th day after their culture, but daily mean temperatures inside the plastic culture boxes were measured by data-loggers. Lateral roots were more formed in the underwatering method (UM) than in the overspraying method (OM). Although their total lengths of both methods were nearly same, OM had longer hypocotyl but UM did longer root than the other. Middle and upper parts of hypocotyl were more thickened in UM than in OM. UM showed more hypocotyl fresh and dry weights than OM. There was, however, no significant difference between the two methods in cotyledon, root, total fresh and dry weights although the culture temperature was higher in OM than in UM.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.325-330
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• 2004

This study was carried out to determine adequate planting date, to compare the growth characteristics between early and late maturing cultivars, and to provide the data for the cultivation techniques of soybean [Glycine max (L.) Merr.] in double cropping system with winter crops on paddy field in Korea. Cultivars were planted on 26 May, 16 June, and 7 July with a planting density of $70cm(row\;widtb)\;{\times}\;10cm$ (planting spacing). Seed yield of soybean planted on June 16 and July 7 was approximately $37\%\;and\;53\%$, respectively, less than that of conventional planting date of May 26 in Pungsan-namulkong, and planted on June 16 and July 7 was about $30\%\;and\;37\%$, respectively, less then that of conventional planting date of May 26 in Hanamkong. The number of pods and seeds per plant decreased as planting date delayed. Seed weight increased in Pungsan-namulkong but decreased in Hannamkong as planting date delayed. The flowering date was late in delayed planting plots, but it was shorted for days from emergence to flowering and from emergence to maturity. The plant height of Hannamkong was greater than Pungsan-namulkong from the emergence to flowering stages, but in contrast, it was greater in Pungsan-namulkong than Hannamkong after flowering stage (50d after emergence) when it planted on May 26. There were no significant differences between two soybean cultivars at planting dates of June 16 and July 7. Leaf number, leaf area, and dry matter were also reduced by late planting, and Both of them were shown in high reduction at the later planting. There was a high significant difference at the flowering $(r\;=\;0.87^{**})$ and pod formation $(r\;=\;0.91^{**})$ stages between leaf dry matter and seed yield. Crop growth rate (CGR) was greater at $R2\~R3$ growth stages compared to $R3\~R4\;or\;R4\~R5$ growth stages in two soybean cultivars and the greatest CGR was obtained at planting date of May 26 in two soybean cultivars except for R4-R5 growth stage in Pungsan-namulkong. There was a highly significant positive difference between the seed yield and the leaf area index (LAI) across R3 to R4 and R2 to R3 stages. The photosynthetic rate $(P_N)$ of the uppermost leaf position had no significant difference among planting dates and between two soybean cultivars. However, $P_N$ of the $7^{th}$ leaf position increased as the planting date delayed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.25 no.4
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• pp.59-65
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• 1980

An attempt was made to survey soybean cultivars that were nonsensitive to the photoperiod for selection as possible breeding materials for wide area adaptable varieties. Fifty-five cultivars were subjected to different day length conditions. The number of days from sowing until flowering was shortened under short day length conditions, and late varieties tended to be more sensitive to day length than early varieties. The response to day length of the tested cultivars might be divided into three groups; low, intermediate and high degree, by their accelerated rate of flowering. Especially four varieties in the low responding group, Gembokin, Wirth, Wayne and Pi.54613 were identified to be nonsensitive to day lengths, that is, neutral varieties. They also showed little variation in morphological characteristics under different day length conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.2
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• pp.96-102
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• 2003

This study was conducted to determine the effects of two plant populations (28 and 14 plants per $m^2$) and two toppings in conventional plant population (28 plants per $m^2$) on soybean (Glycine max L. cv. Pungsannamulkong) cultivated in the paddy field. The two topping time were taken at 6$^{th}$ to 7$^{th}$ and 8$^{th}$ to 9$^{th}$ trifoliolate leaf stages in the conventional plant population. Experimental design for growth data was a randomized complete block with three replications, and samples were taken at R1 (July 31), R3 (August 19), R5 (September 2) and R7 (September 23) growth stages. The branch number of soybean was relatively higher in the low plant population (14 plants per $m^2$) and with the topping at the 6$^{th}$ to 7$^{th}$ leaf stage, in the conventional plant population (28 plants per $m^2$), and with topping at the 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage in descending order. The highest average branch length of soybean was observed in the low population and the longest branch length was observed from the soybean with topping at the 6$^{th}$ to 7$^{th}$ leaf stage. The leaf number per plant was decreased in order of in the low population, with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage, with the topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage, and in the conventional population. The leaf area was high in the low population and with topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with the topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage in soybean. The dry weight of leaves and branches was high in the low population and with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage. The leaf number per plant was high in the low population and with topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage and was relatively low in the conventional population and with topping at 8$^{th}$ to 9$^{th}$ trifoliolate leaf stage. The grain yield per 10a was high with the topping at 6$^{th}$ to 7$^{th}$ trifoliolate leaf stage.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.201-201
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• 2017

Delayed stem senescence of soybean is a phenomenon of retarded leaf and stem yellowing, where plants maintain a high stem water content and remain chlorophyll in leaf and stem at maturity stage. This phenomenon was one of the most important physiological disease in Japanese soybean cultivation. The occurrence of delayed stem senescence was affected by sowing time. And the most of Japanese field, soybean seeds were sowed in June. June is the rainy season in Japan, and the soil water content of field become higher in this season. In this study, the effects of late sowing (July sowing) on the yield and the occurrence of delayed stem senescence in soybean cultivars Enrei, Tachinagaha and Ayakogane were examined from 2013 to 2015, in the experimental farm at Nihon University (Fujisawa-city, Kanagawa, Japan). The seeds of all cultivars were sowed in June (June-normal density plot) or July (July-normal density plot, July-high density plot and July-super high density plot) in field experiment. The pot experiments were carried out in 2014. In all cultivars, the yield of July-high density plot and July-super high density were higher than that of June normal density plot. And the yield of June-normal density plot was the same as that of July-normal density plot. In all cultivars, the occurrence of delayed stem senescence was increased by seeding in June sowing. And in July sowing plots, no significance difference in the occurrence of delayed stem senescence was observed among density plots. One of reason about the increasing the occurrence of delayed stem senescence in June-normal plot was the increasing of the damaged seeds by bean bugs. Add one of reason about the decreasing of the occurrence of delayed stem senescence of July plots was the decreasing of the amount of cytokinin supplied from root to top and water stress after the flowering time was improved compared with the June plot. In conclusion, the yield of Enrei, Tachinagaha and Ayakogane were not changed by changing the sowing time from June to July. In all cultivars, the occurrence of delayed stem senescence were decreasing by seeding in July.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.299-299
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• 2017

Due to the climate changes in Korea, the numbers of both torrential rain events and drought periods have increased in frequency. Water management practice against water shortage and flooding is one of the key interesting for field crop cultivation, and groundwater often serves as an important and safe source of water to crops. Therefore, the objective of this study is to evaluate the effect of groundwater table levels on soil water content and soybean development under two different textured soils. The experiment was conducted using lysimeter located in Miryang, Korea. Two types of soils (sandy-loam and silty-loam) were used with three groundwater table levels (0.2, 0.4, 0.6m). Mean soil water content during the soybean growth period was significantly influenced by groundwater table levels. With the continuous groundwater level at 0.2m from the soil surface, soil water content was not statistically changed between vegetative and reproductive stage, but the 0.4 and 0.6m groundwater table level was significantly decreased. Lower chlorophyll content in soybean leaves was found in shallow water table treatment in earlier part of the growing season, but the chlorophyll contents were non-significant among water table treatments. Groundwater table level treatments were significantly influenced on plant available nitrogen content in surface soil. The highest N contents were observed in 0.6m groundwater table level. It is probably due to the nitrogen loss by denitrification as the result of high soil water content. The length and dry weight of primary root was influenced by groundwater level and thus the highest length and dry weight of root were observed in 0.6m water table level. This result showed that soybean root growth did not extend below the groundwater level and increased with the depth of groundwater table level. The results of this study show that the management of groundwater level can influence on soil characteristics, especially on soil water content, and it is an important practice of to reduce yield loss caused by the water stress during the crop growing season.

• The Korean Journal of Food And Nutrition
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• v.26 no.2
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• pp.318-322
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• 2013

This study was designed to investigate changes in germination characteristics and color as well as the content of isoflavones of Eunhakong germinated under dark conditions. The wet weight of Enhakong was increased as germination progressed. It reached $299.7{\pm}15.0%$ at 60 h after the beginning of sprouting. The relative dry weight was consistently decreased as germination progressed, and it reached $65.8{\pm}8.2%$ at 60 h after the beginning of sprouting. The length of sprout was rapidly increased at the latter stage compared to the beginning of germination. Most soybean seeds were successfully germinated at 60 h after beginning of sprouting. The L value was considerably increased at the early stage of germination and it reached $63.4{\pm}0.7$ at 60 h. The a value was rapidly increased at the beginning of germination and decreased thereafter. The b value was increased at the beginning of germination and did not changed thereafter. It was confirmed that the total isoflavone content, in which the m-genistin was highest followed by daidzin, and than slightly decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.323-329
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• 1987

Five soybean varieties of two early maturing Karikei73 and SS 79168, and three late maturing Tohoku76, Baegunkong and Jangbaegkong were used and evaluated in the study. Of the varieties examined, Karikei73 was characterized by the delayed leaf senescence. The varieties were planted in the pots of 1/3500 a filled with volcanic ash soil at the experimental fields of the National Institute of Agrobiological Resources in Japan. Major agronomic characteristics including the activity of nitrogen fixation for root nodules during the grain filling period were measured. Measurements during the stages were followed by the stage of development descriptions for soybeans made by Fehr and Carviness (1977). The acetylene reducing activity (ARA) per dry weight of root nodule measured using acetylene reduction assays was the highest at R4-R4.5 with decreasing trends thereafter for the early matruing varieties, while it continuously increased up to R6 but decreased rapidly thereafter for the late maturing varieties. The dry weights of root nodules and all parts of the host plant at each stage checked were greater in the late maturing varieties being the same in ARA per pot.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.253-260
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• 2010

Plant secondary metabolites have always been a focus of study due to their important roles in human medicine and nutrition. We transferred the isoflavone synthase (IFS) gene into soybean [Glycine max (L.) Merr.] using the Agrobacterium-mediated transformation method in an attempt to produce transformed soybean plants which produced increased levels of the secondary metabolite, isoflavone. Although the trial to produce transgenic plant failed due to unestablished hygromycin selection, transformed callus cell lines were obtained. The induction rate and degree of callus were similar among the three cultivars tested, but light illumination positively influenced the frequency of callus formation, resulting in a callus induction rate of 74% for Kwangan, 67% for Sojin, and 73% for Duyou. Following seven to eight subcultures on selection media, the isoflavone content of the transformed callus lines were analyzed by high-performance liquid chromatography. The total amount of isoflavone in the transformed callus cell lines was three- to sixfold higher than that in control callus or seeds. Given the many positive effects of isoflavone on human health, it may be possible to adapt our transformed callus lines for industrialization through an alternative cell culture system to produce high concentrations of isoflavones.