• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.100-100
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• 2017

FT is one of the major floral activator in plant flowering. FT determines the changing point of time from vegetative stage to reproductive stage. To understand the role of FT homologs in short-day plant soybean, we identified 10 soybean FT homologous genes and named GmFTs. We figured out that 10 GmFT genes were further categorized into three subclades through phylogenetic analysis. Expression analysis of GmFT genes indicated that they might have different functions in photoperiod-dependent soybean flowering. Most of GmFTs, for example, GmFT2a, GmFT2b, GmFT5a and GmFT6 mainly expressed in soybean leaves at short-day condition. However, interestingly GmFT1a and GmFT4 represented opposite expression pattern to other GmFTs. Arabidopsis transgenic plants overexpressing GmFT2a and GmFT5a exhibited extremely early flowering. In contrast, overexpression of GmFT4 delayed flowering of Arabidopsis transgenic plants. The results suggest that GmFT4 has antagonistic role to other GmFTs in soybean flowering. Interestingly, mRNA level of GmFT2a is higher in early flowering soybean accessions than in late flowering ones. Moreover, the highest point of mRNA level of GmFT2a showed the positive correlation with the timing of flowering of soybean accessions. But that of GmFT4 showed opposite pattern. Here, we report that soybean FT homologs might acquire different functions in photoperiod-dependent flowering through the functional diversification during evolution.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.47-55
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• 2020

This study was conducted to evaluate the flowering characteristics of 22 soybean (Glycine max Merrill) varieties of North Korea and classify the flowering group by the flowering date. The flowering date and the days required for flowering with the different planting times on May 31, June 19, June 30, July 3, and July 4 were investigated at the agricultural experimental field of Korea University for three years from 2017 to 2019. The flowering date and the days for flowering of "Yeonpungkong", an early maturing soybean cultivar of Korea, were July 18 and 48 days, respectively, at the planting time of May 31, those of "Daewonkong", a mid-late maturing cultivar, were July 30 and 60 days, respectively. Based on the flowering dates of "Yeonpungkong" and "Daewonkong", North Korean soybean varieties were classified into six flowering groups. Eight North Korean soybean varieties had the flowering dates earlier than "Yeonpungkong", including "Brekkhat" classified into the early flowering group. The range of flowering date was July 2 to 15 at planting time of May 31. Twelve North Korean soybean varieties had flowering dates similar to or later than "Daewonkong", including "Chang Dan Bac Mok" classified into the mid-late flowering group. The range of flowering date was July 24 to 30 at the planting time of May 31. For flowering response to environmental stimulus, all of the mid-late flowering varieties of North Korea responded to "photosensitive or day-length" for flowering reaction. The early flowering varieties were divided by "photosensitive" response and "temperature" response variety.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.25-30
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• 2003

This research was conducted to compare the dry matter production and the yield productivity among nine soybean cultivars by measuring the photosynthetic ability of the middle and lower leaves at the flowering and the seed development stages. The leaf greenness(SPAD value) were ranged as 32-42 at the flowering stage. Also, They were ranged as 25-40 and 38-51 at the fifth leaf and the seventh leaf, respectively. The photosynthetic ability at the flowering and the seed development stage showed significant differences among soybean cultivars, and the photosynthetic ability at the seed development stage showed higher difference among cultivars than the flowering stage. The variation of the photosynthetic ability at the flowering and the seed development stage also was significant among cultivars. The light saturation point at the flowering stage was about 1500 $\mu$mol $m^{-2}$ $s^{-1}$ PAR, and the seed development stage was about 1000 $\mu$mol $m^{-2}$ $s^{-1}$ PAR. The photosynthesis showed the high negative correlation with the leaf area and the positive correlation with the leaf area ratio. Also, photosynthesis at seed development stage showed positive correlation with grain yields but there was not significant between photosynthesis and yields at flowering stage..

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.129-132
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• 1969

The polygenic variation in flowering time of soybean irradiated with Co$^{60}$ gamma ray evaluated in the R$_2$ generation. The genetic variance in the irradiation treatment was about four times that of the control. The basic possibility of selection for the early and the late in flowering time of soybean after irradiated with Co$^{60}$ was suggested in this paper.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.5
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• pp.282-287
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• 2000

Soybean [Glycine max (L.) Merrill] crops, grown in a rice soybean rotation, can suffer when grown in soil with excessive moisture. The objective of this work were to determine the reduction in growth and yield, responses of vegetative and reproductive growth of soybean to excessive soil moisture achieved by prolonged irrigation. Responses of different cultivars were determined at growth stages from V6 to R8 to clarify the sensitive growth stages or characteristics to excessive soil moisture. Cultivar differences in response to excessive soil moisture condition were conspicuous in seed dry weight and harvest index (HI) but not in the response of seed number or pod number per plant. The timing of irrigation causing the condition of excessive soil moisture influenced the vegetative or reproductive traits. Soybean plants were more affected by irrigation commencing at the pre-flowering than at the post-flowering stage. Post-flowering irrigation did not reduce growth of vegetative organs significantly; in fact the growth of stems and leaves was facilitated by the prolonged irrigation commencing at flowering. Differences between cultivar response to prolonged irrigation were assumed to relate to the reduced amount of assimilates translocated to the reproductive organ.

• Journal of Plant Biology
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• v.22 no.1_2
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• pp.1-4
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• 1979

Wild soybean plants(Glycine ussuriensis) collected from Korea(47 strains) and abroad(41 strains) were grown under field condition and classified according to the growth habit. Seeds were analyzed for protein content. The results were as follows: 1. Wild soybean plants were classified into three groups each by seed size, growth habit of stem, leaf size and flowering time. 2. Seed protein was higher in the strains with large leaves, tendril, stem or late flowering. 3. Glycine gracilis, supposed to be the intermediate species between cultivated and wild soybean(according to the stem growth habit, straight or semitendril, and seed size) was medium in protein content of seeds. 4. The average protein content of Glycine ussuriensis, 43.2%, was highest in comparison with those of others such as G. gracilis, 37.5%, or G. max, 36.2%. 5. One hundred seed weight of Amphicarpaea trisperm, similar to the wild soybean, was almost same as Glycine ussuriensis, but protein content of this species was lower than wild soybeans.

• 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.55 no.1
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• pp.19-23
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• 2010

This study was performed in order to determine the relationship between anthocyanin generation and seed coat pigmentation in black soybean. Soybean genotypes were analyzed the individual anthocyanin contents by UPLC, which were sampled at 5-day intervals from the 35th day after flowering. Ilpumgeomjeongkong had begun to accumulate anthocyanin on the seed coat previous 35 days after flowering, and in case Heugcheongkong was 30 days. The seed coat coloration in Ilpumgeomjeongkong run on till the 45th day after flowering, and that of Heugcheongkong was between 55 and 60days after flowering. Cyanidin-3-Glucoside (C3G) was formed the earliest and accumulated the greatest among three anthocyanin pigments existed in black soybean. So we could be concluded that C3G affected on seed coat pigmentation greatly than other pigments. The anthocyanin contents at maturity in Ilpumgeomjeongkong was 4.4 times higher than at beginning stage of anthocyanin formation, while those of Heugcheongkong was 2.5 times.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.103-108
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• 1996

The changes in major characteristics of vegetable soybean at different stages were investigated. The 100-seed weight of vegetable soybean had a tendency to increase before 43 days after flowering, but decrease slightly after then. After 37 days after flowering, the sucrose content of Douya had a tendency to decline and in case of Shirofusa, total sugar content was sharply decreased at 40 days after flowering. The total vitamin C content of Douya and Shirofusa was dramatically increased at 37 days after flowering and then got the plateau, otherwise the total vitamin C content of Shirofumi and Hwaeomputkong was the highest level at 43 days after flowering. The hardness changes of vegetable soybeans were tend to increase according days after flowering. In sensory evaluation, preference score was significantly associated with harvesting stages. Correlation coefficient between sweetness and beany taste was significantly negative.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.104-118
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• 2009

This study was carried out to classify Korean soybean varieties base on maturity group (MG) and to find character relationships according to planting date for high quality soybean seed production adapted to early season cultivation environment of Miryang. Results of maturity grouping of Korean soybean varieties showed that Keunol (3 cultivars), belonged to Group 0; Seonnok and Danmi in Group II, Shinrok in Group III, Seonyu (17 cultivars), in Group IV, Taekwang (44 cultivars) in Group V, Daewon (25 cultivars) in Group VI, and Kwangdu and Keumdu in Group VII. Agronomic characteristics of 100 soybean varieties were compared based on MG, cultivation year and seeding date. Soybean varieties belonging to the MG $VI{\sim}VII$ showed longer days to flowering and growth period, high lodging density and higher yield. Seed quality analysis revealed that as maturity was delayed, seed weight becomes heavier while seed cracks become abundant. In addition, occurrence of purple seed and phomopsis were higher in MG $0{\sim}III$. Protein content was higher in MG $0{\sim}III$, and isoflavone content was higher as maturity was delayed. On the other hand, lipid content was generally similar across MGs. Correlation analysis of major agronomic characters showed positive relationships between days to flowering and growth days, seed weight and lodging in MG $IV{\sim}V$, seed crack and growth days in MG $0{\sim}III$, seed crack and days to flowering in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and lodging in MG $IV{\sim}V$ and MG $VI{\sim}VII$, seed crack and seed weight in MG $IV{\sim}V$ and MG $VI{\sim}VII$, purple seed and growth days in MG $IV{\sim}V$, purple seed and seed weight in MG $VI{\sim}VII$, phomopsis and growth days in MG $IV{\sim}V$ and MG $VI{\sim}VII$, and phomopsis and purple seed in MG $IV{\sim}V$ and MG $VI{\sim}VII$. In contrast, a negative relationship was observed between seed weight and lodging in MG $0{\sim}III$. Correlating yield and major characters revealed negative relationships between days to flowering and growth days in MG $0{\sim}III$ and MG $IV{\sim}V$, whereas positive relationships were obtained on MG $VI{\sim}VII$ seeded on April 30. Lodging, seed weight and seed crack were all negatively correlated with yield in the MG $IV{\sim}V$ and MG $VI{\sim}VII$. Soybean cultivars identified as adaptable to early season planting for production of high quality soy curd and fermented soybean paste were Seonyu, Kwangdu, and Soho while those suited for the manufacture of soybean sprouts were Sobaeknanul, Kwangan, Sowon, and Bosuk. Geomjeong 2 chosen as best for mixing with rice.