• Proceedings of the Korean Society of Crop Science Conference
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• 2023.04a
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• pp.128-128
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• 2023

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.16-21
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• 1992

Increase in nodulation and nitrogen fixation was achieved partly through the isolation of supernodulating soybean mutant plants. This experiment was conducted to compare nodulation, nitrogen fixation, and early growth characters of wild type 'Bragg' with those of its supernodulating soybean mutant, 'nts 382' and 'nts 246'. At 31 days after planting, nodule dry weight of nts mutants was 2.5 to 3.7 times greater than that of Bragg. Higher nodulation of nts mutants showed the reduced top growth, indicating that photosynthates might be translocated and used for nodule growth attached to the root system. Total acetylene reduction activity was higher in nts mutants than Bragg, whereas specific acetylene reduction activity of nts mutant was the half of that of Bragg. Mixture of nts mutants and Bragg did not affect nodulation characters each other, suggesting that factors affecting supernodulating characters exist inside rather than outside the root system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.145-149
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• 2001

This study was performed to evaluate the growth and nodulation characters of hypernodulating soy-bean mutant, SS2-2, and to know the growth and yield performance of the mutant in infertile soil. Soil fertility was adjusted by mixing the different ratios of soil components including clay, river sand, and horticultural bed, which resulted in fertile and infertile soil. Dry weight, nitrogen concentration, and leaf nitrate reductase of each plant were measured around V6 stage (47 days after planting) and around R3 stage (82 days after planting). There were significant effects of soil fertility and soybean genotype on the total dry weights including root, nodule, stem, leaf, and pod dry weight at V6 and R3 stages. Total dry weight of hypernodulating mutant, SS2-2, was clearly less than that of its wild type, Sinpaldalkong 2. However, nodule development on the roots of SS2-2 was much greater than that of Sinpaldalkong 2, regardless of soil fertility. Though SS2-2 was smaller in plant size than Sinpaldalkong 2, genotypic difference in total nitrogen content was not significant at both V6 and R3 stages because SS2-2 fixed more nitrogen biologically than its wild type in the root nodule. The SS2-2 mutant showed lower plant yield in both infertile and fertile soil. The SS2-2 contained more crude seed protein than Sinpaldalkong 2, and was characterized with reduced top and root growth.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.4
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• pp.365-372
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• 2012

Native of soybean aphid (Aphis glycines Matsumura) is an Asia and aphid is one of the dangerous pests in soybean [Glycine max (L.) Merr.]. High density aphid populations can reduce crop production by causing severe damage. The objective of this study was evaluation of resistance to the soybean aphid in soybean cultivars and germplasms. A total of fifty five soybean cultivars or germplasms, including two susceptible and two resistant check varieties, were infested to evaluate their resistance in the field cage and greenhouse test by aphid colonies which derived from wild collected one soybean aphid biotype in Korea. The average number of reproduced soybean aphid was evaluated with 62.7 aphids in the resistant check variety PI 567598B and also estimated with 1,807 aphids for susceptible check variety Williams 82. In soybean varieties and germplasms, the average reproduced soybean aphid populations ranged from the lowest 497 aphids for Junjeori to the highest 3,862 aphids for Mansu. About seventy six percent of soybean cultivars and germplasms were shown high density soybean aphid populations when compared with another susceptible check variety PI 567543C in the field cage test. From the greenhouse test to evaluate aphid index, 87.3% of soybean cultivars or germplasms presented aphid index with 9.0. No soybean cultivars and germplasms were observed with soybean resistant phenotype when regarded a aphid resistant level as less than 10% aphid reproductions compared with susceptible check Williams 82. Although no Korean soybean cultivars were identified with resistant trait to the soybean aphid, we found one great resistant genetic resource PI 567598B in this study. This result will be helpful to further study for providing useful genetic information for soybean researchers.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.51-54
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• 2007

Soybean has a morphological type with a broadened and flattened stem. Fasciation has been suggested as a new gene for soybean research. SSR marker linked to the $\Large f$ locus that controls fasciation phenotype has not identified within 10 cM. A mapping population consisting of 94 $F_2$ progenies was derived from a cross between wild type Clark (FF) and fasciation mutant C32 (${\Large f}{\Large f}$). The phenotype of $F_2$ individual plants was recorded at R2 and R3 growth stage from field. One-thousand 10-mer oligonucleotide RAPD primers and 29 SSR primers selected from the D1b+W of the soybean molecular linkage map were used. A genetic map was constructed from the segregating 35 RAPD, four SSR markers and one phenotypic(wild type/fasciation) marker. The segregation ratios of 3 : 1 observed in the $F_2$ population and the Chi-square values strongly suggest that the fasciation trait is controlled by a single recessive gene. Satt537 marker was linked to $\Large f$ locus at a distance of 9.6 cM. Assignment of the $\Large f$ locus to linkage group D1b+W and identification of markers can be used as an initial step for fine mapping of the $\Large f$ gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.1
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• pp.69-72
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• 2004

Somaclonal variation, defined as phenotypic and genetic variations among regenerated plants from a parental plant, could be caused by changes in chromosome structure, single gene mutation, cytoplasm genetic mutation, insertion of transposable elements, and DNA methylation during plant regeneration. The objective of this study was to evaluate DNA variations among somaclonal variants from the cotyledonary node culture in soybean. A total of 61 soybean somaclones including seven $\textrm{R}_1$ lines and seven $\textrm{R}_2$ lines from Iksannamulkong as well as 27 $\textrm{R}_1$ lines and 20 $\textrm{R}_2$ lines from Jinju 1 were regenerated by organogenesis from the soybean cotyledonary node culture system. Field evaluation revealed no phenotypic difference in major agronomic traits between somaclonal variants and their wild types. AFLP and SSR analyses were performed to detect variations at the DNA level among somaclonal variants of two varieties. Based on AFLP analysis using 36 primer sets, 17 of 892 bands were polymorphic between Iksannamulkong and its somaclonal variants and 11 of 887 bands were polymorphic between Jinju 1 and its somaclonal variants, indicating the presence of DNA sequence change during plant regeneration. Using 36 SSR markers, two polymorphic SSR markers were detected between Iksannamulkong and its somaclonal variants. Sequence comparison amplified with the primers flanking Satt545 showed four additional stretches of ATT repeat in the variant. This suggests that variation at the DNA level between somaclonal variants and their wild types could provide basis for inducing mutation via plant regeneration and broadening crop genetic diversity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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• pp.23-27
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• 1998

Inhibition of nodule formation and nitrogen fixation by soil nitrogen, primarily nitrate, is well known in legume plants. The present study was undertaken to evaluate the effect of ${NO_3}^-$ on the nodulation, nitrogenase activity, and growth of supernodulating soybean mutant and its wild type. A greenhouse study was conducted to compare two of supernodulating mutants, 'SS2-2' and 'nts 382', with the normal nodulating cultivar 'Sinpaldalkong 2' when grown in a 1-l styroform cup filled with sand, and fertilized with five levels of ${NO_3}^-$ (0, 2, 4, 8, and 12 mM). During the growth period, each plant was supplied two or three times a week with 50 mL of nutrient solution. Supernodulating soybean mutants, SS2-2 and nts 382, showed more nodules and nodule mass, and greater $C_2\;H_2$ activity than the wild type, Sinpaldalkong 2, regardless of the level of exogeneous nitrogen supply. On the other hand, total dry weight of SS2-2 mutant, which was smaller than Sinpaldalkong 2, did not respond to the various ${NO_3}^-$-N levels. This suggested that supernodulating SS2-2 mutant could maintain fairly high total dry weight at the low ${NO_3}^-$-N level, even in the absence of exogeneous ${NO_3}^-$-N in the nutrient solution. From the reduced top growth and high nitrogen fixing ability of supernodulating mutants, it was surmised that supernodulating mutant could potentially protect agricultural environments from pollution through the reduction in nitrogen fertilization as well as maintain fairly high yield with increasing planting density.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.169-175
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• 2007

This experiment was carried out to compare weed occurrence and to evaluate the field performance of some leguminous plant species under no-weeding fallow condition during summer months from middle of June to middle of August. In 2005 and 2006, the first dominant weed species was Digitaria sanguinalis, and other major weed species, such as Cyperus amuricus, Portulaca oleracea, and Amaranthus retroflexus, were similar among treatments. In both years, total shoot dry weight of weeds was the highest In the control plot, and the lowest in the cowpea plot, indicating that cowpea most effectively suppressed the growth of weeds among treatments. When the growth of four different leguminous species were compared after seeding during middle of June in 2006, cowpea and rice bean grew vigorously under no-weeding condition during hot and humid summer months, while wild soybean and hairy vetch did not. Shoot dry weight was in the order of cowpea > rice bean > wild soybean > hairy vetch. In conclusion, cowpea is a leguminous species which can be used as a green manure cover crop during summer months under no-weeding and our climate condition. Further works are needed to use cowpea as a green cover crop during summer months for various cropping systems.

• The Plant Pathology Journal
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• v.19 no.1
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• pp.24-29
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• 2003

SS2-2, a hypernodulating soybean mutant was isolated by EMS mutagenesis from Sinpaldalkong 2. This auto-regulation mutant showed greater number of nodules and smaller plant size than its wild type Sinpaldalkong 2. SSR markers were used to identify DNA variation at SSR loci from different soybean LG. The only SSR marker that detected a length polymorphism between SS2-2 and its wild type ancestor was Satt294 on LG C1 instead of LG H, locating a hypernodulating gene. Sequencing data of flanking Satt294 indicated that the size variation was due to extra stretch of TTA repeats of the SSR motif in SS2-2, along with $A\longrightarrow$G transversion. In spite of phenotypic differences between the wild type and its hypernodulating mutants, genomic DNA poly-morphisms at microsatellite loci could not control regulation of nodule formation. The cDNA-AFLP method was applied to compare differential display of cDNA between Sinpaldalkong 2 and SS2-2. After isolation and sequence comparison with many AELP fragments, several interesting genes were identified. Northern blot analysis, immunolocalization and/or the yeast two-hybrid system with these genes might provide information on regulation of nodule development in SS2-2.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.749-758
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• 2023

An understanding of safety problems pursuant to environmental release of GM (Genetically Modified) crops is considered important. Among the recognized safety problems, the possibilities of weediness and ecosystem invasion are constantly being validated. We herein compared the growth characteristics and germination rate of soybeans formed by hybridization with vitamin A-enhanced soybeans carrying an introduced gene that increases β-carotene content. We also examined overwintering, survival, and weed competitiveness to evaluate hybrid ecological impact on long-term unmanaged cultivatable land. These studies revealed that the hybrid soybeans exhibited intermediate growth characteristics and germination rate compared with the vitamin A-enhanced soybeans and wild soybeans, or exhibited traits similar to those of the maternal strain. Overwintering experiments were conducted by planting seeds at depths of 0, 5, 10, and 20 cm and recovering them after three or five months. After five months, all seeds at depths more than 5 cm lost viability. Among seeds recovered after three months, only wild soybeans retained viability at depths of more than 5 cm. Survival and weed competitiveness were assessed by sowing each type of seed and performing no irrigation, or pest or weed control. Quantitative assessment of numbers of individual soybean plants that appeared in the experimental plot revealed that all plants germinated after sowing, but only wild type plants survived overwintering. These studies suggest that both GM soybeans and hybrid soybeans cannot survive in uncultivated land even if they are released into the environment, which indicates less possibility of ecosystem invasion and weediness.