• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.278-286
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• 2019

Sesbania, an annual herb, is known for its high forage value and salt tolerance. It has merits as a forage crop that is adaptable to reclaimed land in the Republic of Korea. Therefore, we collected Sesbania genetic resources from the Republic of Korea and other countries, and conducted experiments to evaluate their potential as a forage crop in Korean climate and soil conditions. In the preliminary experiments, 15 genetic resources which were able to set seeds in Korean environment were selected out of a total of 46 collected genetic resources. Among 15 genetic resources, SL13 was the tallest and it was followed by that of SC04, SR01 and SE07. The accessions with the earliest flowering started flowering 101 days after sowing and set seed in early August. Fifteen accessions were evaluated for their salt tolerance at germination stage based on germination rate and growth of germinated seedlings at 0 mM, 150 mM and 300 mM NaCl concentrations. Five genetic resources like SC04, SL13, SS20, SS24 and SR01 were selected to be tolerant to NaCl treatment. Forage value was evaluated based on crude protein, acid detergent fiber, neutral detergent fiber and in vitro dry matter digestibility. The forage value of leaves was significantly higher than that of stems, and the forage value of the stem was slightly better than that of rice straw. The forage value of leaves of all the genetic resources was higher than grade 1 by the American Forage and Grassland Council grade. Among five selected genetic resources, the relative feed value of SC04 was the highest and it was followed by that of SS20, SL13, SS24 and SR01.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.419-427
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• 2021

In South Korea, direct seeding of rapeseed (Brassica napus L.) is difficult during spring cultivation in early March because of the low yield production associated with late flowering and poor seed quality. To compare the period of direct sowing, the present study investigated the growth characteristics of rapeseed according to planting dates. Specifically, 35 day-old seedlings were transplanted or directly sown on four different dates (late February, early March, late March, and early April) in 2020 and 2021. As the planting date was delayed, the days to flowering of rapeseed decreased. Similarly, the plant height, seed set percentage, and seed yield of rapeseed were reduced upon delay in planting. The seed yield of rapeseed through direct seeding in late February was the highest, 2.76 ton·ha^-1. On all seeding dates, except for late February, the transplanted rapeseed produced a higher yields than the directly seeded rapeseed. The crude oil and oleic acid content, which is related to the quality of rapeseed, decreased with the delay in planting dates, and this decrease was greater, with the direct seeding of rapeseed depending on the sowing time. In the correlation analysis, the planting date was significantly and negatively correlated with the yield, crude oil content, and oleic acid content of the transplanted rapeseed, while the sowing date was negatively correlated with the plant height, silique size, yield, and seed quality of the directly seeded rapeseed. Finally, the effect of planting date on rapeseed growth was stronger in direct seeding than in transplanting. Therefore, during spring cultivation after late February to early March, transplanting, rather than direct seeding, in more advantageous in terms of seed quality and yield.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.385-393
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• 2011

Soybean is the most promising crop for substituting rice on the paddy field. Excessive water stress is a common limiting factor in soybean yield under paddy soil condition. This study was carried out to identify changes in leaf total nitrogen and petiole ureide content under excess water conditions for establishing a screening system related to waterlogging tolerance. Waterlogging treatment was conducted by maintaining the water level on the soil surface for 10 days at the early vegetative growth stage ($V_5$) and the flowering stage ($R_2$). Leaf total nitrogen content, SPAD value and ureide content in petiole decreased in all soybean varieties in response to waterlogging, but the degree of decrease was much lesser in Pungsannamulkong and Muhankong than in Jangyeobkong and Myungjunamulkong, at 21 days after waterlogging treatment. This result means that root and nodule recovery rates were much higher in Pungsannamulkong and Muhankong than in Jangyeobkong and Myungjunamulkong after waterlogging treatment. The ureide and leaf nitrogen content showed high positive correlation with SPAD value, regardless of waterlogged stages. In conclusion, leaf nitrogen content, ureide content in petiole and leaf greenness were identified as promising indicator for screening soybeans which are tolerant of excess water.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.61 no.2
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• pp.79-86
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• 2016

The late-maturing black rice cultivar Shinnongheugchal from Jeollabuk-do Agricultural Research and Extension Service was used as the plant material for estimating growth characters, quality and yield from the vegetation period to harvest age. This study was performed to select an optimum combination of nitrogen level and planting density for the maximum yield of Shinnongheugchal. The plant height, number of tillers, and SPAD index were higher when the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level was used at 30 days after transplanting. The heading date for the combination of 70 hills per $3.3m^2$ and 15 kg/10 a nitrogen level, and 80 hills per $3.3m^2$ and 15 kg/10 a nitrogen level was August 22. The heading date for the other combinations was August 21. The combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level yielded the highest number of tillers at 40 days after flowering. Even though the lodging index was increased with increasing nitrogen levels, field lodging did not occur until harvest time. Seed nitrogen concentration in the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level showed a significant difference when compared with the other combinations. The black rice yield varied significantly, and the highest yield was observed in the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level. The yield was significantly correlated with seed nitrogen concentration. The maximum yield was estimated to be 14.67 kg/10 a nitrogen level by using the regression equation. On average, the coloring degree of the black rice was higher at planting density of 70 hills per $3.3m^2$ than at 80 hills per $3.3m^2$. The highest yield of perfect black rice was obtained using the combination of 70 hills per $3.3m^2$ and 13 kg/10 a nitrogen level. Our findings demonstrate that a nitrogen level of 13-14 kg/10 a can be used to obtain the maximum yield from Shinnongheugchal with yield, cyanidin 3-glucoside content, and perfect black rice yield as the standard.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.384-394
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• 2019

We have investigated the effects of ambient temperature on the growth of wheat in Korea. The differences in the growth phase of wheat were compared according to the temperature treatment. The productive tiller number and dry weight were decreased in a plot under a higher temperature treatment. We found that the growth of Jinpum was different from that of the alternative wheat cultivars, which were bred in Korea, at 50 days after treatment. While the Jinpum wheat grown at 17℃ showed vegetative stage growth, that grown in the 23℃ growth chamber entered the heading and flowering stage. The differences in the expression of 16 genes known to be involved in high-temperature responses were checked by using Jinpum wheat 50 days after two temperature treatments (17℃ and 23℃), which showed apparent differences in expression between the higher and lower temperatures during the growth phase. In the 23℃ treatment samples, the genes with increased expression were HSP70, HSP101, VRN2, ERF1, TAA1, YUCCA2, GolS, MYB73, and Histone H2A, while the genes with decreased expression were VRN-A1, DREB2A, HsfA3, PIF4, PhyB, HSP17.6CII, rbcL, and MYB73. YUCCA2, HSP101, ERF1, and VRN-A1 showed a significant difference in gene expression between lower- and higher-temperature conditions. Overall, combining the means of the expression of various genes involved in thermosensing, vernalization, and abiotic stresses, it is possible to conclude that different sets of genes are involved in vernalization and summer depression of wheat under long term, high ambient temperature conditions.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.266-270
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• 2010

Corylopsis coreana is an endangered Korean native plants. This is one of the genus that have high ornamental value for flowering plants available for garden shrub, bonsai, and pot plants. In this study, the methods to encourage seed germination rate were investigated for its ornamental uses. The germination rate of Corylopsis coreana seeds stored under dry-cold condition was very low, 12%, 12%, 8%, and 10%after 40, 70, 85, and 100 days storage respectively. But the germination rate of Corylopsis coreana seeds stored under wet-cold condition was higher than these, 20%, 54%, 78%, and 96% after 40, 70, 85, and 100 days storage respectively. Dry seeds sowed directly without $GA_3$ treatment showed no germination regardless of storage type(cold or room temp.) or storage periods. On the other hand, the soaking treatment with $GA_3$ 50~500 ppm for 24 hours was very effective to increase the germination rate. The most effective $GA_3$ levels was different by storage type(cold or room temp.) and storage periods. But the effect of $GA_3$ was decreased by prolonging of the storage period. Soaking treatment with $Ca(NO_3)_2$ 5, 10, 20 mM, $KNO_3$ 5, 10, 20 mM for 24 hours showed no effect.

• Korean Journal of Soil Science and Fertilizer
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• v.22 no.4
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• pp.329-336
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• 1989

A series of green house experiment was conducted to find but the effect of fertilizer application and inoculation of rhizobium on the changes of amide-N, ureide-N and $NH_4-N$ concentration in stem and root exudates of soybean plant growth. The results obtained were summarized as follows ; 1. Five strains of indigenous Rhizobium japonicum-nitrogen fixing activity($C_2H_2$-reducing activity) was more than 6.4 to 20.1 nmole/hr/tube-were identified from 37 soil samples in 22 areas of farmers field throughout country. 2. These identified 5 strains of rhizobium were obtained high nitrate reductase but low ammonium and nitrite oxidase activities. Among 5 strains of rhizobium the Rhizobium japonicum RjK-134 was applied for this green house experiment. 3. Dry matter yield was increased by the combination of inoculation of Rhizobium japonicum RjK-134 with no fertilizer and without nitrogen fertilizer application. However, dry matter yield was decreased with application of N and NPK with inoculation of rhizobium. 4. The concentrations of amide-N and ureide-N were increased in xylem sap than that of root exudate and higher concentration was obtained ar 30 days after planting than flowering stage (45 days after planting). 5. The combination of NPK application with inoculation of Rhrizobium japonicum RjK-134 enhanced the increase of amide-N and ureide-N concentration in xylem sap and root exudate. 6. High ammonium-N concentration in xylem sap and root exudate were obtained in combination with without-fertilizer under no inoculation of rhizobium and N and NPK application with inoculation of rhizobium.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.182-191
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• 2020

A field test and a phytotron study were performed over two years to examine whether rice varieties originated from higher altitude areas have lower optimum grain filling temperatures for yield improvement than the varieties from South Korea. Three varieties originated from North Korea and three varieties from northern China were compared to the same number of varieties from South Korea. In a field study, the optimum grain filling temperatures over 40 days after heading were 22.6 - 23.0℃, 21.5 - 22.3℃, and 21.5 - 23.6℃ for the varieties from North Korea, northern China, and South Korea, respectively, resulting in no significant difference among varietal groups. Meanwhile, the heading dates of the early maturing varieties from North Korea and China were 7 - 12 days earlier than that of the early maturing Odae variety from South Korea during the first transplant of 2017. The phytotron study, in which different temperature regimes were imposed from flowering/fertilization to harvest with constant daily mean temperatures, revealed that milled rice weight did not decrease under low temperatures, even at 16℃, compared to that at 22℃. At the fourth transplant in the field study, mean temperature lower than 10℃ appeared before rice grains were fully developed, resulting in yield reductions. It was concluded that rice varieties adaptable to high-altitude areas do not have lower optimum grain filling temperatures but, instead, possess shorter growth durations. It was further suggested that the optimum grain filling temperature of rice observed under natural conditions could be attributed to the lowering temperature at the late filling stage under temperate climatic conditions.

• Journal of Korean Society of Forest Science
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• v.21 no.1
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• pp.1-34
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• 1974

The author intended to investigate external and internal changes in the cone structure, changes in water content, sugar, fat and protein during the period of seed maturation which bears a proper germinability. The experimental results can be summarized as in the following. 1. Male flowers 1) Pollen-mother cells occur as a mass from late in April to early in May, and form pollen tetrads through meiosis early and middle of May. Pollen with simple nucleus reach maturity late in May. 2) Stamen number of a male flower is almost same as the scale number of cone and is 69-102 stamens. One stamen includes 5800-7300 pollen. 3) The shape is round and elliptical, both of a pollen has air-sac with $80-91{\mu}$ in length, and has cuticlar exine and cellulose intine. 4) Pollen germinate in 68 hours at $25^{\circ}C$ with distilled water of pH 6.0, 2% sugar and 0.8% agar. 2. Female flowers 1) Ovuliferous scales grow rapidly in late April, and differentiation of ovules begins early in May. Embryo-sac-mother cells produce pollen tetrads through meiosis in the middle of May, and flower in late May. 2) The pollinated female flowers show repeated divisions of embryo-sac nucleus, and a great number of free nuclei form a mass for overwintering. Morphogenesis of isolation in the mass structure takes place from the middle of March, and that forms albuminous bodies of aivealus in early May. 3. Formation of pollinators and embryos. 1) Archegonia produce archegonial initial cells in the middle and late April, and pollinators are produced in the late April and late in early May. 2) After pollination, Oespore nuclei are seen to divide in the late May forming a layer of suspensor from the diaphragm in early June and in the middle of June. Thus this happens to show 4 pro-embryos. The organ of embryos begins to differentiate 1 pro-embryo and reachs perfect maturation in late August. 4. The growth of cones 1) In the year of flowering, strobiles grow during the period from the middle of June to the middle of July, and do not grow after the middle of August. Strobiles grow 1.6 times more in length 3.3 times short in diameter and about 22 times more weight than those of female flower in the year of flowering. 2) The cones at the adult stage grow 7 times longer in diameter, 12-15 times shorter diameter than those of strobiles after flowering. 3) Cone has 96-133 scales with the ratio of scale to be 69-80% and the length of cone is 11-13cm. Diameter is 5-8cm with 160-190g weight, and the seed number of it is 90-150 having empty seed ratio of 8-15%. 5. Formation of seed-coats 1) The layers of outer seed-coat become most for the width of $703{\mu}$ in the middle of July. At the adult stage of seed, it becomes $550-580{\mu}$ in size by decreasing moisture content. Then a horny and the cortical tissue of outer coats become differentiated. 2) The outer seed-coat of mature seeds forms epidermal cells of 3-4 layers and the stone cells of 16-21 layers. The interior part of it becomes parenchyma layer of 1 or 2 rows. 3) Inner seed-coat is formed 2 months earlier than the outer seed-coat in the middle of May, having the most width of inner seed-coat $667{\mu}$. At the adult stage it loses to $80-90{\mu}$. 6. Change in moisture content After pollination moisture content becomes gradually increased at the top in the early June and becomes markedly decreased in the middle of August. At the adult stage it shows 43~48% in cone, 23~25% in the outer seed-coat, 32~37% in the inner seed-coat, 23~26% in the inner seed-coat and endosperm and embryo, 21~24% in the embryo and endosperm, 36~40% in the embryos. 7. The content compositions of seed 1) Fat contents become gradually increased after the early May, at the adult stage it occupies 65~85% more fat than walnut and palm. Embryo includes 78.8% fat, and 57.0% fat in endosperm. 2) Sugar content after pollination becomes greatly increased as in the case of reducing sugar, while non-reducing sugar becomes increased in the early June. 3) Crude protein content becomes gradually increased after the early May, and at the adult stage it becomes 48.8%. Endosperm is made up with more protein than embryo. 8. The test of germination The collected optimum period of Pinus koraiensis seeds at an adequate maturity was collected in the early September, and used for the germination test of reduction-method and embryo culture. Seeds were taken at the interval of 7 days from the middle of July to the middle of September for the germination test at germination apparatus.

• The Korean Journal of Pesticide Science
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• v.18 no.1
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• pp.33-40
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• 2014

To control Bemisia tabaci on tomato, we applied five different combinations of chemical treatments as below: 1) treatment of combinations of cyantraniliprole on the root area and leaf with the existing registered chemicals three times; 2) treatment of combinations of cyantraniliprole on the root area and dinotefuran + emamectin benzoate on the leaf with the existing registered chemicals three times; 3) treatment of combinations of dinotefuran on the root area and cyantraniliprole on the leaf with the existing registered chemicals three times; 4) treatment of combinations of dinotefuran on the root area and dinotefuran + emamectin benzoate on the leaf with the existing registered chemicals three times; 5) untreated control plot (Table 1). Twenty days after treatment ($17^{th}$ Aug.), the number of population of B. tabaci was zero on the 1, 2, 3, 4 treatments of combinations, and only 2 individuals were found on the 5 treatment of combination per each 20 plant. On $17^{th}$ Sep., in the last observation, the average number of population of B. tabaci was 10.3, 10.3, 10.6 on the 1, 2, 3 treatments of combinations on the 20 plants per each combination, however, the average number of 23.3 and 37.6 were examined on the 4 and 5 treatments of combinations, respectively. TYLCV was not occurring on the 1 and 2 treatments of combinations, and presented only 3% and 17% on the 3 and 4 treatments of combinations, respectively, which indicates that the treatments (1-4) should be effective on TYLCV control as considering that 33% of TYLCV occurred on the untreated control plot. However, after the third flowering period, there is no difference among the five combinations. The amount of products was 9,148g and 9,698g on the 1 and 2 treatments of combinations, respectively, which was the most among the 5 combinations. The number of fallen fruits and the average weight of fruits showed the similar tendency.