• Journal of The Korean Society of Grassland and Forage Science
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• v.42 no.3
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• pp.162-168
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• 2022

This study was carried out to investigate the effects of planting densities on the growth characteristics, dry matter yield, and feed value of "Geukdong 6" (a new variety of corn for feed). The experimental design was arranged in a randomized block design with three replications. Treatments consisted of six planting densities, 60 cm × 25 cm (T1), 60 cm × 30 cm (T2), 70 cm × 25 cm (T3), 70 cm × 30 cm (T4), 80 cm × 25 cm (T5) and 80 cm × 30 cm (T6). All treatments were sown on May 14, 2021, and the harvest was on October 3 (late flowering). Plant length and the number of tillers were the highest in T5 (p<0.05), but the number of leaves and stem diameter were the highest in T6 than in the other treatments (p<0.05). Leaf length, leaf width, and dead leaf were not significantly different among the treatments. Organic matter was highest in T6, and crude protein was highest in T5 (p<0.05). The ether extract was not significantly different among the treatments. Crude fiber, NDF, and ADF were highest in T2 with relatively higher planting density (p<0.05). Calcium and phosphorus were not significantly different among the treatments. TDN content was the highest in T3 (p<0.05). Sugar degree (Brix), fructose, glucose, dextran, isomerose, and inverted sugar were not significantly different among the treatment. Fresh yield, dry matter yield and TDN yield were higher in order of T6 > T5 > T4 > T3 > T2 > T1 (p<0.05). Relatively feed value was higher in order of T3 > T6 > T5 > T1 > T4 > T2 (p<0.05). Based on the above results, planting density could be recommended from 80 cm × 30 cm for efficient production of "Geukdong 6".

• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.1
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• pp.1-5
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• 2013

Andaok, a new single cross variety, is a yellow dent maize hybrid (Zea mays L.) developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2011. This hybrid, which has a high yield of grain, was produced by crossing two inbred lines, KS161 and KS162. KS161 is the seed parent and KS162 is the pollen parent of Andaok. Silking date of Andaok is 3 days later than that of the check hybrid, Jangdaok. Plant height of Andaok is longer than that of Jangdaok. Ear numbers per 100 plants of Andaok is more than that of Jangdaok. Ear length of Andaok is shorter than that of Jangdaok. The weight of 100 seeds of Andaok is heavier than that of Jangdaok. It has moderate resistance to southern corn leaf blight (Bipolaris maydis), black streaked dwarf virus (BSDV) and corn borer. It has strong resistance to northern corn leaf blight (Exserohilum turcicum). It has resistance to lodging. Andaok was evaluated for its yield of grain at three locations from 2009 to 2011. The grain yield of Andaok was 7.80 ton/ha. Seed production of Andaok has gone well due to a good match during crossing between the seed parent, KS161, and the pollen parent, KS162, in Yeongwol.

• Korean Journal of Agricultural Science
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• v.4 no.1
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• pp.34-42
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• 1977

Three kinds of selection indexes were calculated and compared for effectiveness in selecting best performing hybrids from yield trial of corn. The following four characters were used in calculating indexes; yield, moisture content, and root and stalk lodging. 1. Among three indexes calculated, William's base index was more simple in calculation and more efficient in selection of a hybrid than other indexes. 2. Pesek and Baker's estimated index was considered less effective in this test, because of low estimation of genetic variance and covariances of characters from the limited materials and years of experiment. 3. Index calculated according to the Purdue University method (1976) was least effective, even though calculation was simple and easy. The less effectiveness of the index was due to the fact that equal importance of characters were given to each character without considering the differences in economic weight of each character. 4. Equations for expressing moisture content and root and stalk lodging in terms of market price were formulated and they were as follow : 1) Moisture content : $(Y-15.5){\times}$0.0065{\times}bushels/acre$, where Y was the average moisture content of a hybrid at the time harvest. The $0.0065 was the expenses required for removing one per cent of moisture from a bushel of shelled corn in 1976. 2) Root and stalk lodging:$Percent\;lodging{\times}price/Bu.{\div}50{\div}average$ yield of all entries in the test.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.310-313
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• 2009

A single cross, Pyeonganok, is an yellow flint-like maize hybrid (Zea mays L.) developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2008. This hybrid, which has a high yield of dry matter was produced by crossing two inbred lines, KS140 and KS94. KS140 is the seed parent and KS94 is the pollen parent of Pyeonganok. Silking date of Pyeonganok is 3 days later than that of check hybrid, Kwangpyeongok. Stay-green of Pyeonganok is not greatly different with that of Kwangpyeongok. It has resistance to lodging. It has moderately resistance to Bipolaris maydis (southern corn leaf blight), Exserohilum turcicum (northern corn leaf blight), and corn borer but sensitivity to black streaked dwarf virus (BSDV). Pyeonganok was evaluated for the yields of dry matter at four locations from 2006 to 2008. The yields of Pyeonganok in dry matter was 20.84 ton/ha. Seed production of Pyeonganok has gone well due to a good match during crossing between the seed parent, KS140 and the pollen parent, KS94 in Yeongwol.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.130-137
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• 2021

This study evaluated newly introduced, commercial super sweet corn hybrids (Zea mays L.) for their potential as breeding materials. Agronomic traits were measured and variance components were obtained using a linear mixed model to estimate the heritability. The trials were carried out in 2018 at two locations (Haenam and Oksan in South Korea). All traits had low heritability, except for mid tasseling and silking days. These traits with low heritability mostly had low genetic variance component estimate. In case of ear height ratio, significant genotype by location appeared to be responsible for low genetic variance, which in turn led to low heritability. Low heritability estimates from the trials with commercial hybrids were perhaps because those hybrids were highly improved for commercial success. Hence, this does not necessarily point to them having poor potential as breeding materials. To overcome low heritability, significant genotype by environment interaction, and achieve high selection efficiency, intermating among hybrids is recommended to create new recombinants before inbred line development.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.98-105
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• 2020

This experiment was conducted to a comparison of the productivity according to variety and forage quality by plant parts of imported silage corn (Zea mays, L) in Pyeongchang. The corns evaluated in this experiment were 8 varieties (P1184, P1151, P1194, P1543, P1345, P1429, P1443, and P2105) introduced from the United States, Pioneer Hybrid Co. The harvested corn was divided into 5 plant parts (leaf, stem, cob, husk, and grain), and the ratio of each part was calculated using dry weight and the feed value was analyzed. The emergence rate of corn was generally good except for the P1151 and P2105 varieties. The average tasseling date was July 24^th and the silking date was July 27^th, but the P2105 variety was late to July 28^th and August 1^st, and the remaining varieties were similar. P1345 was the highest (289 and 123 cm), and P1151 varieties were the lowest (267 and 101 cm) in the plant and ear height. Disease resistance was low in P1184, P1443 and P1429, and P1197 and P1345 were high. In the case of stover, the dry matter (DM) content was the lowest at 19.6% in the P1151 and the highest at 24.9% in the P1429. DM content of ear was the highest in the P2105 (55.5%), and P1184 (54.2%) and P1345 (54.3%) were also significantly higher (p<0.05). The DM yield of stover of P2105, P1429 and P1194 varieties was significantly higher (p<0.05), and ear yield of P2105, P1345 and P1443 was higher. The proportions of each part of plants (leaf, stem, cob, husk, and grain) divided by 5 was high, with 50-60% of the ear(grain+cob) ratio. The ratio of husk and cob was roughly similar, and the leaf and stem part showed a ratio of about 20%. The crude protein (CP) content was highest in leaf, followed by grain. The CP content of the stem was the lowest, and the husk was not significantly different among the varieties (p>0.05). The acid detergent fiber (ADF) content was similar to the rest parts except grain, but the leaf part tended to be lower, and other parts except the stem and leaf showed no significant difference between varieties (p>0.05). There was no significant difference in NDF (neutral detergent fiber) content in husk, but there was a difference between varieties in other parts (p<0.05). In addition, there was a special difference by plant parts for each variety, P2015 on the stem, P1197 on the leaf, P1151 on the cob, P1197 on the husk, and P1197 on the grains with high NDF content. IVDMD (in vitro dry matter digestibility) was not significantly different between stems and grains, but there was a difference between varieties in cobs and husks. According to the results, DM yield of P2105 variety was the best in the experiment, and the ratio of grain was excellent in P1543 and P1345. In addition, it was found that the feed value was higher in the leaves and grains, and the leaf and stem had higher feed values than husk or cob.

• Korean Journal of Weed Science
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• v.15 no.1
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• pp.85-98
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• 1995

Six malformin B's produced by Aspergillus niger van Tiegh. were separated by HPLC. Their structures determined by the methods of amino acid analyses, mass spectrometry, and two-dimensional NMR were revealed as cyclic pentapeptides structurally related to malformin $A_1$. Both the NMR and MS/MS data suggest that the respective structures of separated malformin B's were as follows; cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-allo-Ile for $B_{1a}$, cyclo-D-Cys-D-Cys-L-Val-D-Leu-L-Leu for $B_{1b}$, cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Leu for $B_2$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Leu for $B_3$, cyclo-D-Cys-D-Cys-L-Val-D-Ile-L-Ile for $B_4$, and cyclo-D-Cys-D-Cys-L-Val-D-Val-L-Ile for $B_5$. Among the malformin B's, the structure of $B_{1b}$ was the same as that of malformin $A_3$ or C. All the malformin B's showed physiological activities in the two assay systems using corn(Zea mays L.) roots and mung bean(Phaseolus aureus Roxb.) hypercotyl segments. The malformin B's with molecular weight 529 were more effective for inducing corn root curvature than those with molecular weight 515. The difference in molecular weight of malformin B's, i.e., the retention time on HPLC, results in the polarity change of the whole malformin molecule which affects the revealation of the malformin activities. In addition, the disulfide form of the malformin B's gives the rigidity of the molecule, whereas the combination of the fourth and the fifth amino acid residues provides the optimal three-dimensional configuration to the malformin receptor of plants. Presumably, these two factors are appeared to be essential for the greatest physiological activity of malformin B's. malformin $B_{1a}$ caused the corn root curvature by 90% at a concentration of $0.25{\mu}M$. However, such differential activities with molecular weight of 529 or 515 of malformin B's were not found in the mung bean hypercotyl segment test. Maximum stimulation of mung bean hypercotyl growth was observed at $0.1{\mu}M$ concentration of malformin B's. The growth of the segments treated with $B_5$ was 154% greater than that of the control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.392-401
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• 2023

Corn (Zea mays L.) is one of the world's most important crops, along with wheat and rice, with a global corn production expected to reach 1,154.5 million tons in 2023. Considering this grain production, The generation of corn cob is expected to reach approximately 207.8 million tons in 2023. However, as an agricultural by-product, corn cobs are often considered waste and remain underutilized. Phytosterols, which are abundant in vegetable oils such as corn oil, provide a number of health benefits, including liver health, cholesterol reduction, and protection against chronic diseases such as diabetes. In this study, we investigated the potential of Kwangpyeongok ears, which are commonly used as grain and silage corn in Korea. We also examined the variation in phytosterol content with the maturity of corn ears to identify the optimal time for utilization. At the beginning of physiological maturity, corn cobs had 113.3 mg/100g DW of total phytosterols, which was highest phytosterol abundance during the growth stage. Corn kernels also had the highest phytosterol content at the beginning of physiological maturity. While previous studies on corn bioactive compounds have mainly focused on the kernels, the results of this study highlight that cobs are an excellent source of these compounds. Furthermore, phytosterol levels were influenced by genetic factors and developmental stages, suggesting the to increase the use of cobs as a source of bioactive compounds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.392-402
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• 2021

The present study investigated the effects of tillage practices (deep cultivation [DC] and conventional tillage [CT]) and extended planting dates (mid-June to July) for maize-onion rotation in paddy fields. The silage corn (Zea mays L.) cultivar 'Kwangpyeongok' and the waxy corn cultivar 'Ilmichal' were planted on June 14, July 3, and July 15 in 2019. In both maize, the plant height of June 14 planted was up to 100 cm greater than that of July 15 planted on August 16 and up to 40 cm on August 30. At 30 Days after planting, the leaf area index (LAI) of silage corn planted on July 3 and 15 greater than that of corn planted on June 14 due to high temperature in the early season; however, there were no differences in the LAI of waxy corn according to the planting date. Despite favorable temperature, plants sown on July 3 and 15 experienced high moisture stress during the seedling stage due to consistent rainfall, and waxy corn was highly sensitive to high moisture stress. The total yield of silage corn was 1,232 (845 in TDN), 860 (598 in TDN), and 765 (508 in TDN) DW kg·10a^-1 for plants sown on June 14, July 3, and July 15, respectively. The fresh marketable ear yield of waxy corn was 872, 814, and 525 FW kg·10a^-1 for plants sown on June 14, July 3, and July 15, respectively. After the completion of maize cultivation, onion seedlings (Allium cepa L.) were transplanted on November 12, 2019, and harvested on May 27, 2020. Neither summer tillage nor maize planting date affected onion growth or yield. The marketable onion yield was 8,305 and 7,848 kg·10a^-1 with DC and CT, respectively. In conclusion, DC did not improve maize growth or yield under paddy conditions. Mid-June to early July is a practical window for maize planting for growers in this region.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.140-145
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• 1985

Field experiments were conducted in Suwon in 1982 and 1983 to evaluate the effects of compost application, nitrogen (N) rate and split application of N on growth, yield and N uptake of sweet corn (Zea mays L.) grown under clear polyethylene mulching condition. Urea was banded at N rates of 0 (only in 1983), 5, 10, 15 and 20 kg per 10a with or without compost application of 1500 kg per 10a at planting. In 1982, half of N was sidedressed at the 5-6 leaf stage in case of 15, and 20 kg N per 10a. Compost application increased ear size and ear weight per 10a (10%). The number of ears per 10a markedly increased with an increase in N rates up to 10 kg per 10a but was not significantly affected by further increased N rates. Ear weight per 10a increased linearly as N rate increased from 0 to 20 kg per 10a without compost but increased greatly up to 10 kg N per 10a with compost application. Dry matter yield increased greatly up to 15, 10 kg N per 10a with and without compost application, respectively. Nitrogen uptake increased linearly from 8.1 to 18.8 kg per 10a with an increase in N rates from 0 to 20 kg per 10a. The optimum N rate appeared to be 10 to 15 kg per 10a based on ear number, ear weight and dry weight per 10a. There was no significant difference between basal and split applications of N in terms of ear size, and number and weight of ears per 10a.