• Korean Journal of Environmental Agriculture
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• v.26 no.3
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• pp.210-216
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• 2007

The cadmium (Cd) and zinc (Zn) contamination of soils and cultivated crop plants by zinc smelting activities was studied. In the study area of the vicinity of ${\triangle}{\triangle}$ zinc smelting factory in Korea, soils and corn plants were sampled at corn harvesting stage and analyzed Cd and Zn concentration as well as Cd and Zn fraction and chemical properties in soils. At 600 m radius of studied area, Cd and Zn were highly accumulated in the surface soils (0 - 20 cm) showed greater than the Korean warning criteria (Cd 1.5, Zn 300 mg $kg^{-1}$) with corresponding values 1.7 and 407 mg $kg^{-1}$, respectively. The leaf part gave higher Cd concentration with the corresponding value of 9.5 mg $kg^{-1}$ as compared to the stem and grains pare (1.6 and 0.18 mg $kg^{-1}$), respectively. Higher Zn concentration was also obtained from the leaf part of the corn plant which gave the value of 1,733 mg $kg^{-1}$. The stem and grain part gave corresponding values of 547 and 61 mg $kg^{-1}$. The order of the mean Cd concentration in fractions is F3 (oxidizable fraction) > F2 (reducible fraction) > F4 (residual fraction) > F1 (exchangeable + acidic fraction). A highly positive correlation is observed between F2 and concentration of Cd and Zn in both plant pare, leaf and grain. Highly positive correlations are shown in the pH exchangeable Ca and Mg, and CEC when correlated with Cd and Zn bound to F4 fractions. To reduce Cd and Zn uptake by corn plant in an arable land heavily contaminated with Cd and Zn as affected by smelting factory, an efficient and effective soil management to increase soil pH and CEC is thus recommended.

• Journal of The Korean Society of Grassland and Forage Science
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• v.8 no.1
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• pp.61-65
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• 1988

To examine the effects of light intensity on photosynthesis, corn and sorghum species were grown under shade cloths, which reduced light intensity by 25,50 and 75%. Photosynthetic rates were measured between 10 a.m. to noon on a clear day in early and mid - summer. 1. The degree of shading had a little effect on microenvironment. Air, soil and leaf temperatures were reduced as shade increased. 2. The degree of shading in early summer had relatively a little effect on photosynthesis of corn. However, the rates of photosynthesis in mid-summer decreased by 36%, 55% with relative light intensities of 50% and 25%, respectively. 3. The rate of photosynthesis was highly correlated with light intensity. The rates of photosynthesis with relative light intensities of 75,50 and 25% were decreased by 20, 40 and 5 4% in early summer, and by 17-53%, 36-64% and 5570% in mid-summer, respectively. 4. The 75% of light intensity had relatively little effect on dry matter yield of corn and sorghum species, however dry matter yield with 50 and 25% relative light intensities was decreased 17 and 36% in corn, 13-3 1 and 50-68% in sorghum species, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.1
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• pp.76-83
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• 1985

A hypothesis that artificial reforming of corn canopy could improve solar light penetration and dry matter production was tested in corn fields (var. Suwon 19) with three planting densities; low (60 ${\times}$ 40cm), medium (60 ${\times}$ 24cm) and high (60 ${\times}$ 16cm). Natural canopy was found that leaf orientations were even over all azimuth but somewhat inclined toward north-south direction and leaf angle ranged 38$^{\circ}$ to 71$^{\circ}$ from horizontal surface. Reforming corn canopy included following treatments: 1) natural canopy planted in north-south rows (natural canopy), 2)east-west plane canopy planted in north-south rows (E-W canopy), 3)east-west plane canopy and upright leaves in north-south rows, 4)north-south plane canopy (N-S canopy) in east-west rows. After corn plots were installed with training system by supporting poles and connecting wires, corn leaves were induced to a reforming direction and tied on wire. Average light intensity at the mid-point of plant height showed 5-10% increases in E-W canopy and in E-W canopy plus upright leaves, but a 2-10% decrease in N-S canopy from natural canopy. At yellow ripe stage, total dry wt. was increased in E-W canopy but not in N-S canopy. The E-W canopy produced 3-10% more grain yield than natural canopy. Though E-W canopy plus upright leaves yielded less at low density, it yielded up to 10% more at higher density. The N-S canopy yielded similar to low compared with natural canopy. These results suggests that reforming canopy toward solar incident direction increases light penetration into lower canopy, photosynthetic efficiency and grain yield, especially at high planting density in corn.

• The Korean Journal of Food And Nutrition
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• v.36 no.5
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• pp.395-402
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• 2023

As the consumption of corn increases, the production of by-products is also increasing. In this study, functional substances and antioxidant activities of corn by-products were investigated to determine their applicability as functional materials. Total polyphenol, flavonoid contents, and ABTS antioxidant activity were the highest in leaves. The total phenolic acid content was the highest in cobs; p-coumaric and ferulic acid were the main components. Phytosterol content in leaves and stems was high at 64 and 50 days after sowing, 261.4 and 274.7 mg/100 g, respectively. β-sitosterol of the leaves and stems was the highest, 149.2 and 138.7 mg/100 g. The total phytosterol content of grains and by-products harvested 106 days after sowing was in the order of: corn silk, husk, grain, leaf, stem, and cob. Among the phytosterols, β-sitosterol was the highest, followed by stigmasterol and campesterol, and the composition was different depending on part. The total phytosterol content was the highest in husk and corn silk, but the stems and leaves, which account for 50% of the total corn biomass, also contained high phytosterol content. Therefore, corn leaves and stems are expected to be used as functional raw materials for the development of functional materials in the future.

• Journal of Plant Biotechnology
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• v.30 no.2
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• pp.207-214
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• 2003

This study was carried out to establish a novel bioassay system for screening of compounds affecting aromatic amino acid or anthocyanin biosynthesis through investigating a degree of sucrose-induced anthocyanin formation such as size of plant material, buffer conditions, light intensity and irradiated duration, incubation temp., etc were determined and standard procedure (suitable experimental condition) was set up as follows. The second leaf blade of white corn seeding induced by fluridone treatment were segmented into a size of 5${\times}$5 min. The segments were floated on the solution of 1% sucrose in 1.0mM MES buffer (pH6.0∼6.5) and incubated at 26$^{\circ}C$ for 2days under the continuous light condition(70∼100$\mu$mol m$^{-2}$ s$^{-1}$ ). Anthocyanin in the purpled tissues was extracted with methanol containing 1% HCl and the optical density of the clear supematants was determined at 528mm. Influences of some chemicals were tested using this system. Glyphosate, 5-enolpyruvylshikimate 3-phosphate synthase inhibitor, showed most sensitive response with I$_{50}$ value at 3.3$\mu$M. Dicyclohexylcarbodiimide(DCCD) and parachloromercuribenzenesulfonic acid(PCMBS) had a relatively strong ingibition with I50 value at 7.1$\mu$M and 10.2$\mu$M, respectively. These results show that sucrose-induced anthocyanin formation in white com leaf segment provide a very simple and rapid system for searching new compounds affecting aromatic amino acid or anteocyanin biosynthesis by screening at less than 10$\mu$M.

• 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.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.1
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• pp.67-74
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• 1997

This experiment was conducted in 1992 and 1993 at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon to determine timing of rye(Secde cemde L.) harvest and residue chemical treatment prior to tillage in minimizing the adverse effects of the rye residue on growth and yield of succeeding corn(Zea muys L.). Eight treatments were established in 1993 which included four treatments such as no paraquat (1, l'diiethyl- 4, 4'-bipyridinium dichloride), paraquat treatment at 10, 23, and both 23 and 10 days prior to tillage when rye was harvested on April 14, and another four treatments such as no paraquat, paraquat treatment at 1, 5 and 10 days prior to tillage when rye was harvested on April 26. No paraquat treatment significantly resulted in reductions in corn plant height on June 3 and 10 when rye was harvested on April 14, but differences in the plant height and leaf number of corn among treatments were generally nonsignificant. Corn LA1 and silk emergence were not affected by paraquat treatment times regardless of rye harvested dates, but silk emergence was delayed by 1 to 2 days with no paraquat when rye harvested on April 14. Corn dry matter and TDN yields were significantly increased by paraquat treatment at 10 and 5 days prior to tillage treatment when rye was harvested on April 14 and 26, respectively, but other agronomic characteristics such as dry matter percentage, ear percent to total dry matter, and stover and ear yields of corn at harvest showed little or no response to paraquat treatment times.

• Journal of The Korean Society of Grassland and Forage Science
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• v.5 no.2
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• pp.143-151
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• 1985

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.3
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• pp.379-385
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• 1983

Forage productivity of Job's tears (Coix lachryma-jobi L.) and adlay (C. lachryma-jobi var. mayuen (ROMAN.) STAPF) and a hybrid corn (Kwangog) and sorghum-sudangrass hybrid (Pioneer 988) was compared in the southern part of Korea where black streaked dwarf virus' (BSDV) is prevalent. Emergence of Job's tears and adlay was more delayed compared to a corn or sorghum-sudangrass hybrid under the drought field conditions. Early growth and regrowth of Job's tears and adlay were less than those of sorghum-sudangrass hybrid. Fresh weight, dry weight, and digestible dry matter of Job's tears and adlay cut once approximately 40 days after flowering were much higher than those of two cuts at every flowering stage. Dry weight of one-cut Job's tears and ad lay harvested 40 days after flowering was similar to the total dry weight of three-cut sorghum-sudangrass hybrid but higher than that of silage corn. Digestible dry matter production was greater in the order of sorghum-sudangrass, corn, one-cut and two-cut Job's tears and adlay. Corn was severely infected with BSDV, but digestible dry matter was relatively high due to its higher in vitro dry matter digestibility. Among the Job's tears and adlay varieties, a variety of Job's tears with globular fruit shape was best for forage production due to its taller plant height, thick stem, wider leaf blades, higher leaf blade/total dry weight ratio, and higher forage yield. However, hulled grain yield of ad lay varieties was higher than that of Job's tears due to a higher hulled/rough grain ratio although they had similar rough grain yields.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.327-334
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• 2018

Northern corn leaf spot and southern corn leaf blight caused by Cochliobolus carbonum (anamorph, Bipolaris zeicola) and Cochliobolus heterostrophus (anamorph, Bipolaris maydis), respectively, are common maize diseases in Korea. Accurate detection of plant pathogens is necessary for effective disease management. Based on the polyketide synthase gene (PKS) of Cochliobolus carbonum and the nonribosomal peptide synthetase gene (NRPS) of Cochliobolus heterostrophus, primer pairs were designed for PCR to simultaneously detect the two fungal pathogens and were specific and sensitive enough to be used for duplex PCR analysis. This duplex PCR-based method was found to be effective for diagnosing simultaneous infections from the two Cochliobolus species that display similar morphological and mycological characteristics. With this method, it is possible to prevent infections in maize by detecting infected seeds or maize and discarding them. Besides saving time and effort, early diagnosis can help to prevent infections, establish comprehensive management systems, and secure healthy seeds.