• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.37-43
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• 2020

This study was conducted to evaluate the effects of different nitrogen levels on the yield and nutrient quality of a newly developed domestic hybrid of Teosinte, Geukdong 6〔Zea mays L. subsp. mexicana (Schrad.) H. H. Iltis〕. The field experiment was conducted in a randomized block design with three replicates and consisted of four nitrogen (N) application rates, T1 (200 kg/ha), T2 (300 kg/ha), T3 (400 kg/ha), and T4 (500 kg/ha). No differences were found in plant length, leaf length, leaf width, leaf number, dead leaves, stem hardness, tiller number, and fresh yield (p>0.05). The T3 showed significantly greater dry matter yield at harvest (heading stage) compared to the other treatments (p<0.05). The crude protein content of T4 (10.49%) was higher than those of T1 and T2 (p<0.05). However, there was no significant difference between T4 (10.49%) and T3 (9.63%). The effects on crude fat, crude ash, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude fiber were not significant (p>0.05). The sugar content was higher in the T2 treatment than the other treatments (p<0.05). For Ca, T3 showed significantly greater content (p<0.05). However, no significant effects were found in the contents of Cu, Fe, K, Mg, Mn, Mo, and Zn (p>0.05). Na content was higher in order of T2 > T4 > T3 > T1 (p<0.05). Total mineral contents were not significantly different among the treatments (p>0.05). Given these results, we recommend the amount of nitrogen fertilization necessary for "Geukdong 6" to be around 400 kg per ha (T3), when considering, high fresh yield, dry matter yield, number of leaves and content of crude protein.

• Journal of The Korean Society of Grassland and Forage Science
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• v.12 no.3
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• pp.193-200
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• 1992

This study was carried out to determine the optimum fertilizer level of phosphate for maximum yield of soiling cowpea(Vigna sinensis Endlicher) in Cheju. The results obtained are summarized as follows:1. Plant length, fresh yield, stem and leaf weight per plant, node number of main stem, primary branch number per plant, pod number per plant and pod weight per plant increased with increasing of phosphate level regardless of growth stage.2. Plant length and node number of main stem did not increase after August 25, 40 days after planting. Leaf weight and fresh yield were greatest on August 25, and then reduced. 3. Stem weight the number of leaves and pods and pod weight per plant increased until September 13, 80 days after planting. 4. Increased level of phosphate delayed leaf weight decrease after August 25. 5. Root length and root weight per plant increased with increasing level of phosphate regardless of growth stage, and they did not increase after Augest 25. 6. Nodule number and nodule weight per plant also increased as phosphate rate increased regardlessof growth stage. Nodule number and nodule weight were greatest on August 5, and then rapidly decreased.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.39-40
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• 2001

This experiment was conducted to investigate the effect of root zone heating on the growth of cut minirose Rosa hybrida L. ′Little Marble′ in winter season. Effects of four different root zone temperatures of 16, 20, 24$^{\circ}C$ and non-heating control on the growth and productivity were compared. Harvested cut-flowers were measured for stem length, stem diameter, fresh and dry weights, numbers of leaves, stems and flowers, days to flower, and chlorophyll concentration. The results showed that mean height was the greatest at 16$^{\circ}C$. Days to flower was the shortest at 24$^{\circ}C$. Fresh and dry weights of top (shoot＋leaf＋flower), shoot and leaf were the greatest at 2$0^{\circ}C$. Stem and flower numbers were the greatest at 16$^{\circ}C$, but leaf number was the greatest at 2$0^{\circ}C$. Mean cut flower yield was the greatest at 16$^{\circ}C$. Chlorophyll concentration was slightly higher at 16$^{\circ}C$, but was not significantly different among the treatments. Stem diameter was the greatest at 2$0^{\circ}C$. Dry matter was the greatest at 24$^{\circ}C$. Total yield of cut rose stems increased with increasing temperature. Combined heating could save 24% in fuel cost as compared to the air heating alone. The results obtained suggested that optimal root zone temperature for the growth of cut rose "Little Marble" was 2$0^{\circ}C$, and the greenhouse heating energy can be saved by minimal air heating combined with root zone heating to 2$0^{\circ}C$.

• Research in Plant Disease
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• v.29 no.2
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• pp.137-144
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• 2023

Exserohilum turcicum is a fungus that causes northern corn leaf blight (NCLB) and has deleterious effects on maize production globally. Therefore, it is prudent to mitigate the effects of NCLB using genetic diversity. The objective of this research was to assess the severity of NCLB disease on the growth and yield of various maize genotypes. A randomized complete block design field experiment, replicated three times, was conducted to evaluate the effect of E. turcicum on 10 maize hybrids. Percent disease index, plant height, and leaf area were recorded at the silk stage. Cob weight, grain fresh weight, and grain yields were determined at harvest maturity. All measured parameters were significantly different (P<0.05) between the maize hybrids. Of the 10 genotypes, four (PAN 4R-528R, PAN 4R-728BR, PAN 3R-724BR, and P1788BR) were susceptible, five (DKC74-74BR, PAN 5R-582R, PAN 5R-890R, PAN 5R-854R, and PAN 5R-590R) were moderately susceptible, and one (DKC80-40BR) was moderately resistant. DKC80-40BR exhibited greater cob weight, while DKC74-74BR was superior in all other plant growth and yield components. Interestingly, although not significant (P>0.05) and high, maize growth and yield parameters had negative correlations with disease incidence, except for grain fresh weight. Therefore, DKC80-40BR may be selected for cultivation in areas prone to NCLB to reduce maize susceptibility to the disease, while DKC74-74BR may improve crop performance. These hybrids could be considered as potential sources of resistance or tolerance to NCLB for further validation by plant breeders.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.35-43
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• 2012

The objective of this research was to confirm the difference in physiological responses to environmental stresses such as chilling, high temperature, NaCl, and chemical stress (paraquat) in Protox inhibitor resistant-transgenic rice (MX, PX, and AP37) and its non-transgenic counterpart (WT). Transgenic and non-transgenic rice plants were exposed to a chilling temperature of $5^{\circ}C$ for 1 day or a high temperature of $45^{\circ}C$ for 4 days and allowed to recover at $25^{\circ}C$ for 6 days after the chilling treatment or 8 days after the high temperature treatment. Leaf injury, shoot fresh weight, porphyrin biosynthesis substances, and chlorophyll content were investigated in transgenic and non-transgenic rice at 6 days after 0.5% and 1% NaCl treatments or at 5 days after 0~300 ${\mu}M$ paraquat treatments. No significant difference in leaf injury and shoot fresh weight were observed between transgenic and non-transgenic rice during chilling and recovery. Plant height and shoot fresh weight were also similar between transgenic and non-transgenic rice during the high temperature and recovery period (0~5 days). However, plant height and shoot fresh weight in transgenic rice line MX and PX were lower than in non-transgenic rice at 6 days for recovery. Leaf injury, chlorophyll, and Mg-Proto IX ME contents had no significant difference between transgenic rice and non-transgenic rice after NaCl treatment, but Proto IX content for AP37 and shoot fresh weight for PX and AP37 in 0.5% NaCl treatment were significantly reduced compared with non-transgenic rice. There was no difference in leaf injury and shoot fresh weight when comparing transgenic rice and non-transgenic rice after paraquat treatment. Although transgenic rice and non-transgenic rice showed a little difference at a particular measurement period in certain environmental stresses, there was generally no difference in physiological responses between transgenic rice and non-transgenic rice.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.744-748
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• 2000

The characteristics of $CO_2$ exchange between plant and human modules, absorption rate of NO$_2$, and growth of lettuce were examined in an urban-type plant factory(UPF). With 150 lettuce plants, $CO_2$ concentrations of plant module were 600 ~ 700$\mu$mol mol$^{-1}$ at average leaf weight of 130g.plant$^{-1}$ and 900~1100$\mu$mol.mol$^{-1}$ at 75g.plant$^{-1}$ for one and two persons' stay in the human module, respectively. When the air of 0.13, 0.30 and 0.45 $\mu$molㆍmol$^{-1}$ NO$_2$ in a human module was circulated ON/OFF 10/20min between the human and plant modules, $NO_2$ decrement in the chamber during 10 min was 0.040, 0.109, and 0.149 $\mu$mol, respectively. The lettuces grown at 0.45 $\mu$molㆍmol$^{-1}$ $NO_2$ during experimental period showed no significant differences in growth factors such as leaf width, leaf length, leaf area and fresh weigh, and in the quality between treated and control.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.5
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• pp.394-406
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• 2004

A split-plot designed experiment including four rice varieties and 10 nitrogen levels was conducted in 2003 at the Experimental Farm of Seoul National University, Suwon, Korea. Before heading, hyperspectral canopy reflectance (300-1100nm with 1.55nm step) and nine crop variables such as shoot fresh weight (SFW), leaf area index, leaf dry weight, shoot dry weight, leaf N concentration, shoot N concentration, leaf N density, shoot N density and N nutrition index were measured at 54 and 72 days after transplanting. Grain yield, total number of spikelets, number of filled spikelets and 1000-grain weight were measured at harvest. 14,635 narrow-band NDVIs as combinations of reflectances at wavelength ${\lambda}l\;and\;{\lambda}2$ were correlated to the nine crop variables. One NDVI with the highest correlation coefficient with a given crop variable was selected as the NDVI of the best fit for this crop variable. As expected, models to predict crop variables before heading using the NDVI of the best fit had higher $r^2$ (>10\%)$ than those using common broad- band NDVI red or NDVI green. The models with the narrow-band NDVI of the best fit overcame broad- band NDVI saturation at high LAI values as frequently reported. Models using NDVIs of the best fit at booting showed higher predictive capacity for yield and yield component than models using crop variables.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.109-116
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• 1997

This experiment was carried out to examine the effect of various functional materials such as bioceramic podwers, crushed shells and elvanites supplemented to the each substrate on the seedlings growth of cucumber, watermelon and tomato. The seedlings were grown in pots filled with substrates of bioceramic podwers, crushed shell and elvanites. The growth of cucumber seedlings in terms of plant height, stem diameter, leaf width, leaf area, plant fresh and dry weight was promoted by adding the bioceramic. powder (1 to 2g/kg), crushed shells (20 to 80g/kg) or elvanites (20 to 80g/kg). Watermelon seedlings in terms of plant height, number of leaves and leaf area were greater than those of the control by adding bioceramics (1 to 2g/kg). Plant height was also promoted by the adding of bioceramic power from 16 days after treatment. But leaf area was increased from 8 days after treatment, while stem diameter was not affected. Watermelon seedlings were also influenced by adding curshed shells (20 to 80g/kg) and elvanites (20 to 40g/kg) into each substrate. The growth of characteristics of tomato seedlings were promoted by adding 1 to 3g/kg of bioceramics, 10 to 80g/kg of crushed shell or 20 to 40g/kg of elvanites, respectively. Especially, root growth was greatly influenced by bioceramic powder, whereas the shoot growth(leaves and stem) was stimulated by crushed shells and elvanites suppemented into substrate.

• Journal of Plant Biology
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• v.35 no.1
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• pp.17-23
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• 1992

Effects of polyamines and their biosynthetic inhibitors on adventitions shoot regeneration of Populus leaf segments were investigated. Polyamine inhibitors such as difluoromethyl arginine (DFMA), difluoromethyl ornithine (DFMO), and dicyclohexylamine (DCHA) decreased the fresh weight of cultured leaf segment and the rate of adventitious shoot regeneration. The inhibitory effects of DCHA were stronger than any other oplyamine inhibitors, and the rest were in the order of DFMO and DFMA. The inhibitory effects of these inhibitors were lessened or disappeared by the addition of polyamines, among which spermidine was the highest in its effect. Therefore, it is suggested that the spermidine may be related to the adventitious shoot regeneration of Populus leaf segments.gments.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.2
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• pp.196-200
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• 1993

A full understanding of the interdependence of leaf nitrate (($No_3$￣) metabolism and symbiotic nitrogen($N_2$) fixation in legume crops is needed to help maximize the use of both N sources as well as to improve forage quality through the inhibition of leaf nitrate accumulation. The present work examines the effects of added nitrate, the level of which are 0,2,4,8 and 12mM, on the nodule formation and leaf nitrate utilization and on the possibility of inducing nitrate-toxicity to livestocks in two alfalfa varieties, ' Vernal ' of grazing type and ' Victoria ' of hay type. Higher level of exogeneous nitrate resulted in the increased above-ground dry weight. Nodulation was inhibited severely when more than 8mM NO$_3$￣ was supplied to alfalfa plants, and leaf nitrate reductase reached a maximunm at 4mM nitrate supply. The $V_{max}$of nitrate reductase in leaves of Vernal was similar to that of Victoria, whereas the $K_m$ of Vernal was higher than that of Victoria. High accumulation of leaf nitrate, $4{\times}10^{-5}$ g/g leaf fresh weight, was shown at 12mM nitrate supply, which was thought to be not enough to induce nitrate-toxicity to livestocks.icity to livestocks.