• Journal of The Korean Society of Grassland and Forage Science
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• v.33 no.2
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• pp.111-116
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• 2013

This experiment was carried out to select a resistant corn variety for rice black-streaked dwarf virus (RBSDV) disease in a RBSDV prevalent area (Gochang of Jeollabukdo) from 2006 to 2008. Ten corn varieties for silage preparation were cultivated with first cropping and second cropping system in an RBSDV field, and were tested outbreak rates of RBSDV and dry matter (DM) yield of forage. The outbreak rates of RBSDV were significantly different between corn varieties. Therefore, the resistance degree of corn varieties for RBSDV were divided into 4 groups; very resistant ('Kwangpeyongok' and 'Kwanganok'), resistant ('P3156' and 'P3394'), mildly resistant ('Cheonganok' and 'P32P75') and susceptible ('Suwon19', 'DK697' and 'GW6959') groups respectively. DM yield of forage in RBSDV fields exhibited comparatively significant differences between varieties (p<0.05). DM yield of resistant varieties ('Kwangpeyongok', 'Kwanganok', 'P3156' and 'P3394'), were higher (14~26%) than those of susceptible varieties ('Suwon 19', 'DK697' and 'GW6959'). Therefore, resistant varieties were recommended for increasing forage productivity in field of RBSDV prevalent areas.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.1
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• pp.39-44
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• 2001

Growth characters and productivities of corn varieties were compared to provide the basic data to the famers that in order to select the good corn varieties at Deakwanryoung district of Korea. Currently cultivated 8 recommended corn varieties and Suwon 19ho as check variety were used in this experiment and experimental design was randomized complete block with three replications. Resarch results obtained at Deakwanryoung branch (sea love 800m) of National Livestock Research Institute in 1999 are summarized as follows. Culm lengths of DK501 and GL4899 among corn varieties were shorter as 180cm and 198cm, respectively and rest of varieties were more or less 230cm and no difference among varieties. Inflorescence height was lower in varieties showing low culm length, and inflorescence heights of PK3525 and DK729 were higher about 10～15cm than those of other varieties. Stem diameters of all varieties except DK501 were thicker compared to check variety, Suwon 19ho and P3144W was thickest. Leaf numbers of late maturing DK729 and G4743 were higher as average 12 and 12.3 per plant, respectively. Silking dates among varieties were ranged from August 10 to 20 showing 10 day difference and DK501 was earliest as August 10 and G4743 was latest as August 20. Ear rates of early silking varieties were more than 46% and late silking varieties were less than 40%(P>0.1). Dry matter and TDN yield of P3351 was highest as 24,710 and 17,470kg/ha respectively, and DK729 and G4743 were second and third in order. In conclusion. early and medium maturing variety. P3352 with high yield and good growth characters was desirable at Deakwanryoung district of Korea.

• Korean Journal of Food Science and Technology
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• v.33 no.3
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• pp.313-318
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• 2001

Physicochemical properties of starch vermicelli (Dangmyun) made with different starches in laboratory were determined to develop a modified corn starch comparable to sweet potato starch which is highly expensive than corn starch but commonly used for starch vermicelli in Korea. Initial temperatures (Ti) of gelatinization of starch vermicelli made in laboratory measured by differential scanning calorimeter, which were above $60^{\circ}C$, were higher than those of starch vermicelli in the market. Their X-ray diffraction peaks were relatively sharp compared with those of starch vermicelli in the market, which showed that starches were not completely gelatinized during the process of starch vermicelli preparation in laboratory. Initial temperature (Ti) of corn starch vermicelli was decreased by $3^{\circ}C$ by hydroxypropylation but increased by $2.5^{\circ}C$ by oxidation. Hardness and compression slope of sweet potato starch vermicelli and mungbean starch vermicelli, which were $11,726{\sim}12,555\;g/cm^2$ and $29,914{\sim}30,604\;g/cm^2$, respectively, were the highest in the samples and those of waxy corn starch were lowest. Hardness and compression slope of starch vermicelli made with corn starch slightly oxidized in the concentration of 0.5% NaOCl at pH 9.0, $40^{\circ}C$ for 30 min. increased and found to be comparable to those of sweet potato starch vermicelli.

• Food Science and Preservation
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• v.20 no.4
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• pp.539-545
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• 2013

Effects of RS4 type resistant corn starch on the quality characteristics of cookies were investigated by physicochemical, instrumental and sensory evaluation. The resistant starch was made by cross-linking of corn starch as following; corn starch slurry was annealed at pH 2.0 and $50^{\circ}C$ for 2 h followed by the cross-linking reaction. The cross-linking reaction was performed at $50^{\circ}C$ for 12 h in the presence of 1.2%/st.ds NaOH, 10%/st.ds sodium sulfate and 10%/st.ds of sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture. Dietary fiber content of the resistant starch was estimated to be 73.8% by the AOAC method. For quality characteristics, dough pH decreased with the increase of the resistant starch content and spread factor decreased a little at 20% of the resistant starch. The moisture content and L value of cookies increased with the increase of the resistant starch content. However, the hardness and fracturability decreased with the increase of the resistant starch content. In the sensory evaluation, no significant differences were observed between the two cookies with or without the resistant starch. The results of this study suggest that the RS4 type resistant corn starch can be a good ingredient to increase dietary fiber content in cookies without changes of their qualities.

• Korean Journal of Human Ecology
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• v.3 no.1
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• pp.88-99
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• 2000

This study was perfomed to search for how properties of the starch viscosity appear in different qualities, when acetic acid is added. For this study, corn starch which belongs to A-type. Potato starch to B-type. and sweet potato starch to C-type were chosen as an experimental material. which was added to acetic acid controlled as pH 4.0, 4.5, and 5.0 at the time of before and after heating. After that, the viscosity properties of each starch was analyzed using Amylogram and Brookfield viscometer. As a result. the viscosity was shown high in an order of potato. sweet potato, and corn starch. According to addition of acetic acid. tile viscosity appeared to be low. The viscosity differences of before and after heating when the acid is added were shown as follows : Amylogram shows that the lower the pH is. the lower the viscosity is when the acid is added before-heating. In case the acid is added before-heating, gelatinization temperature, consistency and setback was increased. but breakdown decreased. In case the acid is added after-heating, the viscosity goes down at soon as it is added meanwhile consistency and setback was decreased. but breakdown increased. Such properties of the viscosity show a conspicuous variation in an order of potato. sweet Potato. and corn starch. Brookrield viscometer shows that the lower the apparent viscosity is. the lower pH is at the time of before-heating when the acid is added. In case of after-heating, when the acid is added. the apparent viscosity shows a higher inclination than that of before-heating in corn starch and sweet potato starch.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.142-146
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• 1989

Anther and/or tissue culture of cross pollinated crops would be very important because it can result in the direct use of haploids or doubled haploids for developing superior hybrids or varieties. The objective of the study was to investigate the response frequencies in anther and/or tissue-cultured hybrids of corn. pearl millet and buckwheat to identify agronomically acceptable germplasm of the crops. 27 crosses of corn inbred lines were evaluated by plating their anthers on N6. MS and Yu-Pei media. Two genotypes of FR1l41/FR16 hybrid cultured on N6 medium and Fla 2BT73/S6013 hybrid cultured on N6 medium responded with one anther producing calli when plated after 5$^{\circ}C$ low temperature treatment for one week. Immature embryos of corn hybrid Suwon 19 responded producing calli that were regenerated to plants at a 8.6 percent success rate. Of the 20 corn hybrids. immature tessels of FR1l41/FR16. B68/A1l6N//KS15. KS16/KS17. GA209/DB578 and SDB126/GA209 crosses responded at a relatively higher success rate producing calli that were regenerated to plants. In tissue culture of elongating culms of pearl millet x Napier grass interspecific hybrid. 2.5-4.0mm long pieces of the culm were good for callus induction resulting in higher success rate. The epicotyl of buckwheat was very good for tissue culture. and the node produced the plants regenerated directly without callus induction on the B5 medium containing I ppm BA and 0.05 ppm IBA. There were great differences in response to anther and/or tissue culture of corn, pearl millet and buckwheat due to genotype x medium and environment interactions.

• Korean Journal of Poultry Science
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• v.10 no.1
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• pp.46-52
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• 1983

The study was carried out to examine factors affecting metabolic plus endogenous one.9y (FEm＋UEe) losses by adult roosters. Experiment one was performed to examine the effect of excreta collecting period and Experiment two, of feeding soluble carbohydrates (corn starch and glucose) to birds on FEm＋UEe losses. The results obtained were as follows : 1. The excreta voided, energy and energy losses by the roosters during collecting period II (24-48hr) were generally higher than those of period I, at though there was no significant difference (P＞.05). 2. There was not found correlationship between body weight (X) and excreta voided, energy and nitrogen losses IY) (P＞.05). The fact supported that body weight of birds did noy affect the losses of FEm＋UEe by adult rooster. 3. The feeding of glucose and mixture (corn starch＋glucose) decresed excreta voided, energy and nitrogen losses significantly (P＜.05) comparing with those of unfed birds. 4. The excreta voided, and nitrogen loss of birdsfed corn starch were much lower thu those of unfed birds. Fact that FEm＋UEe losses was not significantly different (P＞.05) between birds fed corn starch and unfed birds was indicative that apparent digestibility of corn starch was much lower than that of glucose ana mixture. 5. Nitrogen loss of fed birds was greatly reduced comparing with that of fed birds. The finding was indicative that the carbohydrates input was ultilized to supplemented energy loss through the catabolism of body tissue during fasting.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.2
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• pp.85-91
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• 2000

Antioxidant activity and related components including tocopherols, phenolic compounds and carotenoids in the corn(Zea mays L.) kernels were measured to understand effects of fertilizer application. Hybrids used were Chalok 2, a waxy corn, and Suwon 19, a dent corn. The standard fertilizer level of N-P-K was 14.5-3-6 for Chalok 2 and 17.4-3-6.9 for Suwon 19. The treatments of the fertilizer levels were the standard level, half and two fold amounts of N, P, and K, and no fertilizer. The antioxidant activity was determined by measuring electron donating ability. The antioxidant activity of Chalok 2 was higher than Suwon 19. The antioxidant activity was the highest at the standard fertilizer treatment for Chalok 2, but was statistically not significant. The antioxidant activity and the related compounds content in Suwon 19, however, were the highest in the two fold nitrogen treatment, and the differences were significant. The contents of tocopherols, phenolic compounds and carotenoids were 30.0~38.1, 104.7~118.8, $0.1{\mu}gml^{-1}$, respectively for Chalok 2 and 16.7~20.1, 59.9~72.7, $35.5{\sim}50.0{\mu}gml^{-1}$, respectively for Suwon 19. The antioxidant activity was positively correlated with the grain yield in both cultivars. The shorter the ASI the higher the yield of the plant. The difference in genetic factors would affect greater influence than fertilizer effect on the antioxidant activity of corn.

• Korean Journal of Organic Agriculture
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• v.25 no.1
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• pp.171-185
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• 2017

${\gamma}$-aminobutyric acid (GABA) is a non-proteinogenic amino acid biosynthesized through decarboxylation of L-glutamic acid by glutamic acid decarboxylase. GABA is believed to play a role in defense against stress in plants. In humans, it is known as one of the major inhibitory neurotransmitters in the central nervous system, exerting anti-hypertensive and anti-diabetic effects. In this report, we wanted to enhance the GABA production from the barley leaf and corn silk by culturing them with lactic acid bacteria (LAB). The barley leaf and corn silk were mixed with various weight combinations and were fermented with Lactobacillus plantarum in an incubator at $30^{\circ}C$ for 48 h. After extracting the fermented mixture with hot water, we evaluated the GABA production by thin layer chromatography and GABase assay. We found that the fermented mixture of the barley leaf and corn silk in a nine to one ratio contained a higher level of GABA than other ratios, meaning that the intermixture and fermentation technique was effective in increasing the GABA content. We also tested several biological activities of the fermented extracts and found that the extracts of the fermented mixture showed improved antioxidant activities than the non-fermented extracts and no indication of cytotoxicity. These results suggest that our approach on combining the barley leaf and corn silk and its fermentation with LAB could lead to the possibility of the development of functional foods with high levels of GABA content and improved biological activities.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.1
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• pp.1-8
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• 1998

To compare different methods for the determination of available soil P in the relationship between the soil P and plant uptake of P, rice and corn were cultivated in the pot filled with soils of different available P contents. The soils were taken from 20 rice fields and 20 upland soils. The available soil P were determined before the experiment by Olsen, Lancaster, Bray 1, Bray 2, Mehlich II and Calcium lactate methods and the correlations between the available soil P measured by different methods and the amount of P taken up by corn at 10 leaf stage and by rice at maximum tillering stage were investigated. In upland soils, the available P measured by all the methods was linearly regressed with high significance to the amount of P taken up by corn. The coefficients of determination($R^2$) in the regression equations ranged from 0.596(Calcium lactate method) to 0.891(Olsen method). In rice soils, the soil available P did not regressed by first-order to the amount of P taken up by rice plant, while Michaelis-Menten equation better explained the relationship between the two parameters. In the Michaelis-Menten equation the coefficients of determination for each analytical method ranged from 0.607(Mehlich II method) to 0.923(Lancaster method). Based upon these observations it is concluded that for testing of available P for corn soils Olsen, Bray 2 and Lancaster methods are equally superior to other methods. For rice soils Lancaster, Bray 1, and Bray 2 methods are better than others.