• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.477-484
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• 2020

This study was conducted to investigate the effects of slow-releasing fertilizer and sowing date on waxy corn propagated through double cropping without tillage. "Mibaek 2" was sown for first cropping on March 25^th, April 5^th, and April 15^th, and for second cropping on July 5^th, July 15^th, and July 25^th in 2018-2019. In order to save labor, slow-releasing fertilizer was utilized only one time before sowing. The accumulated temperature from sowing to silking was about 590-700℃. It took 65-77 days when "Mibaek 2" was sown in early April, but the one sown in early July took 42-52 days. In the first cropping, the culm length and ear length caused by the sowing date had no statistical significance, but the kernel set length was the highest at 123 cm in the sowing district on April 5^th. The weight of marketable ears was the highest at 100%, in addition to soil testing-based recommended fertilization. Meanwhile, in the second cropping, culm length, ear length, and yield were less compared to the first cropping. The culm length, kernel set length, ear length, and seed set length decreased as sowing date was delayed. The number and yield of marketable ears were the highest at 100%, in addition to soil testing-based recommended fertilization like in the first cropping. It has been found that securing yield by July 15^th to finish the second seeding of the crop in the central part of Korea is advantageous. These results of this study will be helpful to farmers for the double cropping of waxy corn cultivation and management.

• Food Science and Preservation
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• v.8 no.3
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• pp.246-251
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• 2001

This study was conducted to investigate the change of qualities of peaches by different packing types and humidity during storage period. The weight loss ratios of 'Kulakatawase' and 'Mibaek' by non-packing were about 6.8% and 4.9% for 4 days storage at room temperature, respectively whereas, the peaches by packing with 30㎛ LDPE were less than 1% for 25 days storage at low temperature and high humidity(95 $\pm$3%). The firmness values of the peaches were not decreased during storage at low temperature compared to the firmness values of the peaches during storage at room temperature. Little difference of total acidity and soluble solids of the peaches was during storage at low temperature. The contents of fructose and glucose in peaches were increased slightly after storage for 25 days but that of sucrose was decreased slightly. When peaches were stored at low temperature(0∼2$\^{C}$) and high humidity(95$\pm$ 3%) after packing with 30㎛ LDPE or 25㎛ perforated polyolefin film 'Kurakatawase ' and 'Mibaek' were able to storage for 20 and 25days, respectively.

• Korean Journal of Remote Sensing
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• v.37 no.4
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• pp.733-745
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• 2021

Although waxy corn varieties developed after the 1980s show differences depending on development stages and conditions, studies on the characteristics of waxy corn during the growth stage are rare. The subject of this study was a field survey and unmanned aerial vehicle (UAV) image acquisition of four waxy corn varieties cultivated in Idam-ri, Gammul-myeon, Goesan-gun, Korea. The study was conducted in four stages at intervals of two weeks after planting in 2019. The growth characteristics of each of the four varieties were analyzed using growth curves obtained based on field survey and UAV imagery data. The characteristics of each growth stage of the four varieties of corn, as assessed using normalized difference vegetation index (NDVI) and plant height (P.H.) values, were as follows. The growth model was identified as a model in which three-parameter logistic (3PL) curves reflect the growth characteristics of corn well. In particular, it was found that the variations in growth rate shown by P.H. and NDVI values clearly explain the differences between corn varieties. Among the four cultivars, growth and development first occurred at the early vegetative stage in Daehakchal, followed by Mibaek 2, Miheukchal, and finally Hwanggeummatchal. The variationsin P.H. and NDVI were achieved quickly and earlier in Daehakchal, followed by Mibaek 2, Hwanggeummatchal, and Miheukchal. It was confirmed that these results reflected the characteristics of the fast white-type varieties, while the black-type varieties were delayed, as in a previous study. These results reflect the resistance to lodging that affects the cultivation environment and the response characteristics to nutrients and moisture. It was confirmed that UAV accurately provides growth information that is very useful for analyzing the growth characteristics of each corn variety.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.329-336
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• 2016

Occurrence of oriental corn borer, Ostrinia furnacalis, and yield in a paddy-upland rotation field for 8 maize (Eolrukchal 1, Heugjeom 2, Miheukchal, Ilmichal, Heukjinjuchal, Chalok 4, Mibaek 2, Daehakchal) and 7 sorghum (Hwanggeumchal, Anzunbaengisusu, Moktaksusu, Sodamchal, DS-202, Nampungchal, Donganme) varieties has been surveyed. In a monitoring study using a pheromone trap carried out from 15 May to 10 September, the density of O. furnacalis adults increased rapidly from about 2 weeks after maize planting and reached the highest density at mid June. After that, their density was fluctuated a little at earlier September. The number of the damaged maize and invasive pores on the stem of 2 maizes and sorghum varieties was examined. The mean number of the damaged maize per 20 plants was 19 and 18 plants, and the number of invasive pores was 1.8 and 1.4 per maize stem in Daehakchal and Mibaek 2, respectively. In a survey carried out at harvest period using 8 maize varieties, the damaged ratio was 94%, 92%, 71%, 64%, 54%, 52%, and 45% in Daehakchal, Mibaek 2, Ilmichal, Eolrukchal 1, Chalok 4, Miheukchal, and Heugjeom 2, respectively. The number of invasive pore per Ilmichal stem was 1.4 and that of the others was less than 1.0 per stem. In addition, the damaged ratio of maize ears was 50% in Ilmichal, 40% in Heukjinjuchal, 37% in Daehakchal, etc. The damage pattern of 2 sorghum varieties, Nampungchal and Donganme, by O. furnacalis larvae was steeply increased from planting to 2 months and the trend was continued up to earlier August. At this time, the mean number of damaged sorghum was 13 and 9.2 plants for Nampungchal and Donganme, and the number of invasive stem pores was 1.06 and 0.46, respectively. In another survey carried out at harvest period for 7 sorghum varieties, their damaged ratio was 95% in DS-202, 76% in Moktaksusu, 75% in Sodamchal, 67% in Nampungchal, 57% in Anzunbaengisusu, 46% in Donganme, and 34% in Hwanggeumchal. The damage of sorghum varieties was much higher and severer than that of maizes by O. furnacalis larvae. The number of invasive pores on a sorghum stem was 1.7 in DS-202, 1.4 in Moktaksusu, 1.3 in Sodamchal, 1.1 in Nampungchal, 1.0 in Anzunbaengisusu, 0.5 in Donganme, and 0.4 in Hwanggeumchal. Meanwhile, there was no distinct connection between damaging results and yields of maizes and sorghums by O. furnacalis larvae in a paddy-upland rotation field. These results from this study can be applicable for the establishment of a management strategy to control Oriental corn borer in paddy-upland rotation fields for maize and sorghum.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.269-277
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• 2019

It is important to determine sowing date as it decisively affects the quality as well as quantity of waxy corn. In the central northern area of Korea, optimum sowing date of waxy corn is May and requires about 20-26 reproductive growth days from silking date to harvest. We determined adaptable sowing date of waxy corn varieties using growing degree days (GDDs), especially in the central northern area. Earlier sowing required many more emergence days owing to the low temperature. All waxy corn varieties required about 16~22 emergence days when sown in April. Otherwise, less than 15 emergence days were needed for sowing from May to August. Sowing dates to maximize ear yield of waxy corns were different depending on the eco-types of corn varieties as well as GDDs during the growth period. Early maturity type Mibaek2' showed the highest ear yield at the May $15^{th}$ sowing date. Middle maturity 'Iimichal' and late maturity 'Chalok4' showed the highest ear yield at the May $25^{th}$ and June $5^{th}$ sowing dates, respectively. GDDs of 26 days after silking was an index to determine the highest yield sowing date of 'Mibaek2'. The total GDDs from sowing to harvest and to silking were other indexes to determine the highest yield sowing date of 'Ilmichal' and 'Chalok4', respectively. Generally, it required about $2,400^{\circ}C$ GDDs from sowing date to maturity and at least 65 days of silking date from sowing to obtain about 1,200kg of ear yield of waxy corn in the central northern area of the Korean peninsula. The results of the study will be helpful for corn farmhouses to determine optimum sowing date of waxy corn in the central northern area of Korea.

• Korean Journal of Organic Agriculture
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• v.26 no.3
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• pp.409-425
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• 2018

Occurrence and yield characteristics of lepidopteran insect pests in both PUR (paddy-upland rotation) and CU (continuing upland) fields for 8 maize (Eolrukchal 1, Heugjeom 2, Miheukchal, Ilmichal, Heukjinjuchal, Chalok 4, Mibaek 2, Daehakchal) and 7 sorghum (Hwanggeumchal, Anzunbaengisusu, Moktaksusu, Sodamchal, DS-202, Nampungchal, Donganme) varieties was surveyed. The population of Ostrinia furnacalis adults showed 3 times highest peaks in 2016. In addition, the damaged ratios of maize and sorghum leaves and stems were increased depending on the growth periods of the crops and those by O. furnacalis larvae were also increased steeply in mid August. The damaged ratios of maizes such as Miheukchal, Eolrukchal 1, Ilmichal, Heugjeom 2, and Mibaek 2 by O. furnacalis larvae were statistically different (P=0.05) between organically managed PUR and CU fields. Except for DS202 among sorghum varieties, the damaged ratios of the other ones were high and similar (50-92%) in the CU field. The ear damaged ratio of maize varieties by lepidopteran larvae including O. furnacalis and Helicoverpa armigera was from 5 to 38% in Chalok 4 and Heukjinjuchal, respectively, and Daehakchal gave relatively higher damage ratio in the PUR field (33%) than in the CU field (14%). The ear ratio of Sodamchal and DS-202 varieties in the PUR field was 94 and 82%, and all sorghum varieties were damaged over 78% by lepidopteran larvae in the CU field. Interestingly, the correlation coefficients between the damaged ratio and invasive pores on their stems by O. furnacalis larvae were positive (maize $r=0.69_{paddy-upland}$, $0.95_{continuing}$; sorghum $r=0.93_{paddy-upland}$, $0.97_{continuing}$, respectively). Additionally, the correlation coefficients between the damaged ratio and the ear weight or the thousand kernel weight (g) of maizes and sorghums by lepidopteran larvae were negative (maize $r=-0.38_{paddy-upland}$, $-0.49_{continuing}$; sorghum $r=-0.70_{paddy-upland}$, $-0.57_{continuing}$, respectively). These results indicate that the focused management on lepidopteran insect pests occurring maizes and sorghums cultivated in PUR and CU fields is an important strategy to secure their yields.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.6
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• pp.843-852
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• 2010

Hydroxycinnamic acid derivatives (HADs) and anthocyanins in corn (Zea mays L.) have recently been reported to have anticarcinogenic, anti-hypertensive, antidiabetic, antifungal, antioxidant, and anti-melanogenic activities. Five HADs and anthocyanins in corn were quantified by HPLC according to cultivars and heat processes. In addition, major anthocyanin of a black waxy corn was isolated and identified by several instrumental analysis, and its content was also quantified by HPLC according to heat processes. Of the ten corn cultivars, five waxy corn cultivars had moderate five HADs contents except "Baksa" waxy corn with higher two free cinnamic acids (FCAs), p-coumaric and ferulic acids. In contrast, three dent corn cultivars contained higher levels of three polyamine conjugates (PCs), CFP, DCP and DFP, and especially "P3394" had the highest amount of the three PCs. Two sweet corn cultivars had generally intermediate HADs levels between waxy and dent corn cultivars. Of the three colored-waxy corns, a black Mibaek waxy corn had the highest anthocyanin content. During heat processes, levels of two FCAs in the black waxy corn generally increased, whereas no significant change on three PCs contents was observed except the puffing process. Roasting, retort and puffing processes significantly increased two FCAs and especially, the puffed black waxy corn had the highest amount of FCAs. Meanwhile, most heat treatments except retort process, considerably decreased total anthocyanin contents, and especially the puffed black waxy corn had nearly no anthocyanin. Level of one major anthocyanin, pelargonidin 3-glucoside (P3G) isolated from a black waxy corn was appreciably decreased by heat treatments except retort process, which greatly increased P3G content. These results suggest that the retorted black waxy corn may be a promising high quality functional corn product.