This study evaluated the impact of sowing dates on the growth, yield, and nutritive quality of three corn cultivars including Gwangpyeongok, Dacheongok, and Shinhwangok. Plant height and total yield components declined with delayed sowing across all cultivars. Gwangpyeongok achieved the highest plant height (289 ± 14 cm), grain yield (9,108 ± 82 kg/ha), and total yield (18,973 ± 2,560 kg/ha) at the April 29 sowing. Dacheongok recorded the highest stover yield (17,227 ± 137 kg/ha) and total yield (22,236 ± 1,053 kg/ha) on May 13. Shinhwangok reached its maximum total yield (19,158 ± 604 kg/ha) at May 13 but showed the sharpest declines by May 16. Nutritional quality also deteriorated with later sowing. In stover, crude protein (CP) declined to 3.58% in Shinhwangok at May 16, accompanied by a rise in neutral detergent fiber (NDF) to 69.9%. In contrast, Dacheongok maintained stable CP levels (5.27–5.60%) and the lowest fiber fractions. Gwangpyeongok exhibited the highest stover CP at April 29 sowing, along with the lowest NDF and acid detergent fiber (ADF) contents. Grain CP was highest in Gwangpyeongok (8.1 ± 0.4%) and Shinhwangok (9.6 ± 0.9%) at April 29, while Dacheongok showed its maximum grain CP (8.0 ± 0.3%) at the same sowing date, coupled with relatively low fiber content. Overall, the findings highlight that timely sowing is crucial for achieving both high yield and optimal nutritive quality in maize. For Gwangpyeongok and Dacheongok, sowing from late April to mid-May provided the best balance between yield and nutritional quality. In Shinhwangok, the highest stover, grain, and total biomass yields were obtained at the May 13 sowing.

Waxy corn (Zea mays L.) is mainly consumed fresh, resulting in a significant amount of stover being left behind, including stalks, leaves, and tassels. Since approximately 1 kg of stover is produced for every 1 kg of corn grain, the potential to utilize stover as a valuable resource is substantial. This study aimed to evaluate the agronomic characteristics and feed value of major variety of waxy corn. Each waxy corn variety showed notable differences in traits like days to silking, plant height, and leaf characteristics, some varieties were found to be more suitable for silage production. Chalok 5 and Suwon 97, in particular, were found to be well-suited for silage due to their high dry matter yield and relative feed value, while Heukjinjuchal had a lower feed value, making it less suitable. Multivariate analysis showed that important feed value indicators, such as relative feed value and total digestible nutrients, were inversely related to neutral detergent fiber and acid detergent fiber. This relationship helped to clearly differentiate the characteristics of each waxy corn variety. Therefore, selecting waxy corn varieties with high dry matter yield and feed value, such as Chalok 5 and Suwon 97, can enhance farm income through both the sale of ears and the use of residual stover as a valuable resource, supporting sustainable agriculture.

초당옥수수는 고당도 옥수수 품종으로, 식단 트렌드 변화와 천연 당류에 대한 관심 증가로 인해 수요가 증가하면서 재배가 확대되고 있다. 초당옥수수는 높은 당도로 매우 달고 맛이 좋지만, 전분 함량이 낮아 일반 옥수수에 비해 발아율이 낮은 특징이 있다. 본 연구는 초당옥수수 계통의 전분 함량과 발아율의 상관관계를 조사하여, 우수한 생장과 발아율을 갖춘 고품질 계통을 선발하는 것을 목표로 하였다. 본 연구에서는 10개의 초당옥수수 계통을 대상으로 발아율과 식물체 생장 특성을 평가하였다. 모든 계통이 80% 이상의 발아율을 보였으며, KH51 계통이 53일로 가장 출사일이 빨랐고, KH29W 계통이 148cm로 간장이 가장 크게 나타났다. 고당도 계통을 선발하기 위해 수정 후 20일째에 이삭을 수확하여 유리당 함량을 측정하였다. KH28W 계통이 가장 높은 당 함량(23.3%)을 보였으며, KH45 계통이 가장 낮은 당 함량(8.1%)을 나타냈다. 또한, 전분 함량이 유리당과 비례하여 축적되는지를 확인하기 위해 수분 후 40일째에 이삭을 수확하여 분석한 결과, KH47 계통이 가장 높은 전분 함량(30.1%)을, KH28W 계통이 가장 낮은 전분 함량(23.6%)을 보였다. 전분 함량이 발아에 미치는 영향을 평가하기 위해 발아와 관련된 효소 및 유전자들을 분석하여, 발아 과정에서의 효소 활성 및 유전자 발현 수준을 측정하였다. 낮은 전분 함량은 발아 초기에 효소 활성과 유전자 발현을 저하시켜 발아 지연 및 불균일성을 초래하였으나, 발아 후 생장에는 큰 영향을 미치지 않았다. 이는 초당옥수수 종자의 초기 발아 과정이 유리당과 전분 함량에 의해 영향을 받을 수 있음을 시사한다.

Corn is essential for both humans and animals. The crop is the third most important food crop after rice and wheat. A rise in farming is resulting in a lack of self-sufficiency of high quality forages. Therefore, corn cultivars in Korea must be optimized to increase productivity and yield. A study was conducted in Pyeongchang, South Korea between 2021-2022 to evaluate the characteristics and productivity of three corn cultivars: Kwangpyeongok, AGR 41, and Nero IT. Different varieties of corn were sown in Pyeongchang on April 29 and April 27 of 2021 and 2022, respectively. The productivity and characteristics of the cultivars Kwangpyeongok, AGR 41, and Nero IT were evaluated during the yellowing ripening stage. The characteristics included the leaves, stems, grain, and stover content. Across different corn cultivars, there was no significant difference in stem height, diameter, forage or grain quantity based on an average of two years. Yet, significant differences were noted in the stem heights of all cultivars between 2021 and 2022 (p<0.05). There was a significant difference in the diameters of Kwangpyeongok and Nero IT between 2021 and 2022. A significant difference in forage yield was observed for Nero IT between 2021 and 2022. The yield of grains and forages was higher in 2021 than in 2022, which could be attributed to temperature and precipitation variations. We can conclude from these data that all cultivars in Pyeongchang showed significant productivity and yield, which could be useful to produce nutrient rich silage for livestock.

This study was conducted to find a way to improve quality by observing changes in quality and microbial communities according to whether corn silage was treated with additives and the storage period, and to utilize them as basic research results. The experimental design was performed by 2˟4 factor desigh, and the untreated (CON), and the additive inoculated (ADD) silage were stored and fermented for 30 (TH), 60 (ST), 90 (NT), and 120 (OHT) days, with each condition repeated 3 times. There was no change in the nutrient content of corn silage according to additive treatment and storage period (p>0.05). However, the change in DM and the increase in the relative proportions of lactic acid content and Lactobacillales according to the storage period (p<0.05) indicate that continuous fermentation progressed until OHT days of fermentation. Enterobacterales (33.0%), Flavobacteriales (14.4%), Sphingobacteriales (12.7%), Burkholderiales (9.28%) and Pseudomonadales (6.18%) dominated before fermentation of corn silage, but after fermentation, the diversity of microorganisms decreased sharply due to the dominance of Lactobacillales (69.4%) and Bacillales (11.5%), Eubacteriales (7.59%). Therefore, silage maintained good fermentation quality with or without microbial additives throughout all fermentation periods, but considering the persistence of fermentation even in long-term storage and the aerobic stability, it would be advantageous to use microbial additives.

Fall armyworm (FAW, Spodoptera frugiperda) is a major pest worldwide, and since its first domestic invasion was confirmed in 2019, its damage has been steadily increasing in crops such as corn until recently. In order to provide basic data for the management of FAW, we conducted a comparison of host preference and nutritional composition analysis of corn varieties. A total of 12 varieties of corn were selected for the experiment. To investigate the preference among the varieties, we examined the host preferences at the population level and the individual level, and found no statistically significant differences. In the population-level experiment, the highest damage rate was observed for Saekso 4 and the lowest for Heukgeom 2. In the individual-level experiment, the highest damage rate was found for Kangilok and the lowest for Oryun 2 when using leaves, and the highest for Saekso 1 and the lowest for Dreamok when using stems. As a result, the population-level and individual-level results were not consistent, suggesting that FAW's corn variety preference is not clear and may vary depending on various conditions such as corn tissue. Composition analysis of the 12 varieties showed no correlation between composition and FAW preference among the varieties, and considering the feeding behavior of FAW, which are highly polyphagous, it is recommended to control FAW as early as possible to improve control effectiveness.

전 세계적으로 RNA 간섭(RNA interference, RNAi)을 활용한 해충방제제 연구가 활발히 진행되고 있다. 대표적 으로 Monsanto의 서부 옥수수 뿌리벌레(Diabrotica virgifera virgifera) 특이적 방제용 dsRNA (DvSNF7)를 발현하 는 옥수수 종자가 상용화 되었고, 2016년 이 종자가 국내 사료 및 식품용으로 수입이 승인 되었다. 본 연구는 국내 에 서식하는 좁은가슴잎벌레(Phaedon brassicae)를 Non-target 곤충으로 사용하여, 옥수수 종자에 사용된 DvSNF7 dsRNA의 잠재적 위해성을 평가했다. P. brassicae의 SNF7 유전자와 DvSNF7 dsRNA 간 Sequence유사성 을 확인했다. 다음으로 P. brassicae가 DvSNF7 dsRNA를 섭식할 수 있는 환경을 조성하여, 치사 효과 실험과 Sequence특이적인 Knockdown효과를 확인하였다. 그 결과, DvSNF7 dsRNA는 P. brassicae생존에 영향을 미치지 않았으며, P. brassicae의 SNF7유전자를 Knockdown시키지 않음을 확인했다. 이번 연구를 통해 D. virgifera virgifera와 같은 과인 P. brassicae 는 SNF7유전자 간 Sequence유사성이 있지만, Sequence특이성이 부족하여 생존과 유전자 발현에 영향을 주지 않음으로써 위해성이 낮음을 확인했다.

Since rice is the main food in Korea, there are no regulations on corn milling yet. Corn is known as one of the world's top three food crops along with wheat and rice, and it is known that 3.5 billion people worldwide use corn for food. In addition, corn mills are not developed or sold in Korea, but the use of corn mills is increasing significantly in many countries in Southeast Asia. In the Philippines, as Korea's rice mill import increases, Korea's KAMICO (Korea Agricultural Machinery Industry Cooperative) and domestic company A agreed to develop a corn mill jointly with PHilMech, an organization affiliated with the Philippine Ministry of Agriculture. However, research on corn milling was very insignificant, so the development was carried out based on the technology of Korea's rice mill. Rice milling is performed by peeling off the skin of rice and producing brown or white rice, so it is carried out by removing the skin and cutting the skin. On the other hand, in the corn mill, the skin of the corn is peeled, pulverized and selected to produce main products suitable for edible use. Therefore, in order to develop a corn mill, processes such as peeling, transfer, grinding, sorting, and by-product separation are required, and suitable parts must be developed. In addition, the performance must be gradually improved through experiments in which corn is repeatedly milled. The Philippines produces 7.98 million tons/year of corn, which is about 100 times that of Korea, and is mostly consumed as a staple food. This is about 10% of the total crop production in the Philippines. In addition, the main cultivation complexes of corn are the mountainous regions of Tarlac or Pangasinan, and the produced corn is 72.4% of the so-called yellow corn called Arabel and Sarangani, and the remaining 27.6% are known as white corn. In this study, it was intended to produce grains of 2.5 mm or less suitable for food for yellow corn and to develop a corn mill for 200 kg per hour. Detailed conditions for development are stipulated as more than 55% of the main product recovery rate, more than 31% of the by-product recovery rate, less than 5% of the raw material loss rate, and more than 80% of the embryo dislocation rate. In this study, to achieve this, the overall process of the corn mill was developed, and the optimal conditions for the corn mill were obtained through the development of parts and empirical tests to improve performance. In addition, it was intended to achieve the development goal by evaluating and analyzing the performance of each part so that it did not conflict.

To produce super sweet corn sikhye, substituted for sweetener, the ratio of rice and super sweet corn was adjusted and processed with complex enzymes during saccharification, and their physicochemical and sensory properties were analyzed. The soluble solid content of the control and Corn-5 showed significantly high content at 13.50 °Brix, and the reducing sugar content of Corn-5 showed the highest content at 9.45%. The control showed the lowest free sugar content among all the experimental groups, excluding maltose content. In the enzyme-treated corn sikhye group, as the amount of super sweet corn increased, the content of sucrose decreased and the contents of glucose and fructose increased. The content of ascorbic acid and polyphenol compounds increased as the amount of super sweet corn increased. DPPH and ABTS radical scavenging abilities increased with increasing ratio of super sweet corn and enzyme treatment compared to the control. In the case of sensory evaluation, Corn-3, which substituted 30% of super sweet corn for rice and treated with enzymes, showed higher evaluations in taste, sweetness, and overall preference than those of the control.

To improve usability of super sweet corn, extracts were prepared with hydrolytic enzyme and changes in physicochemical and antioxidant properties were analyzed. Soluble solids and reducing sugars contents were higher in all enzyme treatment groups than in the control. When enzyme treatment time increased, contents of soluble solids and reducing sugars were also increased. There was no significant difference in lightness between treatment groups, with redness showing the highest value in the control and yellowness showing the highest value in the invertase treatment group. Free sugar content in the control was the lowest. However free sugar content in the enzyme combination treatment group was increased by more than four times compared to that in the control. Contents of ascorbic acid, flavonoids and polyphenols were higher in the enzyme treatment group than in the control. In particular, the enzyme combination treatment group showed the highest content. DPPH and ABTS radical scavenging abilities were significantly higher in all enzyme treatment groups than in the control. Radical scavenging abilities of cellulase treatment group and enzyme combination treatment group showed high activity. The activity increased when enzyme treatment time increased. The combined enzyme treatment method for super sweet corn was suitable for food processing.

Since maize (Zea mays L.) originated in central and south America, it requires warm climate conditions throughout its growing season. Growth halts when night-time temperatures drop below 10℃, and the plant may die if temperature reach -1.7℃. Thus, temperature should be maintained between 10 and 30℃ from seeding to maturity. The germination temperature for maize should be at least 8-11℃, whit an optimal range 32-34℃. Since temperature significantly affects the germination rate and period, it plays a crucial role in maize growth. In this study, we evaluated the quantity and feed value of 11 major varieties to determine those best suited for maize cultivation as feed in higher latitude, specifically in Democratic People’s of Republic of Korea, below 38 degrees north. A cultivation test was also conducted in Suwon in Republic of Korea, to assess adaptability in areas south of Mt. Suyang. Among the varieties tested, Shinhwangok2 reached silking the fastest, in 65 days, while Gwangpyeongok took the longest at 75 days. The stem length of all varieties exceeded 230 cm. Gwangpyeongok had the tallest stems, while Daanok and Shinhwangok2ho displayed the highest ear ratios. Dacheongok presented the highest values in both dry matter and TDN quantity, with 31,420 kg/ha and 21,66 kg/ha respectively. Pyeonggangok had the highest crude protein content at 8.0%. TDN (%) ranged from 57-68%, with Hwangdaok reaching up to 68%. Based on these findings, Dacheongok and Pyeonggangok appear to be the most suitable varieties for cultivation in terms of both quantity and feed value.