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.

This study was conducted with the aim of confirming the impact and relative contribution of extreme weather to dry matter yield (DMY) of silage corn in the central inland region of Korea. The corn data (n=1,812) were obtained from various reports on the new variety of adaptability experiments conducted by the Rural Development Administration from 1978 to 2017. As for the weather variables, mean aerial temperature, accumulated precipitation, maximum wind speed, and sunshine duration, were collected from the Korean Meteorological Administration. The extreme weather was detected by the box plot, the DMY comparison was carried out by the t-test with a 5% significance level, and the relative contribution was estimated by R2 change in multiple regression modeling. The DMY of silage corn was reduced predominantly during the monsoon in summer and autumn, with DMY damage measuring 1,500-2,500 kg/ha and 1,800 kg/ha, respectively. Moreover, the relative contribution of the damage during the monsoons in summer and autumn was 40% and 60%, respectively. Therefore, the impact of autumn monsoon season should be taken into consideration when harvesting silage corn after late August. This study evaluated the effect of extreme weather on the yield damage of silage corn in Korea and estimated the relative contribution of this damage for the first time.

This study aimed to investigate the impacts of extreme weather on the dry matter yield (DMY) of silage maize in South Korea. The maize data (n=3,041) were collected from various reports of the new variety of adaptability experiments by the Rural Development Administration (1978-2017). Eight weather variables were collected: mean temperature, low temperature, high temperature, maximum precipitation, accumulated precipitation, maximum wind speed, mean wind speed, and sunshine duration. These variables were calculated based on ten days within seeding to harvesting period. The box plot detected an outlier to distinguish extreme weather from normal weather. The difference in DMY between extreme and normal weather was determined using a t-test with a 5% significance level. As a result, outliers of high-extreme precipitation were observed in July and August. Low-extreme mean temperature was remarkable in middle May, middle June, and late July. Moreover, the difference in DMY between extreme and normal weather was greatest (5,597.76 kg/ha) during the maximum precipitation in early July. This indicates that the impact of heavy rainfall during the Korean monsoon season was fatal to the DMY of silage maize. However, in this study, the frequency of extreme weather was too low and should not be generalize. Thus, in the future, we plan to compare DMY with statistical simulations based on extreme distributions.

The purpose of this study was to investigate the Maillard reaction–related physicochemical properties of three maize varieties (Kwangpyeongok, Sinhwangok2ho and Gangdaok) after roasting them for different times (0, 15, 25, 40, and 55 minutes). The Maillard reaction is a non-enzymatic browning reaction involving reducing sugars and amino compounds. The content of reducing sugar, the causative agent of the Maillard reaction, decreased as roasting time increased. Gangdaok showed the lowest reducing sugar content of 1.04 mg/g after 55 minutes of roasting. In the elapsed roasting time, chromaticity ‘L’ and ‘b’ values decreased. At 55 minutes of roasting, wherein the Maillard reaction occurred most actively, Gangdaok showed the lowest ‘L’ value of 56.37 and the highest ‘a’ value of 7.60. Gangdaok had superior conditions for inducing the Maillard reaction compared to other varieties, and it is consider that 'flint–type', an endosperm characteristic, may have been the influencing agent. This study detected a total of 52 types of volatile aroma compounds (VACs), of which 28 were produced after roasting. Of the total VACs detected, 2-Formyl-5-methylfuran and 2-Furancarboxaldehyde accounted for 43.8~45.5% and have been confirmed to be the major VACs present in roasted maize. Most of the correlations between the Maillard reaction–related characteristics showed high correlation coefficients.

This study was carried out to investigate the effects of planting densities on the growth characteristics, dry matter yield, and feed value of “Geukdong 6” (a new variety of corn for feed). The experimental design was arranged in a randomized block design with three replications. Treatments consisted of six planting densities, 60 cm × 25 cm (T1), 60 cm × 30 cm (T2), 70 cm × 25 cm (T3), 70 cm × 30 cm (T4), 80 cm × 25 cm (T5) and 80 cm × 30 cm (T6). All treatments were sown on May 14, 2021, and the harvest was on October 3 (late flowering). Plant length and the number of tillers were the highest in T5 (p<0.05), but the number of leaves and stem diameter were the highest in T6 than in the other treatments (p<0.05). Leaf length, leaf width, and dead leaf were not significantly different among the treatments. Organic matter was highest in T6, and crude protein was highest in T5 (p<0.05). The ether extract was not significantly different among the treatments. Crude fiber, NDF, and ADF were highest in T2 with relatively higher planting density (p<0.05). Calcium and phosphorus were not significantly different among the treatments. TDN content was the highest in T3 (p<0.05). Sugar degree (Brix), fructose, glucose, dextran, isomerose, and inverted sugar were not significantly different among the treatment. Fresh yield, dry matter yield and TDN yield were higher in order of T6 > T5 > T4 > T3 > T2 > T1 (p<0.05). Relatively feed value was higher in order of T3 > T6 > T5 > T1 > T4 > T2 (p<0.05). Based on the above results, planting density could be recommended from 80 cm × 30 cm for efficient production of “Geukdong 6”.

The objective of this study was to verify the effect of pig slurry application with acidification and biochar on feed value, nitrogen use efficiency (NUE) of maize forage, and ammonia (NH3) emission. The four treatments were applied: 1) non-pig slurry (only water as a control, C), 2) only pig slurry application (P), 3) acidified pig slurry application (AP), 4) acidified pig slurry application with biochar (APB). The pig slurry and biochar were applied at a rate of 150 kg N ha-1 and 300 kg ha-1, respectively. The AP and APB treatments enhanced all feed values compared to C and P treatments. The NUE for plant N was significantly increased 92.1% by AP and APB treatment, respectively, compared to the P treatment. On the other hand, feed values were not significantly different between AP and APB treatments. The acidification treatment with/without biochar significantly mitigated NH3 emission compared to the P treatment. The cumulative NH3 emission throughout the period of measurement decreased by 71.4% and 74.8% in the AP and APB treatments. Also, APB treatment reduced ammonia emission by 11.9% compared to AP treatment. The present study clearly showed that acidification and biochar can reduce ammonia emission from pig slurry application, and pig slurry application with acidification and biochar exhibited potential effects in feed value, NUE, and reducing N losses from pig slurry application through reduction of NH3 emission.

The objective of this study was to prove the effect of pig slurry application with charcoal on nitrogen use efficiency (NUE), feed value and ammonia (NH3) emission from maize forage. The four treatments were applied: 1) non-pig slurry (only water as a control), 2) only pig slurry application (PS), 3) pig slurry application with large particle charcoal (LC), 4) pig slurry application with small particle charcoal (SC). The pig slurry was applied at a rate of 150 kg N ha-1, and the charcoal was applied at a rate of 300 kg ha-1 regardless of the size. To determine the feed value of maize, crude protein, dry matter intake, digestible dry matter, total digestible nutrient, and relative feed value were investigated. All feed value was increased by charcoal treatment compared to water and PS treatment. Also, the NUE for plant N was significantly higher in charcoal treatments (LC and SC) compared to PS treatment. On the other hand, there is no significant difference for feed value and NUE between LC and SC. The NH3 emission was significantly reduced 15.2% and 27.9% by LC and SC, respectively, compared to PS. Especially, SC significantly decreased NH3 emission by 15% compared to LC. The present study clearly showed that charcoal application exhibited positive potential in nitrogen use efficiency, feed value and reducing N losses through NH3 emission.

본 연구는 남부지역에서 사료용 옥수수(Zea mays L.)의 수량과 기후요인 간의 상관관계를 비교하기 위하여 수행하였다. 실험에 사용한 사료용 옥수수 품종은 광평옥이었으며, 2017년에서 2019년까지 3년간 경상남도(진주)와 전라남도(나주, 장흥)의 시험포장에서 각각 수행하였다. 사료용 옥수수의 평균 간장은 경상남도에서 250.1±52.9 cm로 전라남도의 215.2±25.2 cm 보다 유의적으로 더 높게 나타났다. 암이삭 평균 착수고의 경우에도 경상남도가 119.8±31.4 cm로 전라남도의 89.5±18.3 cm 보다 더 높게 나타났다. 옥수수의 평균 총 건물수량은 유의적 차이는 없었으나, 경상남도에서 16045±5012 kg·ha-1로 더 많았다. 이러한 차이는 옥수수 유식물 정착기인 5월 중의 유효적산온도와 강수량, 그리고 전 생육기간 중의 일조시간 등이 경상남도 지역이 더 많았기 때문으로 판단된다. 암이삭의 평균 건물수량은 경상남도가 6363±2728 kg·ha-1로 전라남도의 3998±2750 kg·ha-1 보다 더 많았는데, 이는 개화결실기 때의 평균 최고기온에 노출정도의 차이에 의한 것으로 추측된다. 사료용 옥수수의 기후요인과 건물수량과의 상관관계를 분석한 결과, 5월 강수량(0.54)과 6월 강수량(0.52), 그리고 8월 평균기온(0.60)과 8월 평균 최고기온(0.60)이 가장 높은 양의 상관관계를 나타내었으며, 경엽부 건물수량도 유사한 경향을 나타내었는데, 이는 초기 유식물 생육기의 강수량이 건물수량에 미치는 영향이 중요하며, 여름철 고온기인 8월의 기온이 C4작물인 옥수수의 생장에 중요한 요인으로 영향을 미친 것으로 판단된다. 또한 암이삭 건물수량은 웅수와 암이삭이 직접 대기에 노출되는 시기인 7월의 평균기온(-0.85)과 평균 최고기온(-0.79)과 음의 상관관계를 나타내어, 개화 수정기 때의 고온이 결실률에 영향을 미치는 중요한 요인임을 추측할 수 있었다. 향후 기후요소가 옥수수의 생육 및 생산성에 미치는 영향을 더욱 정확하게 분석하기 위한 데이터 축적을 위해서는 추가적인 후속 연구가 수행되어야 할 것으로 판단된다.

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 24th and the silking date was July 27th, but the P2105 variety was late to July 28th and August 1st, 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.

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.

본 연구는 남부지역논토양에서의 풋찰옥수수를 활용한 2모작 작부체계 확립을 위해 풋찰옥수수의 파종시기별 경운 및 이랑너비에 따른 일미찰 옥수수의 생육특성 및 토양의 수분특성을 알아본 결과는 다음과 같다. 파종시기에 따른 초장은 3월 30일 처리구에서 길게 나타났으나, 경직경과 엽수는 4월13일 처리구에서 굵거나 많았다. 초 장에서는 두 파종시기 모두 쟁기·로터리+60 cm 처리구에서 176, 154 cm로 가장 길게 나타났으며, 로터리+120 cm 처리구에서는 가장 짧은 144, 118 cm로 조사되었다. 경직경에서도 쟁기·로터리+60 cm 처리구에서 가장 굵게 나타났다. 재배기간동안 토양수분함량 변화는 쟁기·로터리+60 cm 처리구에서 변화 폭이 가장 큰 것으로 나타났다. 이삭중, 이삭장, 이삭직경 및 이삭열수는 쟁기·로터리+60 cm 처리구에서 가장 높은 값으로 조사었으나, 로터리+120 cm 처리구에서 가장 낮은 값이 나타났다. 풋이삭수량에서는 파종시기에서는 3월 30일 처리구에서 평균 80 kg 10a-1 더 높았으며, 파종시기별 쟁기·로터리 +60 cm 처리구에서는 가장 높았으나, 로터리+120 cm 처리구에서는 12.2~12.7% 감소한 것으로 나타났다. 따라서 남부지역 논토양에서 풋찰옥수수를 활용한 2모작 작부체계에서는 3월 말경 쟁기처리한 후, 이랑너비를 좁은 1열 고휴재배법으로 재배하는 것이 유리한 것으로 사료된다.

This study was carried out to investigate the effects of seeding dates and cultivated period on the growth characteristics, dry matter yield and feed value of Teosinte new variety “Geukdong 6”〔Zea mays L. subsp. mexicana (Schrad.) H. H. Iltis〕for feed. The experimental design was arranged in a randomized block design with three replications. Treatments consisted of five time seeding dates, 10 May(T1), 25 May(T2), 10 June(T3), 25 June(T4) and 10 July(T5), and same time harvesting, 22 October. Therefore, growing period were 164 days(T1), 149 days(T2), 134 days(T3), 119 days(T4) and 103 days(T5), respectively. In growth stage at harvest time, T1, T2, T3, T4 and T5 were early flowering, end heading, middle heading, early heading and early heading stage, respectively. Plant length and dead leaf were highest in T1, but leaf width and number of leaf were highest in T2 than others (p<0.05). Leaf length, stem diameter and number of tiller were not significantly different among the treatments (p<0.05). Stem hardness was higher in order of T1(2.0)> T2(1.9) > T3=T4(1.7) > T5(1.2kg/cm2). Fresh yield and dry matter yield showed significantly higher as the sowing time was faster and the cultivation period was longer (T1 > T2 > T3 > T4 > T5, p<0.05). Crude protein, crude fat and TDN content were highest in T5, but ADF and NDF content were highest in T1 than others (p<0.05). T1, T2 and T3 showed significantly higher crude protein yield compared to T4 and T5 (p<0.05). Total digestible nutrients yield were higher in order of T1 > T2 > T3 > T4 > T5 (p<0.05), and relative feed value were higher in order of T5 > T4 > T3 > T2 > T1 (p<0.05). Based on the above results, seeding dates could be recommended from the early May to the late May, and it is efficient that the cultivation period is over 150 days for dry matter yield, crude protein yield and total digestible nutrients yield.

We used the upland field rotated from matured rice paddy field, which have been used as a rice paddy field long time, for three years from 2015 to 2017. Therefore, this study was conducted for three main purposes. The first was to investigate yearly changes of growth and yield for waxy maize in the organic farming waxy maize at rice paddy-upland rotation system, the second was to investigate yearly changes of soil physical and chemical characteristics of rice paddy field soil in organic farming waxy maize at rice paddy-upland rotation system and the third was to select the suitable varieties for organic farming waxy maize at rice paddy-upland rotation. The test varieties were that 8 varieties of waxy maize of Mibaek 2, Ilmichal, Daehakchal, Chalok 4, Miheukchal, Eolrukchal 1, Heukjinjuchal, Heugjeom 2. For yearly yield, the highest yield was obtained in the first year of 949.6 kg, the second highest was in the third year of 680.6 kg 10a-1, while the second year was the lowest yield (675.4 kg 10a-1). Both varieties of Chalok 4 and Ilmichal showed the highest yield with about 900 kg 10a-1 in the threeyear average of 8 varieties. Solid phase of deep soil was 10% higher than that of top soil. Porosity rate of the top soil (54.7%) was higher than that of deep soil (49.4%), and the porosity in the third year was 2.7% higher than that of the first year. Soil organic matter content was significant different between soil depths and between three years. Soil solid and liquid phase decreased by 1.6% and 4.3%, respectively, compared to the first year, and the gas phase increased by 4.3%. The porosity of the third year was 2.7% higher than that of the first year. The soil organic matter content was 9.5 g kg-1 in the third year compared with 12 g kg-1 in the first year. It has also trend to decrease as the number of years rotated from rice paddy field increased. In the three-year average yields of Ilmichal and Chalok 4 were 898.1 kg 10a-1 and 891.6 kg 10a-1 respectively and the yield of Chalok 4 was greater than the other 7 varieties. We compared and selected the two best waxy maize varieties of Chalok 4 and Ilmichal for rice paddy-upland rotation. When we look at the yearly variation for waxy maize, Waxy maize yield was the highest in the first year and decreased year by year. Therefore, it would be better to restore upland field to rice paddy fields after the first year.

Waterlogging strongly affects maize (Zea mays L.) growth. It is necessary to find the screening method of waterlogging tolerant maize lines. This study was to investigate the growth characters at V3 stage of maize, when is very sensitive to waterlogging. Six Korean maize inbred lines were subjected to waterlogging at V3 stage for 30 days. The 30 days waterlogging treatment significantly reduced plant height, number of expanded leaves, and SPAD value, compared with the control plants. SPAD values were significantly different among the six inbred lines, KS140 was the highest. The dry matter accumulation of aerial and root part were significantly decreased by 30 days waterlogging. KS140 was the weightiest among inbred lines. The dry matter of adventitious root showed same trend. Waterlogging treatment significantly reduced to ear length and thickness, grains filling length, grain number per ear, and maize grain. Plant height, SPAD value, and number of fully-expanded leave showed high correlation with maize grain yield, but number of senescent leaves, dry matter of adventitious root and TR ratio did not, suggesting that the former three traits may be good indicator for evaluating 30-day waterlogging tolerance of maize inbred lines. KS164 was the highest yield by increasing of grains filling length and grain number per ear of among waterlogging inbred lines. According to the results, evaluation of maize waterlogging should be consider both early growth characteristics and resilience in the later growth stages.

Drought is one of the detrimental factors that impair plant growth and productivity. In this study, we applied annealing control primer (ACP)-based reverse transcriptase PCR (polymerase chain reaction) technique to identify differentially expressed genes (DEGs) in maize leaves in response to drought stress. Two-week-old maize seedlings were exposed to drought (DT) by suspending water supply. DEGs were screened after 3 days of DT-treated samples using the ACP-based technique. Several DEGs encoding 16.9 protein, antimicrobial protein, hypothetical protein NCLIV_068840, thioredoxin M-type were identified in maize leaves under drought stress. These genes have putative functions in plant defense response, growth and development. These identified genes would be useful for predictive markers of plant defense, and growth responses under drought stress in plants.

This experiment was conducted to comparison study on the productivity for certified varieties of import adaptability of silage corn in Pyeongchang area. Total eight varieties (Gangpyeongok, 31N27, 32P75, 32W86, P3156, P3394, DK 689 및 DK 729) were evaluated. The experimental design was 8 treatment of randomized block with three replications. Corn varieties were cultivated in experimental field of Pyeongchang campus, SNU from 1 May to 2 September, 2015 and plot size was 15㎡. Plant height of 32W86 and ear height of Gwanpyeongok was the highest (p<0.05). Tasseling and silking date was 27 July-3 August and silking occurred after 1-3 day of tasseling. Average day to silking was 92 days and that of 31N27 variety was short (p<0.05). The varieties of DeKalbo Company (DK 689 and DK 729) required more times to silking. Average GDD (growth degree day) of eight varieties was 1,023℃ and P3352 was the lowest GDD. In the trials of resistance evaluation, P3394 was strong in disease, P3156 was the highest in insect. All varieties did not show the lodging and variety of DK 729 showed the highest stay green score (p<0.05). Average dry matter content was 30.77%, it showed higher trend in DM. 32W86 was the highest DM content among the varieties, but there was no significant difference among varieties (p>0.05). The weight per ear was the highest in 32W86 and the lowest in Gwanpyeongok. The ration of ear to whole plant was higher in 32W86 and P3394, but it was not found the significant difference (p>0.05). Average yield of fresh and DM was 59,017 and 13,476 kg/ha, respectively. DK 689 showed higher DM and TDN yield than others, but there was not significant difference (p>0.05). According to results, the difference of productivity was not found among certified variety of import adaptability of silage corn. The varieties Gwanpyeongok, 32W86 and 32P75 would be recommendable in Pyeongchang area for stable cultivation.

Drought is one of important environmental stress for plant. Drought has deleterious effect to plant growth including maize (Zea mays L.) such as vegetative and/or reproductive growth, root extension, photosynthesis efficiency, flowering, anthesis-silking interval (ASI), fertilization, and grain filling. In this study, we screened drought tolerant maize in 21 cultivars from different sources, sixteen NAM parent lines (B73, CML103, CML228, CML247, CML277, CML322, CML333, CML69, Ki11, Ki3, Ky21, M37W, Mo18w, NC350, Oh43 and Tx303), four Korean hybrids (Cheongdaok, Gangdaok, Kwangpyeongok and Pyeonganok) and one Southeast Asian genotype (DK9955). Drought stress (DS) index was evaluated with leaf rolling score at seedling stage and ASI at silking date. The leaf rolling scoring of CML228, DK9955 and Ki11 were determined 1.28, 1.85, 1.86, respectively. However, M37W, Kwangpyeongok, B73 and NC350 were determined over the 3. ASI analysis revealed that CML228, CML103, Cheongdaok, NC350, B73, CML322, Kwangpyeongok and Ki11 are represented less than 5 days under DS and less than 3 days of difference between DS and well-watered (WW), but CML69, Ki3, Pyeonganok, M37W, Mo18w and Gangdaok were represented more than 10 days under DS and more than 8 days of difference between DS and WW. Multi-Dimensional Scaling (MDS) analysis determined CML228, Ki11, and CML322 were regarded as drought tolerance cultivars. Eventually, Ki11 showed genetic similarity with Korean cultivars by QTL analysis and MDS analysis. Ki11 has a potential for development of drought tolerance maize with Korean cultivars.

전 세계적으로 인구가 증가함에 따라 유전자변형(GeneticallyModified; GM) 작물의 생산 역시 가파르게 상승하고 있다.국내에서 GM 작물의 재배가 아직까지는 승인된 바가 없지만식품, 사료, 가공용으로 많은 양이 수입되고 있다. 1. 결과적으로 GMO의 수입이 매년 증가하여 수송과정이나가공과정에서 비의도적인 방출이 발생하며, 주변환경에서 자라고 있는 일반 재배품종으로의 유전자이동 등 국내 자연환경에 미칠 수 있는 영향이 우려되고 있다. 2. GM 작물 중 우리나라에 가장 많은 양이 수입되는 GM옥수수의 비의도적인 방출을 확인하기 위해 2009년 7월부터9월까지 국내 곡물항구와 사료공장을 중심으로 모니터링을 수행하였다. 3. 조사는 주로 개방된 항구의 곡물저장고 지역과 사료공장으로 가는 수송경로에서 옥수수 종자와 자라고 있는 옥수수식물체를 수집하여 진행되었다. 4. PCR 분석을 통해 14개의 GM 옥수수 식물체와 수집된종자를 발아시켜 얻은 식물체 샘플 26개에서 GM 옥수수 유전자가 발견되었다. 5. 낙곡에 의한 GM 옥수수 종자의 유출이나 식물체가 자연환경에서 자라고 있는 것이 우리나라의 생태계에 어떠한 영향을 줄지 예측하기는 어렵지만, 법적으로 GMO를 철저히 관리하도록 되어 있으며, 사회적으로도 수입 GMO를 안전하게 관리하고 있다는 인식을 높이기 위해 주기적인 GMO의 모니터링이 수행되어야 할 것으로 판단된다.

등숙 시기와 이삭 내 위치에 따른 과피 두께 및 립중의 변화를 조사 이들 간의 상관관계를 분석한 결과는 다음과 같다. 등숙 시기별 과피 두께의 변화는 없는 것으로 확인되었다. 따라서 과피 두께는 수정 후 18일 전에 결정되는 것으로 판단되며 식미가 우수한 찰옥수수 품종 육성을 위한 과피 두께 조사는 풋이삭 수확 적기뿐 만 아니라 이 그 후에 실시하여도 풋이삭 수확 적기와 동일한 관측치를 획득할 수 있을 것이라 판단된다. 립중은 최초 조사기인 수정 후 18일에서부터 계속 증가하다가 35일경 이후 부터는 비슷한 무게를 유지하였으며 등숙 시기별 과피 두께의 변화와는 통계적 상관 관계가 없는 것으로 확인되었다. 따라서 전분 축적과 종자의 성숙을 통한 종자 부피의 증가와 과피 두께 변화는 서로 연관성이 없는 것으로 판단된다. 이삭 내 위치에 따라 하부에서 상부로 갈수록 과피 두께 및 립중의 평균은 감소하는 경향이었으며 이들의 표준편차는 중앙부에서 안정되고 작게 조사되었다. 또한 이삭 내 위치에 따른 과피 두께 및 립중의 평균간에는 두 품종 모두 정의 상관 관계가 있음을 확인하였다. 이로서 찰옥수수 품종 육성과정에서 과피 두께를 위한 시료의 채취는 이삭 중앙부로부터 샘플을 취하는 것이 변이가 적고 평균적인 관측치를 얻을 수 있을 것으로 기대된다.