본 시험은 논으로부터 밭으로 윤환한 2년차인 답전윤환밭과 연속밭에 풋옥수수 찰옥4호 등 8품종을 사용하여 윤환밭과 연속밭의 병충해 발생, 생육 및 수량특성 차이 구명은 물론 풋옥수수의 체계적인 유기농 답전윤환 재배기술을 위한 기초자료를 확립하고자 수행한 결 과는 다음과 같다. 유기농 답전윤환 시 주요 병해는 전반적으로 연속밭에 비해 윤환밭에서 발병률이 높았으며, 시험품종 중 저항성 품종으로 발병률이 2% 미만인 흑진주찰과 대학찰 로 판단되었다. 유기농 답전윤환 시 주요 충해인 조명나방 유충 피해는 전반적으로 연속밭 에 비해 윤환밭에서 피해주율이 높았으며, 시험품종 중 저항성 품종으로는 피해주율이 낮 은 찰옥4호와 흑점2호로 판단되었다. 유기농 답전윤환 시 수량은 윤환밭에서 연속밭의 85 % 수준으로 감소하였으며, 답전윤환밭에서는 찰옥4호가 789.0 kg/10a로 가장 수량이 많았 다. 내병성, 내충성, 수량을 종합 평가하면 유기농 답전윤환 시 적합 품종으로는 찰옥4호, 흑진주찰, 흑점2호로 판단된다.

‘Sinhwangok’, a new maize F1 hybrid (Zea mays L.), is developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2015. The high-yielding hybrid, named ‘Sinhwangok’ was bred by crossing between two inbred lines, ‘KS178’ and ‘KS145’. It is a yellow dent maize hybrid. After advanced yield trial of ‘Sinhwangok’ in Suwon for two years, regional yield trial was subsequently carried out for evaluation of its growth and yield at three different locations from 2012 to 2015. The days to silking of ‘Sinhwangok’ are 74. The plant height of ‘Sinhwangok’ is 241cm, similar to ‘Jangdaok’, and its ear height ratio is 51%, similar with that of ‘Jangdaok’. It has resistance to lodging. The number of ear per 100 plants is 96. The ear length of ‘Sinhwangok’ is 17cm, shorter than that of ‘Jangdaok’. The weight of 100 seeds of ‘Sinhwangok’ is 34.1g, similar to that of ‘Jangdaok’. It has moderate resistance to southern leaf blight (Bipolaris maydis). It has moderate resistance to European Corn Borer (Ostrinia nubilalis). The grain yield (8.9 ton/ha) of ‘Sinhwangok’ was 15% higher than that of ‘Jangdaok’. The seed production of ‘Sinhwangok’ was acceptable due to a good synchronization of flowering period during crossing between the seed parent, KS178, and the pollen parent, KS145, in Yeongwol and F1 seed yield was 2.3 ton/ha. ‘Sinhwangok’ would be a suitable cultivar to all plain area in Korea.

We collected 32 maize inbred lines from eastern cereal and oilseed research center in Canada to develop new maize varieties. We also evaluated genetic diversity, genetic relationships, and population structure using 35 SSR markers. A total of 269 alleles were revealed in 35 loci with an average of 7.69 and a range between 3 and 15 alleles per locus. The genetic diversity values varied from 0.176 to 0.889 with an average of 0.691. The polymorphic information content varied from 0.171 to 0.879 with an average of 0.659. Population structure analysis indicated that 32 Canadian maize inbred lines comprised four major groups and one admixed group based on a membership probability threshold of 0.80. The four major groups contained 13, 2, 5 and 2 maize inbred lines, respectively. From genetic relationships analysis, the all inbred lines were divided into three main groups at 26% genetic similarity. Group I included 22 inbred lines, and Group II included 9 inbred lines. Group III consist of only one inbred line. The results in this study would be useful for the improvement and development of new cultivars, planning crosses for hybrids or development of inbred line in maize breeding program

We screened the drought tolerant maize using seventeen maize genotypes from different sources, nine inbred genotypes from United States Department of Agriculture (USDA) (B73, CML103, CML228, CML277, CML322, CML69, Ki3, Ki11, and NC350), three Southeast Asian genotypes (DK9955, LVN-4, and 333), and five Korean hybrids (Cheongdaok, Gangdaok, Ilmichal, Kwangpyeongok, and Pyeonganok). We evaluated anthesis-silking interval (ASI), leaf senescence (LS), ears per plant (EPP), tassel length (TL), and fresh weight (FW) at silking date. According to ASI and LS examination, CML103 and Kill were drought tolerant genotypes, wheareas Ki3 and 333 were drought susceptible. EPP, TL, and FW differed according to drought resistance. Grain yield was correlated strongly with ASI, but moderately with LS. Difference in ASI between drought-stressed (DS) and well-watered (WW) conditions was less than three days in CML228, CML103, Cheongdaok, NC350, B73, Ki11, CML322, and Kwangpyeongok, whereas that of Ki3, Pyeonganok, and Gangdaok was more than 6.5 days. We concluded that CML228, CML103, Cheongdaok, NC350, B73, Ki11, CML322, and Kwangpyeongok are drought tolerant genotypes, whereas Ki3, Pyeonganok, and Gangdaok are drought susceptible.

The objective of this study was to find a rapid determination of the hot air stress in maize (Zea mays L.) leaves using a portable chlorophyll fluorescence imaging instrument. To assess the photosynthetic activity of maize leaves, an imaging analysis of the photochemical responses of maize was performed with chlorophyll fluorescence camera. The observed chlorophyll imaging photos were numerically transformed to the photochemical parameters on the basis of chlorophyll a fluorescence. Chlorophyll a fluorescence imaging (CFI) method showed that a rapid decrease in maximum fluorescence intensity (Fm) of leaf occurred under hot air stress. Although no change was observed in the maximum quantum yield (Fv/Fm) of the hot air stressed maize leaves, the other photochemical parameters such as maximum fluorescence intensity (Fm) and Maximum fluorescence value (Fp) were relatively lowered after hot air stress. In hot air stressed maize leaves, an increase was observed in the nonphotoquenching (NPQ) and decrease in the effective quantum yield of photochemical energy conversion in photosystem II (Φ PSII). Thus, NPQ and ΦPSII were available to be determined non-destructively in maize leaves under hot air stress. Our results clearly indicated that the hot air could be a source of stress in maize leaves. Thus, the CFI analysis along with its related parameters can be used as a rapid indicating technique for the determining hot air stress in plants.

This study aimed at improving the method of oil cake application in maize. The experiment was conducted during 2 years at NAS (National Institute of Agricultural Sciences) experimental field, located in Wanju-kun, Jeollabuk-do. Growth factors and nutrient use efficiency were evaluated depending on oil cake application depth, placement, and application rate. Difference in oil cake application method and depth was tested in 2012 and different placements of oil cake application were compared in 2013. Plant height, SPAD value, and dry weight of stem and corn were investigated. SPAD value, dry weight of stem and corn were significantly higher in oil cake banding treatment (OB5, 5 cm depth) as compared to others application methods, i.e. spreading (OS0), deep banding (OB10) and banding + spreading (OB5S). In addition, dry weight of stem and corn of banding treatments (OBL, OBLL) on rhizosphere and in between row (OBR) were higher than spreading treatment (OSP). Furthermore, in case of reduced application rate in additional fertilization did not decrease dry weight of corn and increased nutrient use efficiency. Therefore, it is concluded that banding application in 5 cm-depth and rhizosphere can improve growth and nutrient use efficiency in maize production.

This study was carried out to evaluate the proximate contents and compositions of amino acids and fatty acids in Korean 6 dent, 2 intermediate, and 3 semiflint maize (Zea mays L.) hybrids. The protein content of 11 Korean maize hybrids ranged from 9.0% (Pyeonggangok) to 11.5% (Jangdaok). The crude fat content varied from 4.0% (Pyeonggangok and Yanganok) to 5.6% (Kwangpyeongok), and the crude ash content was 1.3 (Jangdaok) ~ 1.6% (Cheonganok). Total starch contents of maize hybrids were determined in the range of 51.4% (Jangdaok) to 70.9% (Cheonganok). Major amino acid in maize varieties were glutamic acid (27.28~28.68%) and followed by proline, alanine, and aspartic acid. Fatty acid were mainly composed of oleic acid (C18:1, 23.55~31.47%) and linoleic acid (C18:2, 47.55~56.64%) in maize hybrids. Cheonganok, Cheongdaok, and Kwangpyeongok had high oleic acid composition among Korean maize hybrids. Also, Gangdaok and Kwangpyeongok had high composition of saturated fatty acid. Because kernel composition affects maize quality, it is important data for the maize breeding program and food processing.

‘Daanok’, a new maize F1 hybrid (Zea mays L.), is developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2013. The high-yielding hybrid, named ‘Daanok’ was bred by crossing between two inbred lines, ‘KS174’ and ‘KS175’. It is a yellow semi-flint maize hybrid (Zea mays L.). After preliminary yield trial and advanced yield trial of Daanok in Suwon for two years, regional yield trial of that was subsequently carried out for evaluation of its growth and yield at three different locations from 2011 to 2013. The silking date of Daanok is earlier than that of the check hybrid, ‘Jangdaok’. The plant height of Daanok is 229cm, similar to Jangdaok, and its ear height ratio is similar with that of Jangdaok. It has resistance to lodging. There are much of the No. of ear per 100 plants. The ear length of Daanok is similar with that of Jangdaok. The weight of 100 seeds of Daanok is the same with that of Jangdaok. It has strong resistance to northern leaf blight (Exserohilum turcicum) and southern leaf blight (Bipolaris maydis). It has strong resistance to ear lot. It has moderate resistance to corn borer. The grain yield (7.34 ton/ha) of Daanok was 23% higher than that of Jangdaok. The seed production of Daanok has gone well due to a good synchronization of flowering period during crossing between the seed parent, KS174, and the pollen parent, KS175, in Yeongwol and F1 seed yield was 2.38 ton/ha. Daanok would be a suitable cultivar to all plain area in Korea.

In order to develop a core set and new corn variety in Korea, we evaluated the morphological characteristics of 194 maize accessions by examining eight quantitative characteristics. On the evaluation of quantitative traits for 194 maize accessions, they showed the morphological variations in tassel length (35.1±5.0 cm), plant height (226.1±33.7 cm), ear height (86.3±22.6 cm), stem diameter (2.3±0.6 cm), leaf width (9.3±1.1 cm), ear length (14.5±2.4 cm), ear row number (14.1±1.9 row), and 100 kernel weight (24.9±4.4 g). The results of principal component analysis (PCA) indicated that the tassel length, plant height, and ear height greatly contributed to positive direction on the first principal component axis. One-hundred kernel weight contributed to negative direction on the second principal component axis. Thus these morphological characteristics, which contributed greatly in the first and second principal components, might be useful for discrimination among 194 maize accessions. In our study, seven accessions, such as IT026357, IT026441, IT027321, IT033271, IT033591, IT033597 and IT124273, particularly were measured high on yield-related traits. Consequently, the 194 maize accessions used in this study could be used as promising materials for maize breeding programs such as development of new hybrid in Korea.

Anther culture is useful and significant tool for producing haploid or doubled haploid (DH) plants in crop breeding system. Androgenesis is the way of inducing haploid and DH plants from anther (immature pollen) or microspore culture. In vitro androgenesis is efficient technique for introducing complete homozygous lines in one generation, thus less time and expense could be necessary than conventional plant breeding. In maize, anther culture is important system for shortening the breeding cycle and enhancing selection efficiency. Anther culture technique is also applicable to various researches such as molecular genetics, genetic engineering, genomics, and plant biotechnology. We review the past and present studies on anther culture and provide useful information for future researches on androgenesis in maize. The combination of androgenesis with other techniques such as molecular breeding and biotechnology is producing a variety of variety of maize species. In addition, we suggest strategy to develop androgenesis technique adapted to Korean research environment.

This study was conducted to evaluate maize downy mildew resistance using spreader row technique in Cambodia. A total of forty maize lines were used in this experiment. Seven Korean varieties and seven breeding lines showed high infection rates (80~100%) and highly susceptible (HS) to downy mildew disease in both spring and fall. Also most of nested association mapping (NAM) parent lines were highly susceptible (HS). Meanwhile three inbred lines, Ki3, Ki11, and CML228, showed highly resistant (HR) or resistant (R) in spring and moderately resistant (MR) in fall. These three lines were already known as resistant inbred lines against downy mildew disease. It appears that spreader row technique was suitable for selection of maize downy mildew resistance in Cambodia. The incidence of downy mildew was influenced by weather conditions, especially relative humidity and temperature. Among several inoculation methods to screen for downy mildew resistance, this spreader row technique is effectively and easily used in the field of Southeast Asia.

This paper aims to analyze inequality of maize self-sufficiency rate among countries in 1970-2011. Utilizing sub-group consistency of Generalized Entropy and Atkinson inequality index, the estimated maize self-sufficiency rate inequality is further decomposed into two steps’ separate country groups. First, lower and upper income groups and then lower, lower middle, upper middle and high income groups are used based on the national classification of the world bank. It is inferred that 1980s’ policy intervention and 1990s’ Uruguay Round negotiations have different effect on the inequality among four different country groups.

Drought stress has detrimental effects on the seedling development, vegetative/ reproductive growth, photosynthesis, root proliferation, anthesis, anthesis-silking interval (ASI), pollination and grain yield in maize. Typically, two weeks before silking through pollination are an important time in maize life. Here we reviewed the effects of drought stress on growth, physiological/ molecular researches for drought tolerance, and breeding to genomics in maize. Drought stress during kernel development increases leaf dying and lodging, decreases grain filling period and grain yield. Physiological factors of drought stress/ effects are water content, water deficits, and water potential. Nowdays molecular marker assisted breeding method is becoming increasingly useful in the improvement of new germplasm with drought stress tolerance.

반이면 교잡을 통해 얻어진 36개의 F1 교잡종들에 대하여 수량 및 농업관련 형질에 대하여 조사하였다. 36개 교배조합 의 F1과 교배친의 잡종강세를 조사한 결과, F1의 잡종강세 정 도는 종실수량에서 156%로 가장 컸고, 100립중이 가장 작은 7%로 나타났다. 농업형질에 의한 교배친들 사이의 표현형적 거리는 육성된 계보와 차이가 있었으며, 농업형질만으로 유전 적 거리를 측정하는 것은 한계가 있었다. SSR 분석에 의한 유전적 거리와 농업형질과의 상관을 확인하기 위하여 9개의 자식계통에 대한 92개의 SSR primer를 확인한 결과, 육성 계 보에 의한 유연관계를 명확하게 나타내지 못하여 표현형적 거리와 SSR 마커에 의한 유전적 거리에서도 유의성을 찾을 수 없었다. 본 연구에서는 옥수수 종실수량과 SSR 분석을 통 한 유전적 거리 사이의 유의성이 없었다. 따라서 종실수량과 정의 상관을 보이는 9개의 primer 조합을 선발하였다. 9개의 SSR primer들을 이용한 계통유연관계를 분석에서 옥수수 계 통들의 계보와 선발된 SSR을 이용한 유전적 거리는 연관성 을 찾을 수 없었지만, 종실수량과 선발된 9개의 SSR primer 를 이용한 유전적 거리와는 고도의 정의 상관을 보였다 (R2=0.703**). 선발된 SSR primer를 이용한 유전적 거리와 교잡종의 주요 농업형질의 상관 분석 결과, 교잡종 자체의 수 량구성의 모든 요소뿐만 아니라 간장, 착수고도 유의성을 보 였고, 평균에 대한 잡종강세와는 종실수량이 정의 상관을 보 였다. 본 연구에서 선발한 9개의 SSR primer들은 옥수수 육 종연구에서 교배조합 구성을 위한 잡종강세 예측에 도움을 줄 것으로 생각된다.

The maize production in South-eastern Asian countries showed a continuous increase with increasing poultrylivestock from the beginning of the 1990s to early 2010. Also the need for a new variety development of each contries was increased rapidly in the same period. Single-Cross hybrid varieties have been developed and supplied from 2001 instead of multi-cross maize varieties since 1992 in Indonesia. In Cambodia, CP group is mainly manufacturing feeds with most of the forage maize from farmers who are growing its seeds from the company. Cambodian main cultivars are varieties of multinational corporations such as DK8868 from Monsanto, NK6326, NK7328 from Syngenta and CP333 from CP group including local business company. Vietnam is the main maze importing country in South-Eastern Asia which had imported 13 times scale of amount compared to exports in average from 1990 to 2011. Vietnamese government has developed a range of varieties for improving their efficiency in production, such as the LVN-10 with political investments. Their production has been reached to 80% of the total. According to the 2012 MIFAFF (Ministry for Food, Agriculture, Forestry and Fisheries) data in Korea, domestic edible maize cultivation area was approximately 15,000ha. It showed 74,399 tons of production, 3.8% of food self-sufficiency in maize and around 0.9% of grain self-sufficiency rate. The consumption of grain is mostly rely on imports in Korea. To overcome the limit of the domestic seed market and increase maize self-sufficiency, the need to develop maze varieties for world-class is increasing at present through analyzing the market trend and prospect of the seed industry in South-eastern Asia

The maize genome is complex with exceeding the levels of intra-specific variation, repetitive DNA content, and allelic content observed between many species. Because of tremendous diversity and variants, maize is considered as a forefront crop development and estimation of molecular markers for agricultural trait in genetics and breeding. Using quantitative trait loci (QTL) and marker assisted breeding (MAS), molecular breeders are able to development of drought tolerance and grain yield in maize genotype. To study QTL congruency, a meta QTL analysis including results from eight-teen QTL publications for grain yield and drought tolerance were considered. Among them, we assembled 420 QTLs for abscisic acid (ABA) concentration, anthesis silking interval (ASI), days to flower, days to silk, ear number, kernel number, grain number and grain yields, involved in drought tolerance and grain yield. The meta QTL analysis revealed significant evidence for linkage of these traits to 39 different segments as candidates regions on maize genome. A total of 571 marker was selected as QTL or integrated QTL markers for narrowing down the QTL region into specific functionally relevant candidates. The results of meta QTL analysis helped to refine the genomic regions of agricultural traits, interest described and provided the closest flanking markers.

Assessing genetic diversity, population structure, and linkage disequilibrium is important in identifying potential parental lines for breeding programs. In this study, we assessed the genetic and phenotypic variation of 174 normal maize (Zea mays) inbred lines and made association analyses with respect to nine agronomical traits, using 150 simple sequence repeats (SSR). From population structure analysis, the lines were divided into three groups. Association analysis was done with a mixed linear model and a general linear model. Twenty one marker-trait associations involving 19 SSR markers were observed using the mixed model, with a significance level of P<0.01. All of these associations, as well as 120 additional marker-trait associations involving 77 SSR markers, were observed with the general model. Two significant marker-trait associations (SMTAs) were detected at P ≤ 0.0001. In the mixed linear model, one locus was associated with water content, two loci were associated with 100-kernel weight, setted ear length, ear thickness and stem thickness; three loci were associated with ear height, four loci were associated with total kernel weight and five loci were associated with plant height. These results should prove useful to breeders in the selection of parental lines and markers.

다평옥은 다수성 종실용 옥수수 품종 개발을 위하여 2010 년에 농촌진흥청 국립식량과학원에서 자식계통 KS158과 KS155를 교잡하여 육성한 다수성 단교잡종이다. 다평옥의 종피색은 황색이며 입질은 마치종이다. 2006～2007년까지 2 년 동안 생산력검정시험을 거쳐 2008～2010년까지 3년 동안 수원 등 3지역에서 지역적응시험을 실시하였다. 그 결과 우수 성이 인정되어 2010 농작물 직무육성 신품종으로 결정되었고 다평옥으로 명명하였다. 다평옥의 출사일수는 장다옥과 같다. 간장은 장다옥과 비슷하며 착수고율은 장다옥과 같다. 도복은 장다옥 정도로 강한 것으로 나타났다. 이삭길이는 장다옥보다 다소 작으며 100립중은 장다옥보다 가볍다. 깨씨무늬병과 그 을음무늬병에는 강한 편이다. 검은줄오갈병, 이삭썩음병 및 조명나방 저항성은 중 정도를 보인다. 다평옥의 종실수량은 8.6 톤/ha로 장다옥보다 8% 많았다. 4 : 1(모본 : 부본) 재식 비율로 동시 파종하여 채종 시험한 결과 모본 출사기와 부본 화분비산기간이 일치하였으며 채종수량은 2.8 톤/ha이었다. 다평옥은 전국적으로 재배가 가능하다(품종출원등록번호: 제 4969호).

본 연구는 12개의 색소 및 비색소옥수수 계통들에 대하여 300개의 SSR마커를 이용하여 유전적 다양성, 계통유연관계 및 집단구조 분석을 실시하였다. 유전적 다양성 분석 결과, 300개의 SSR primer들은 색소 및 비색소옥수수 12계통들에 서 총 1,331개의 대립단편을 증폭시켰으며, SSR primer당 대 립단편들은 최소 2개에서 최대 10개까지 나타나 평균 4.44개가 증폭되었다. MAF는 0.25에서 0.92의 범위로 나타났고, 평균값은 0.48을 나타내었다. 총 1,331개의 대립단편 중에서 221개의 대립단편들은 색소옥수수 계통들에서 특이적으로 나 타났고, 408개의 대립단편은 비색소옥수수 계통들에서 특이 적으로 나타났으며, 나머지 702개의 대립단편들은 색소 및 비색소 계통들에서 공통으로 확인되었다. 그리고 총 163개의 SSR 마커에서 색소옥수수 특이적 대립단편이 확인되었다. 집 단구조에 대한 분석 결과에서 12개의 색소 및 비색소옥수수 핵심집단 계통들은 groups I, II, III, admixed group으로 구 분되었다. 본 연구결과는 옥수수 육종연구에서 색소 및 비색 소옥수수 계통들의 식별에 대한 유용한 정보를 제공할 것이다

The objective of this study was to evaluate the drought tolerance in maize seedling using leaf rolling. Nineteen maize resources, seven Nested Association Mapping parents lines, six Korean commercial cultivars, and six Southeast Asia commercial cultivars, were used to examine drought tolerance. The leaf rolling scores were measured on each leaf in three stress conditions with moderate drought (10%), severe drought (7%), and extreme drought (5%). Generally leaf rolling score of seedlings increased at the lower soil water potentials (5~7%). As a result, drought-tolerant cultivars showed lower leaf rolling score (below 2.5) than the drought sensitive cultivars (above 3.5). Nine varieties, NK4043, CML322, DK9955, NK4300, Ki11, DK8868, CML228, LVN99, and LVN10, have been selected for tolerance to drought stress. These results suggest that the leaf rolling score in maize seedling has been made available to indirect index for drought tolerance.