Chalok3, a new waxy corn hybrid was developed at the National Crop Experiment Station, RDA in 2001. It is a single cross hybrid, which was crossed between KW35 as a seed parent and KW7 as a pollen parent. Chalok3 was 73 days in days to silking and eight d

A single cross, Pungmiok is yellow dent hybrid maize (Zea mays L.) developed by the corn breeding team at the National Crop Experiment Station (NCES), RDA in 2002. This hybrid, which has a high yield of dry matter, total digestible nutrients (TDN), is mad

A single cross, Cheonganok, is a yellow semi-flint hybrid maize (Zea mays L.) developed by the corn breeding team at the National Crop Experiment Station (NCES), RDA in 2002. This hybrid, which has a high yield of dry matter, total digestible nutrients (T

Danok3, a sweet corn hybrid that matures early was developed by the corn breeding team at the National Crop Experiment Station (NCES), RDA in 2001. Inbred KSS2 derived from Golden Bantam was used as the seed parent of Danok3, and inbred KSS22 derived from

옥수수 종자의 활력을 향상시키는 방법을 모색하기 위하여 마치종 옥수수, 단옥수수, 초당옥수수의 건전종자와 인위적으로 노화처리하여 활력이 낮은 종자를 수분함량이 50, 75, 100, 125%인 vermiculite와 섞어 25℃ 에서 24시간 matriconditioning하였다. 처리된 종자를 토양에 파종하여 25℃ 와 co]d test(10℃ 에서 7일 처리 후 25℃ 에서 7일 처리)조건에서 종자활력을 조사하여 matriconditioning에 알맞은 vermiculite의 수분함량을 구명하였고, 또 침종시 종자의 당과 전해질의 누출량, α -amylase 활성, DNA 및 가용성 단백질 함량을 조사하여 mariconditioning할 때 종자의 생리적인 변화를 조사하였으며, 그 결과를 요약하면 다음과 같다. 1. 옥수수의 출아율, 출아속도, 유묘생장은 마치종 ＞ 단옥수수 ＞초당옥수수의 순으로 작았다. 건전종자가 노화종자보다 출아율, 출아속도, 유묘생장이 좋았고. α -amylase 활성, DNA 및 가용성 단백질 함량은 높았으나 당과 전해질의 누출은 적었다. 2. Matriconditioning은 25℃ 에서 발아할 때 마치종과 단옥수수의 건전종자의 출아율에는 영향을 미치지 않았으나 활력이 낮았던 초당옥수수 건전종자와 모든 genotype의 노화종자는 matriconditioning할 때 수분함량이 높을수록 출아율이 증가하였다. Cold test에서는 25℃ 와 같은 경향이었으나 출아율이 더 낮았다. 3. 출아속도는 단옥수수 건전종자는 25℃ 와 cold test에서 모두 matriconditioning의 영향을 받지 않았지만 다른 종자는 25℃ 와 cold test에서 모두 matriconditionig 할 때 수분 함량이 높을수록 출아속도가 빨랐다. 4. 유아장과 유아중은 cold test에서 matriconditioning의 영향이 없었던 초당옥수수의 건전종자와 노화종자를 제외한 다른 종자는 모두 25℃ 와 cold test에서 수분함량이 높을수록 유아장과 유아중이 증가하였다. 5. 종자의 당 누출량은 마치종 ＜단옥수수 ＜초당옥수수의 순으로 많았다. 마치종은 건전종자와 노화종자 모두 당 누출량이 적었다. 단옥수수는 노화종자의 당 누출량이 건전종자보다 다소 많았고, matriconditioning할 때 수분함량이 증가할수록 당누출량은 다소 감소하였다 초당옥수수는 노화종자가 건전종자보다 당 누출량이 현저히 많았으며, 건전종자는 50%, 노화종자는 100%까지 matriconditioning처리할 때 수분 함량이 높을수록 당 누출량은 감소하였다. 6. 종자의 전해질 누출량(침지액의 전기전도도)은 마치종 ＜단옥수수 ＜초당옥수수의 순으로 높았고, matriconditioning할때 수분함량이 높을수록 전해질의 누출량은 감소하였다. 7. α -amylase활성은 단옥수수 ＜마치종＜초당옥수수의 순으로 높았다. 모든 옥수수 genotype에서 matriconditioning할 때 수분 함량이 높을수록 α -amylase활성이 증가하였다. 8. DNA와 수용성 단백질 함량은 초당옥수수 ＜마치종 ＜단옥수수의 순으로 높았다 모든 genotype의 건전종자와 노화종자는 matriconditoining할 때 수분함량이 높을수록 DNA와 수용성 단백질 함량이 증가하는 경향이었다.

This paper is intented to present a information of various aspects of quality related characteristics and standards for grades in maize. Maize is world's one of the three most popular cereal crops and a primary energy supplement and can contribute up to 30, 60, and 98% of the dairy diet's protein, net energy, and starch, respectively. Maize is also processed into industrial goods by wet or dry milling. Sweet corn is a leader among vegetable crops and its production for fresh or processing markets is a major industry in many countries. Over the years, the combined efforts of breeders and geneticists, biochemists, food scientists, and others have helped bring us to the point where we understand issues related to sweet corn quality. Traditional criteria for selecting corn hybrids have been based primarily on agronomic factors, including grain production, disease resistance, drought tolerance, and storage characteristics. Little emphasis has been placed on the quality and nutritional values of corn. Although there is widespread interest for value-enhanced corns have increased tremendously in the last five years, there is limited information available on the production and comparing the quality attributes of specialty grains with those of normal yellow dent corn. Most countries have developed national maize standards, aiming to provide a framework for trade, both internal and external. Where trading involves direct choice and price negotiation in front of the commodity, grading standards are rarely employed; quality is assessed visually and is influenced by end-use, and the price is determined more by local rather than national factors. The use of an agreed standard will provide an unambiguous description of the quality of the consignment and assist in the formation of a legally-binding contract. Standards can also be seen to protect consumers rights through setting limits to the amount of unsuitable or noxious material.

MITEs (miniature inverted-repeat transposable elements) are one of the major transposable elements in maize. We have applied MITE-AFLP technique to study the genetic diversity and genetic relationship among 25 elite maize inbred lines. While MITE-AFLP fra

Dehydrins (LEA Dll proteins) are one of the typical families of plant proteins that accumulate in response to dehydration, cold stress, abscisic acid, or during seed maturation. A 1.3-kb cDNA was cloned from a cDNA expression library of 5-day-old germinating maize scutellums under drought stress. The deduced protein sequence indicated a dehydrin gene encoding SK3 LEA protein typically expressed during cold acclimation, but not by drought stress in barley and wheat. Thus, it was named maize DEHYDRIN2 (ZmDhn2). It accumulates rapidly and highly in drought-stressed scutellum and leaf tissues at any stage, but not under cold stress. ZmDhn2 gene was transformed into Arabidopsis thaliana for functional analysis under drought condition. From electrolyte leakage test, no significant difference showed between wild type and transformants under normal growth condition, but the leakage level of electrolyte in wild type plants was about 3 times as high as that in the transformed plants under drought stress. It suggests that ZmDHN2 playa role in increasing drought tolerance.

Major characteristics of new Waesungri maize inbred line has multi-tiller and ears: five to six tillers and seven to eight ears per plant and flowering date of Waesungri was delayed about 18 and 24 days compared to Mo17 U.S line and IK4 Korean local lines, respectively. Number of ears, fresh and dry weight per plant were significantly different among all tested hybrids including Waesungri/Sinkihong hybrid under different planting times and densities. Especially, both fresh and dry weight of IK1/FR140//Waesungri F1hybrid were significantly higher at high planting density. In kernel weight per unit area, Wnesungri/Sinkihong hybrid was high at high density and IK1/FR140//Waesungri hybrid was high at low planting density. As results of analysis of variance, flowering date was shown a significantly different both planting times and varieties, while other characters including stem height were shown very variable in interactions with enviromental factors.

Field experiment was conducted during 1993-94 season to determine the pattern of nutrient uptake and productivity of maize/sweet potato intercropping system. Four levels of nitrogen (0, 50, 100 and 150kg N ha-1 ) and four levels of potassium (0, 40, 80 and 120kg K2 O ha-1 ) formed treatment variables. Plants were sampled periodically to determine dry matter and tissue concentrations of N and K in the individual plant components of intercropped maize and sweet potato. Nitrogen and potassium fertilizer did not interact significantly to nutrient uptake by any plant parts of intercropped maize and sweet potato. But application of N fertilizer independently enhanced N uptake in all the plant parts of maize and sweet potato. The uptake of N in leaf, leaf sheath, stem, husk, and cob of maize increased upto 90 days after planting (DAP) but grain continued to accumulate N till its maturity. Sweet potato exhibited a wide variation in N uptake pattern. Sweet potato leaf shared the maximum uptake of N at 50 DAP which rapidly increased at 70 DAP and then declined. Declination of N uptake by petiole and stem were observed after 120 DAP whereas N uptake by tuber increased slowly upto 90 DAP and then rapidly till harvest. Rate of applied K had very little effect on the uptake patterns in different components of intercropped maize. Pattern of K uptake by leaf, petiole and stem of sweet potato showed almost similar trend to N uptake. But uptake of K by tuber increased almost linearly with the K application. Pattern of N and K uptake by grain and tuber paralleled the grain yield of maize and sweet potato respectively. Intercropped productivity of maize and sweet potato found to be better by the application of 100kg N and 120 kg K2 O ha-1

In nature, plant diseases, insects and parasites (hereafter called as "pest") must be co-survived. The most common expression of co-survival of a host crop to the pest can be tolerance. With tolerance, chemical uses can be minimized and it protects environment and sustains host productivity and the minimum pest survival. Tolerance can be applicable in all living organisms including crop plants, lifestocks and even human beings. Tolerant system controls pest about 90 to 95% (this pest control system often be called as horizontal or partial resistance), while the use of chemicals or selection of high resistance controls pest 100% (the most expression of this control system is vertical resistance or true resistance). Controlling or eliminating the pests by either chemicals or vertical resistance create new problems in nature and destroy the co-survial balance of pest and host. Controlling pests through tolerance can only permit co-survive of pests and hosts. Tolerance is durable and environmentally-friend. Crop cultivars based on tolerance system are different from those developed by genetically modified organism (GMO) system. The former stabilizes genetic balance of a pest and a host crop in nature while the latter destabilizes the genetic balance due to 100% control. For three decades, the author has implemented the tolerance system in breeding maize cultivars against various pests in both tropical and temperate environments. Parasitic weed Striga species known as the greatest biological problem in agriculture has even been controlled through this system. The final effect of the tolerance can be an integrated genetic pest management (IGPM) without any chemical uses and it makes co-survival of pests in nature.in nature.