• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.662-669
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• 1995

To clarify the effect of temperature during ripening on grain quality, rice plant which was grown under normal natural conditions untill heading stage was subjected various temperature regimes during grain filling stage. Three varieties, Odaebyeo, Hwaseongbyeo and Dongjinbyeo were used. Grains on primary and secondary-rachis branches were harvested seperately and measured specific gravity, grain size and weight. The optimum daily temperature for grain filling of rice during ripening period was about 22$^{\circ}C$ and grain filling under alternating temperature(26/18$^{\circ}C$, day /night) was better than constant temperature (22 /22$^{\circ}C$) based on 1, 000-grain weight and yield. Grain size based on volume per grain was smallest under the constant temperature of 22 /22$^{\circ}C$. The size of secondary-rachis branches was smaller than primary-rachis branch. The difference in size between primary and secondary-rachis branches was biggest in Hwaseongbyeo, followed by Odaebyeo and Dongjinbyeo. The temperature regimes treated did not influence the grain size difference between branches so much. The 1000-grain weight was lighter under high temperature than low temperature in Odaebyeo, but reversed tendency was observed in Dongjinbyeo of secondary rachis-branches.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.2
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• pp.85-92
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• 1993

This study was investigated on the morphological characteristics of rice grain as affected by three fertilizer application treatments. Of no-nitrogen, optimum nitrogen, and heavy nitrogen without potassium in three regions of Suweon (Mid-West Plain Zone), Ichon(Mid-Inland Plain Zone), and Kyehwado(South-charyung Mts. Plain Zone) with four varieties, i.e., three Tonsil types(Geumgangbyeo, Milyang 23, and Chilseongbyeo) and one japonica type(Chucheongbyeo, Akibare in Japanese name). The results obtained were as follows: The increase of nitrogen application caused an increase of grain length in rough rice and grain width in milled rice, resulting in a decrease of the width/thickness ratio in milled rice. The width and thickness of rice grain produced in Kyehwado were smaller than those in the other regions. Therefore, the ratio of length/width and length/thickness in rice grain produced in Kyehwado was larger. The one thousand grain weight of rice was heavier at the optimum nitrogen level than at the no-nitrogen and heavy nitrogen without potassium treatment levels. The weight percentage of hull in rough rice grain decreased in accordance with the increase of nitrogen application, while the weight percentage of bran in brown rice was constant. This suggested that for the normal development of rice grain a constant ratio of bran is needed. The morphological change of rice grain by fertilizer treatments and the change of region cultivated could not be distinguished from the native characteristics of the variety. Other grain characteristics were discussed in view of treatment and regional effects.

• Journal of Life Science
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• v.25 no.8
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• pp.925-931
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• 2015

We performed a molecular marker-based analysis of quantitative trait loci (QTLs) for traits that determine the quality of the appearance of grains, using 120 doubled-haploid (DH) lines developed by another culture from the F1 cross between ‘Cheongcheong’ (Oryza sativa L. ssp. Indica) and ‘Nagdong’ (Oryza sativa L. ssp. Japonica). The traits studied included length, width, and thickness of the grains, as well as length-to-width ratio and 1,000-grain weight. The objective of this study was to determine the genetic control of these traits in order to formulate a strategy for improving the appearance of this hybrid. Within the DH population, five traits exhibited wide variation, with mean values occurring within the range of the two parents. Three QTLs were identified for grain length on chromosomes 2, 5, and 7. Three QTLs were mapped for grain width on chromosome 2: qGW2-1, qGW2-2, and qGW2-3. Six chromosomes were identified for the grain length-to-width ratio; four of these were on chromosome 2, whereas the other two were on chromosomes 7 and 12. One QTL influencing 1,000-grain weight was identified and located on chromosome 8. The results presented in the present study should facilitate rice-breeding, especially for improved hybrid-rice quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.222-226
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• 2004

This study was conducted to measure the major agronomic characteristics of 85 local varieties of perilla at Chungbuk Agricultural Research and Extension Services in 2001. Perilla accessions examined were classified into three maturity groups, i.e, early, medium, and late maturity group of 19 (23％),57 (67％), and 9 (10％) accessions, respectively. The early and late maturity groups mainly consisted of collections from middle-northern area and southern area, respectively, while the medium group consisted of accessions from all over the country. Average 1,000-seed weight (TSW) was 2.7 g. TSW of the collection from Hamyang was the greatest a 3.9 g, while the TSW of Pyungchang collection was the smallest as 1.7 g, and most of collections produced medium and small seeds. Perilla accessions with greate 1,000-seed weight seemed to be belonged to the late maturity group. Seed coat colors of perilla accessions were dark brown (30％), brown (55％) and gray brown (6％), respectively, Among seed coat colors, brown color consisted of 91％. Stem height, the number of nodes, branches, flower clusters, and capsules per flower cluster, and the length of flower cluster were positively correlated occ, while these characteristics were negatively correlated with the number of capsules per flower cluster and 1,000-seed weight. These results allowed us to select 5 perilla collections, containing 1 collection with gray white seed color, and 4 collections over 2.5g 1000 seed weight, as parental lines in the breeding program.

• Research in Plant Disease
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• v.9 no.2
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• pp.68-71
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• 2003

Correlation between rice yield loss and infection time of neck blast after panicle emergence was analyzed in paddy fields at Icheon in 1999 and 2000. As the neck blast occurred at early heading stage, the yield loss of a early maturity variety, Jinmibyeo, ranged from 83.9% to 81.6%, while it ranged from 44.3% to 33.1% when the disease developed 30 days after heading. The regression equations of yield loss(y) caused by the neck blast infection time(x) in Jinmibyeo were y =1.2717x + 79.523(R2 = 0.9487) and y = 1.6872x + 74.545(R2 = 0.7993) in 1999 and 2000. In a mid-lately maturity variety, Chucheongbyeo, yield loss ranged from 64.9% to 47.8% when the disease developed at early heading stage. While it ranged from 29.1% to 8.9% when the disease occurred 40 days after heading. The regression equations of yield loss caused by the disease in Chucheongbyeo were y= 1.2717x + 79.523($R^2$ = 0.9487) and y = 1.6872x + 74.545(($R^2$ = 0.7993) in 1999 and 2000. Weights of 1,000 rice grains of Jinmibyeo and Chucheongbyeo were also drastically decreased to 38.3% and 57.3%, respectively, compared to healthy control when the disease occurred at early heading stage. However, weights of the two cultivars were 87.6% and 92.9% compared to control when the disease developed after 40 days of heading. Results indicated that there is a highly negative correlation between rice yield loss and infection time of the neck blast.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.3
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• pp.195-200
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• 1990

These experiments were conducted to determine the effect of high temperature and water managements on growth and yield of rice. Shoot dry weight and percent of fresh roots were decreased when rice plant was exposed to high temperature, and also high temperature treatment decreased yield components of rice through spikelet number at meiotic, filled grain ratio and percent of fertility at heading, and 1,000 grain weight at ripening stage. Nitragen content of the rice varities was decreased by high temperature treatment regardless different growth stage, although Si content increased. Grain yield of rice varieties significantly decreased due to high temperature when rice plants were treated at heading stage followed by ripening stage. meiotic, young panicle initiation, maximum tillering and tillering stage in order. Effect of the continual submerging on temperature increased by 1.1$^{\circ}C$ at daytime and by 3.7$^{\circ}C$ at nighttime, but flowing water irrigation which can maintain optimum temperature reduced plant height and increased dry weight and percent of fresh roots. Flowing water irrigation showed higher yield by 4-8% compared to continual submerging method through increment of yield components such as spikelet number, filled grain ratio and 1,000-grain weight.

• Korean Journal of Organic Agriculture
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• v.11 no.3
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• pp.75-90
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• 2003

A total of 192 Korean landraces were investigated for the comparison of each other as useful germplasm to organic farming and examined correlation between quantitative traits. Almost Korean landraces were classified into medium-heading variety and average days from seeding to heading was 111.1 days. Plant height and culm length were longer about 20∼40cm than general Japonica cultivar. Average width of leaf blade and average length of panicle were 1.3cm and 22.4cm, respectively, Average number of panicles per plant was 10.0 and almost varieties showed low tilling habit. Average length/width ratio of brown rice was 1.7 and several varieties were long grain type and average 1,000 grain weight was 21.6g. In correlation coefficient among quantitative traits, positive significant correlations were observed between culm length and leaf width, days from seeding to heading, but negative correlations were observed between days from seeding to heading and 1000 grain weight. 27.1% of Korean landraces showed weak and lodging degree in culm strength and 3.6% of total varieties showed purple margin on leaf blade and leaf sheath. In leaf blade angle and flag leaf angle, erect type was 46.9% and 10.9%, respectively. 24.0% of total varieties showed the slow and late degree of leaf senescence. The rate of awned type, waxy type and brown seed coat were 74.5%, 20.3% and 4.2%, respectively. The color of stigma, spikelet, apiculus and awn showed diverse color such as white, brown, red and purple.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.521-531
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• 1991

Greenhouse experiments were conducted at the International Rice Research Institute during the 1989 dry season to investigate varietal differences in morpho-anatomical characters affecting spikelet filling in different tiller orders. There were varietal differences in tiller initiation and heading dates, and tiller duration. The main culm bad competitive advantage over the other tillers. The maximum contribution to filled spikelet weight was made by primary tillers in low tillering cultivars and by secondary tillers in high tillering cultivars. The reduction in inner vascular bundle (IVB) by tiller orders and the namber of IVB and outer vascular bundles (OVB) varied amop.g cultivars. The number of IVB in the peduncle of IR30, Rewa and Hybrid was more than OVB but in IR47705, Silewah, Unbongbyeo and SR14453, OVB was more than IVB. Early formed tillers produced more IVB than the late formed tillers. The number of IVB was positively correlated with number of spikelet and filled spikelet weight, however percent of filled spikelet did not show significant differences as well as 1000 spikelet weight in all types of cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.215-218
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• 2012

We have carried out the experiment to investigate optimal drainage time of barley seeding synchronized with rice harvesting in paddy field. Number of emerged barley seedling on moist paddy field was less than that of common paddy field. It is very hard to plow using combine owing to long time to work on wet condition compared to drying condition of paddy field. According to the drainage time, growth and yield of barley were not significantly different. However, late drainage time decreased the spikes per $m^2$. Rice yield and 1,000 husked rice grain weight were not significant depending on drainage times at 15 days, 20 days and 25 days before barley seeding. The range of 1,000 husked rice grain weight was 21.7~22.2 g on different drainage conditions. In results, on considering of soil hardness and time of labor, the optimal contents of soil moisture was about 33%. This study reveals that drainage time at 20 days before barley seeding is proper to increase seedlings and yield.

• Proceedings of the Korean Society of Organic Agriculture Conference
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• 2009.12a
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• pp.282-282
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• 2009

환경오염에 대한 우려 및 안전농산물에 대한 소비자욕구 증대로 유기농산물 시장규모가 최근 3년간 2.8배 성장 추세이다. 친환경농산물 인증면적은 '00년 2,039 ha에서 '07년 122,882 ha로 급격히 증가하고 있으나 생태적 원리에 부합된 벼 재배기술이 부족하며 특히 무경운 논토양에 대한 경영분석 자료는 거의 없는 실정이다. 본 연구는 유기농업기술을 종합적으로 투입한 시범마을을 육성하기 위하여 하동군 양보면 예성마을 1ha를 대상으로 관행농업과 무경운 자운영 피복 벼 기계이앙을 실증하여 경제적인 효과를 검토하였다. 토양 관리를 위해 2007년 9월 10일에 자운영을 3 kg/10a 파종하여 겨울철 토양 생태계를 유지하였고 화학비료나 농약을 사용하지 않았다. 볍씨 소독은 마른 종자를 60 $^{\circ}C$에서 8분간 침지하는 열탕침법을 이용하였으며 논 물담기는 5월 28일경 15 cm 이상 깊게 하여 자운영이 잘 분해되도록 하였다. 기계이앙은 6월 10일경 표면 1 cm 이내의 물 깊이에서 식부장치를 최대한 깊게하고 주수는 주당 5-7주 정도로 실시하였으며 기계이앙 후에는 5일 정도 물을 담지 않고 그대로 두고 그 후 물을 10 cm 이상 깊게 하여 잡초발생을 억제하였다. 중간낙수는 7월 10일경 1회 처리하였고 수확기 낙수는 9월 23일 실시하였다. 무경운 처리구의 이앙전 토양 가밀도는 관행 1.30 g $cm^{-3}$ 비해 0.09 g $cm^{-3}$ 정도 가벼운 것으로 나타났고 공극률은 관행 50.8%에 비해 3.5% 높은 것으로 나타났으며 특히 수분률이 3.5% 높았다. 무경운 자운영 피복 기계이앙 처리구의 잡초발생 건물량은 7월 4일경 피 8.8 g $m^{-2}$, 여뀌 10.8 g $m^{-2}$ 이었으며 9월 18일에는 피 16.0 g $m^{-2}$, 여뀌 12.3 g $m^{-2}$였다. 수확기 관행처리구의 주당 이삭수는 16.7개, 수당립수는 101개, 천립중은 25.4 g, 등숙비율은 82.3%로 수량은 517 kg $10a^{-1}$ 였으며 무경운 자운영 피복 기계이앙은 주당 이삭수가 14.1개, 수당 립수는 103개, 천립중은 26.2 g, 등숙비율은 91.2%로 수량이 456 kg $10a^{-1}$였다. 무경운 자운영피복 벼 기계이앙은 기경작업이나 시비작업 등이 없으므로 노동력이 60% 절감되었으며 농가소득은 5% 증대되었다. 따라서 농업분야 저탄소 녹색성장과 관련하여 자연 생태계를 보전하면서 농가소득을 유지할 수 있는 방법으로 무경운 자운영 피복 벼 기계이앙이 효과적인 것으로 판단되었다.