• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.343-349
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• 1993

This study was conducted 1)to determine the factors responsible for the gradually increased rice yield by examining any improvements in yield-related characters and physiological characters among the historically recommended varieties of rice in Korea, and 2)to reveal the way of achieving further yield improvement by breeding in the future. Eight recommended varieties from 1911 to 1988 were selected and grown at the same conditions. The yield-related characters were observed at the harvest time, and the physiological characters such as RGR, NAR, LAR, SLA and L WR were estimated by the classical method of growth analysis. The newer varieties are shorter and those released after 1970's are greater in percent of filled spikelets and harvest index than the older varieties. There are no definite changing trends in the variations of number of panicles per hill, number of spikelets per panicle and 1000 grain weight according to the course of evolution in the recommended varieties. There is little evidence of improvement in the physiological characters such as NAR, LAR, SLA and LWR among the recently developed varieties compared with those of the older varieties. The increase in grain yield due to variety improvement, if any, is largely associated with the greater harvest index and percent of filled spikelets by breeding blight resistant and / or lodging resistant genotypes with short culm. It is suggested that increase in NAR should be carried out simultaneously with increase in harvest index to breed high yielding genotypes. I t appears to be important to breed genotypes with long culm in order to enhance light penetration into the canopy as long as they are lodging resistant. Since NAR is negatively correlated with LAR, it is unlikely to succeed to improve both characters simultaneously. The direct effect of NAR on RGR by path analysis is much larger than that of LAR, and hence it is suggested that breeding genotype with large NAR is more effective on enhancing RGR. It is also suggested that improving LAR through LWR is likely effective on increasing RGR.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.6
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• pp.361-365
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• 2000

This study was carried out to evaluate yearly variation and stability of yield and yield components of fifteen rice varieties. Yield stability and universal variety parameter of rice varieties were utilized for statistical model developed by Stroike, Grafius, and Finlay respectively. The lowest yearly variation based on coefficient of variation was found in Dasanbyeo for number of panicles/hill, in Jodongji for number of grains/panicle, in Yongmoonbyeo for ripened grain ratio, in Nagdongbyeo for 1,000 grain weight, and in Dasanbyeo for grain yield. Stability analysis by Stroike and Johnson's model revealed that Ilpumbyeo, Hwaseongbyeo, Dongjinbyeo in Japonica type, and And-abyeo and Dasanbyeo in Tongil type had the higher stability above average. Universal varieties analyzed by Grafius model were Ilpumbyeo, Dongjinbyeo, Hwaseongbyeo, Nagdongbyeo, and Jodongji in Japonica, and Dasanbyeo and Samgangbyeo in Tongil type. Damageum, Dongjinbyeo, Hwaseongbyeo and Ilpumbyeo in Japonica, and Dasanbyeo and Yongmoonbyeo in Tongil type were found to be highly stable as analyzed by Finlay ＆ Wilkinson's model. In conclusion, with reference to both grain yield and stability based on above three methods, Ilpumbyeo, Hwaseongbyeo, and Dongjinbyeo in Japonica, and Dasanbyeo in Tongil type were evaluated to be highly year-stable and high-yielding.

• Molecules and Cells
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• v.24 no.1
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• pp.83-94
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• 2007

During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with $F_2$ and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.

• Korean Journal of Soil Science and Fertilizer
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• v.7 no.2
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• pp.107-112
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• 1974

In order to establish a rational application method of potash to paddy rice(Oryza sativa L. Jinheung, a Japonica variety) field and pot experiments on split application of two rates (6kg and 12kg $K_2O$ per 10a) of potash at a certain critical growing stage have conducted in 1973 and the results were as follows: 1. At the treatment where a rate of 6kg $K_2O$ per 10a(lower dose) of potash was supplied in two split doses, a half at transplanting time and the other half at young panicle formation stage, the yield of paddy rice appeatred to be low due to less number of panicles per hill. (Field experiment) 2. The treatment where potash supply ceased at transplanting time or at effective tillering stage but supplied at the other two stages (including panicle initiation stage) have failed to increase K content in the flag leaf and have shown low maturity and low thousand grain weight, which resulted in low paddy rice yield. (pot experiment) 3. From above two facts, it is concluded that the application of potash at transplanting time is an important practice for the high yielding of paddy rice. 4. The application of lime seemed to stimulate later growth of paddy depressing the unnecessary increase of poor miserable tillers in early stages of growth.

• Korean Journal of Breeding Science
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• v.40 no.2
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• pp.143-152
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• 2008

This study was conducted to obtain basic information on mainstem, branch and leaf characteristics related to canopy for development of high yielding cultivar using 70 Korean soybean cultivars developed from 1913 to 2000. Variations of canopy width, branch length, and canopy width/length ratio were higher compared to other characteristics among 12 mainstem and branch characters. Variations of petiole angle, leaflet width/length ratio and compound leaf dry weight were higher than other characteristics among eight leaf characters related to plant canopy. Three classifications of soybean cultivars were used based on usage: I)soy sauce and tofu, II)bean sprout, and III)cooking with rice. Canopy width/length ratio was higher in group III, cooking with rice than group I, soy sauce and tofu, and group II, bean sprout, and there was no difference between the two, group I and group II. The total branch length/main stem height ratio was higher in group II, bean sprout and group III, cooking with rice than group I, soy sauce and tofu. Mainstem and branch characteristics related to plant canopy were classified into four groups by ratio of canopy width/length and total branch length/main stem length, respectively. Soybean cultivars with narrow canopy and high dependence of mainstem were Danweonkong, Keumkangkong, Shelby, and Shinpaldalkong. Soybean cultivars with broad canopy and high dependence of mainstem were Kanglim, Keumkangdaelip, and Jinyulkong, and a cultivar with broad canopy and high dependence of branch were Geomjeongkong 2. Leaflet length/width ratio was lowest in cooking with rice and there was no difference between soy sauce and tofu and bean sprout. Compound leaf area was largest in cooking with rice and smallest in bean sprout. Leaf petiole length was short in bean sprout and there was no difference between soy sauce and tofu and bean sprout. Leaf petiole angle was highest in cooking with rice and lowest in bean sprout. Leaf type was classified into four groups based on leaflet width/length ratio and compound leaf area, respectivly. Buseok and Taekwangkong had an oval leaflet and largest area of compound leaf. Eunhakong and Sohokong had extreme narrow leaflet and smallest area of compound leaf. Leaf petiole type was classified into three and four groups based on leaf petiole length and angle, respectively. A soybean cultivar with the shortest petiole length and smallest petiole angle was Eunhakong and cultivars with short petiole length and large petiole angle were Alchankong, Muhankong, and Pureunkong. A soybean cultivar with long petiole length and small petiole angle was Sinpaldalkong 2. Among a total of 70 Korean soybean cultivars, Eunhakong had an extreme narrow type in leaf, smallest compound leaf area, shortest petiole length, and smallest petiole angle of compound leaf.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.3
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• pp.183-199
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• 1976

1. The cultivated land in Korea has originally low fertility resulting in high dependence to fertilizers. 2. The total fertilizer requirement calculated by the Office of Rural Development (ORD) in 1976 was about 1,153 thousand mts, and the total amount of supply planned by the Ministry of Agriculture and Fishery was 1,010 thoushand mts which is close to the amount calculated by ORD. However, there is some gap between the amount of recommended (N, 11.6; $P_2O_5$: $K_2O$, 7.3kg/10a> and supply planned (N, 12.0; $P_2O_5$, 6.3; $K_2O$. 4.8kg/10a) fertilizers for each elements per unit area 3. For 15 years from 1960 to 1975 the fertilizer consumption of nitrogen was roughly increased from 200,000 mts to 500,000 mts; phosphorus, from 50,000 to 250,000 mts; potassium, from 10, 000 to 170,000 mts; accounting 2.5, 5, and 17 times of increase respectively. 4. The total fertilizer consumption for 5 years from 1967 to 1971 was about 100,000 mts and another 5years from 1971 to 1975 was 300,000 mts indicating three times increase. 5. The direct factors influenced to the increase of fertilizer consumption in recent years are 1) the dissemination of high yielding Tongil type rice varieties which are resistant to heavy fertilization 2) high price policy for agricaltural products 3) increased cultivation of vegetables:, fruits, and forages which require high level of fertilizers. The indirect factors are 1) dissemination of new improved agricultural techniques, 2, improvement of cultivated land conditions through irrigation system and land reform, 3) increased supply of silicate fertilizers, and 4) increase of farm income. 6. The percentage of total fertilizer consumption by rice (32%) and barley (25%) is about 57%. The ratio of total fertilizer consumption by vegetables and forages is expected to increase greatly. 7. Based on the increasing tendency of cultivated land and yield per unit area for last 10 years in each crop, total fertilizer consumptions in 1980, 1990, and 2000 year are estimated to 1,290,000, 1,580,000 and 1,870,000 mts respectively.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.640-644
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• 2009

A new sprout-soybean cultivar, "Sohwang" was developed at the National Institute of Crop Science (NICS) in 2008. "Sohwang" was selected from a cross between Pungsan and Pungsan/Nattosan. The preliminary, advanced, and regional yield trials to evaluate the performance of Iksan 58 were carried out from 2004 to 2008. This cultivar has a determinate growth habit with purple flower, grayish brown pubescence, yellow seed coat, Yellow hilum, lanceolate leaflet shape and small seed size (8.5 grams per 100 seeds). The maturity date of "Sohwang" is 10 days earlier than the check variety, "Pungsan". It has a good seed quality for soybean-sprout. The soybean-sprouts grown from "Sohwang" have high isoflavone ($3,041{\mu}g/g$)contents. This cultivar has resistance to soybean mosaic virus (SMV) and necrotic symptom (SMV-N), and other most troublesome soybean diseases which are bacterial pustule and black root rot. Especially, "Sohwang" has useful characteristics, such as lodging and shattering resistance. The average yield of "Sohwang" was 2.69 ton per hectare in the carried out for three years from 2006 to 2008 regional yield trials(RYT) for double cropping.

• Korean Journal of Breeding Science
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• v.41 no.1
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• pp.56-60
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• 2009

A new naked oat cultivar Daeyang (Avena sativa L.) was developed by Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. It was derived from a cross between 'FLX446-1-84-Q1'. and 'SO92004-B-3-3-5-7'. The FLX446-1-84-Q1, a naked oat cultivar from USA, is early heading and has good seed quality, while the SO92004-B-3-3-5-7, a covered oat breeding line, has a high yield with large grain. Subsequent generations were handled in a bulk method and pedigree selection program, and the SO97013-B-16-4 was selected based on agronomic performance in 2001. The line showed both high yield and good husking rate of seed in the yield trial tested at Suwon from 2002 to 2003, being designated as Gwiri51. The Gwiri51 was subsequently evaluated for winter hardiness, earliness, and yield in four locations, Gimje, Iksan, Jeongeup, and Jinju, from 2004 to 2007 and was designated as "Daeyang" and released. Its heading date was May 8 and maturing time was June 14 in a paddy field condition. The new cultivar Daeyang had 97 cm of culm length and 25.2 cm of spike length, 644 spikes per $m^2$, 65 grains per spike, 30.3 g of 1,000-grain weight, and 635 g of test weight. Daeyang showed better winter hardiness than that of the check cultivar 'Sunyang', and similar seed quality to the check cultivar in respect to percent content crude protein and $\beta$-glucan. However, it showed higher husking rate than the check cultivar. Grain yield of Daeyang in the regional yield trial for 4 years were averaged 4.18 MT $ha^{-1}$, which was 20% higher than that of the check cultivar Sunyang. Fall sowing cropping is recommended only in a south area where daily minimum mean temperatures are averaged higher than $-4^{\circ}C$ in January, and should be excluded in mountain area where frost damage is presumable.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.187-196
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• 2009

The objectives of this study were to evaluate the different cutting dates on the changes of feed quality among five cereals (barley, wheat, rye, triticale and oat) for whole crop silage. Field trials were conducted at paddy field in Yesan, Chungnam Province and the aerial parts were clipped 10 days from 15 March to 15 June. Changes of acid detergent fiber (ADF) content in relation to different cutting dates was described by a quadratic curve for 5 winter cereals crops. ADF content reached a maximum at 5 days after heading in barley cultivar 'Youngyang', 7 days in wheat 'Keumkang', 18 days in rye 'Gogu', 1 days in triticale 'Shinyoung' and 10 days in oat 'Samhan'. Neutral detergent fiber (NDF) content were linearly increased as growing after overwintering and stagnated or slightly decreased after heading. The crude protein were linearly decreased throughout the growth period of 5 whole crop cereals. Digestible dry matter (DDM) content were decreased from early stages to heading and subsequently increased as grain filling. Relative feed value (RFV) for 5 crops were decreased as growing and subsequently increased as grain filling after heading. Barley cultivar for only forage use 'Youngyang' were lower at ADF and NDF content and higher at DDM and RFV after heading than those of other cereals for forage use. So, barley for whole crop silage was a good crop with high feed quality and high proportion of spikes compared with other winter cereal crops. Wheat cultivar for grain 'Keumkang' were higher at crude protein than those of other four cereals from overwintering to maturing and were higher at DDM and RFV after heading than those of rye, triticale and oat. Rye cultivar with cold tolerant and high fresh yielding 'Gogu' were highest at ADF and NDF content and lowest at DDM content and RFV. So, rye was a crop with low quality for forage use compared to other winter cereal crops. Triticale cultivar with flourishing and high yielding 'Shinyoung' was intermediated between barley and rye, and were linearly increased at DDM yield by different cutting dates. Oat cultivar with cold tolerant and high tillering 'Samhan' were lower at ADF and NDF content and higher at crude protein before heading, but after heading, there are not especially advantages compared to barley, wheat or triticale.

• KSBB Journal
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• v.22 no.5
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• pp.305-312
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• 2007

It is crucial to develop a miniaturized cultivation method for large and rapid screening of high-yielding mutants of monacolin-K, a powerful anti-hypercholesterolemic secondary metabolite biosynthesized by the fungal cells of Monascus ruber. In order to investigate as many strains as possible in a short time, a miniaturized fermentation method especially suitable for the cultivation of the filamentous Monascus mutants was developed using $50m{\ell}$ culture-tube ($7m{\ell}$ of working volume) instead of the traditional $250m{\ell}$ flask ($50m{\ell}$ of working volume). Generally, in filamentous fungal cell fermentations, morphologies in growth and production cultures should be maintained as thick filamentous and compact-pelleted (usually less than 1 mm in diameter) forms, respectively, for enhanced production of secondary metabolites in final production cultures. In this study, we intended to induce the respective optimal morphologies in the miniaturized culture system for the purpose of rapid screening of overproducers. Miniaturized growth culture system was successfully developed due to the mass production of spores in the statistically optimized solid medium. When large amounts of spores were inoculated into the growth cultures, and brown rice flour (20 g/L) was also supplemented to the growth medium, dense filamentous morphologies were successfully induced in the growth cultures performed with the 50 ml culture tubes. It was implied that the amounts of spores inoculated into the growth tube-cultures and the growth medium components should be the key factors for the induction of the filamentous forms in the growth fermentations. Furthermore, in order to statistically optimize production medium, multiple experiments based on Plackett-Burman design and response surface method (RSM) were carried out, resulting in more than 2 fold enhanced production of monacolin-K in the final production cultures with the optimized production medium. Notably, under the production culture conditions with the statistically optimized medium, optimal pellet sizes below 1 mm in diameter were reproducibly induced, in contrast to the thick and viscous filamentous morphologies observed in the previous production cultures.