• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.1
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• pp.22-29
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• 2020

Rice is very sensitive to high temperatures during the reproductive stage, particularly during the flowering and anthesis periods. To determine how high temperatures result in sterility during the flowering period in Korean rice cultivars, groups of 11 cultivars were subjected to different temperature regimes (24, 28, 30, and 33℃) during the flowering stage using sunlit phytotrons. At an average of 33℃, all 11 rice cultivars reached anthesis earlier than at the other temperatures. Microscopy analyses revealed significant differences in pollen germination and pollen viability in cultivars grown at 33℃ compared to those cultured at lower temperatures. At 33℃, the cultivars had significantly lower fertility rates (47% reduction) than cultivars grown at 24℃. These findings are important as rice pollination and fertility depend on the pollen viability and germination. The present study shows that rice fertility is negatively affected by excessively high temperatures.

• Journal of The Korean Society of Grassland and Forage Science
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• v.18 no.1
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• pp.11-18
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• 1998

Twelve Italian ryegrass (Lolium mult~flomm L.) cultivars have recommended as the government recommended forage cultivars since 1984, however, the forage performance and quality have been mostly tested at two locations, such as Suweon and Sunghwan in the Middle Northwestern and Middle Southwestern Coast Regions, respectively. Therefore, the objective of this experiment was to retest the forage performance and quality of already recommended twelve government Italian ryegrass cultivars at five scattered locations, such as Icheon, Suweon, Sunghwan, Keon- and Kwangju from 1992 to 1995 with the intention of improving recommendations to dairy farmers. Cultivars with more dry matter yield than the control 'Tetrone' were 'Tosca' , 'Bartissimo' , 'Florida 80' and 'Gordo' in the Middle Northwestern Coast Region ; 'Tosca' , 'Florida 80' , 'Bartissimo' , 'Wencke' and 'Gordo' in the Middle Southwestern Coast Region ; 'Tosca' , 'Florida 80' , 'Sikem' , 'Bartissimo' , 'Wencke' and 'Gordo' in the Keongbuk Inland Region; 'Florida 80', 'Tosca' , 'Barmultra' and 'Bartissimo' in the Southern Inland Region and 'Florida 80' , 'Gordo' , 'Sikem' , 'Bartissimo' and 'Tosca' in the Southern Coast Region. At all the locations in 1992-95, 'Florida 80' produced the highest forage yield and showed earliness, but this cultivar was less cold tolerant in the Middle Northwestern and Middle Southwestern Coast Regions and grew tall which made it vulnerable to lodging in all the exprimental regions except the Southern Coast. Differences among the ryegrass cultivars for the three year mean ADF and NDF were small and inconsistent.

• Horticultural Science & Technology
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• v.30 no.4
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• pp.363-370
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• 2012

Some physicochemical characteristics like nutritional values, sugar content, and fatty acid composition (FAs) in fruits of four papaya (Carica papaya L.) cultivars ('Red Lady', 'Sunrise Solo', 'Tainung', and 'BH-65') grown under plastic greenhouse conditions in the Mediterranean region of Turkey were evaluated. The chemical characteristics, except acidity in the fruits, significantly varied among the cultivars. Nitrogen (N) was the most abundant mineral in all papaya cultivars and ranged from $0.80\;g{\cdot}100\;g^{-1}$ in 'Red Lady' to $1.28\;g{\cdot}100\;g^{-1}$ in 'BH-65' in fresh weight. Potassium (K) and calcium (Ca) were found the highest amount in dry weight. Glucose and fructose were identified as the main sugars in all cultivars. Sucrose was in trace amounts in the three cultivars, but not detectable in cultivar 'Red Lady'. Twenty-five FAs were detected in the papaya fruits. Polyunsaturated fatty acids (PUFAs) were found to be in a highest amounts compared to the saturated fatty acid (SFAs) and monounsaturated fatty acids (MUFAs). Palmitic (C16:0), oleic (C18:1), and linoleic (C18:2n6) acids were the major fatty acids detected in all cultivars. The results of this study implied that dietary intake of papayas may supply substantial nutrient components necessary for human health.

• Korean Journal of Plant Resources
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• v.24 no.6
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• pp.675-687
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• 2011

Mulberries have importance in the sericulture industry as food for Bombyx mori, silkworm reared for its silk. Korean Morus alba have many cultivars and, for the protection of these cultivars and for utilization in plant-breeding programs, genetic information and the diversity among cultivars are essential. This study with 14 mulberry genotypes was undertaken using RAPD and ISSR fingerprinting to discover the genetic divergences between cultivars. Polymorphism rate among the cultivars produced by RAPD primer was found to be 64.48% and 66.29% relative to ISSR primer. The genetic relationships among the cultivars were identified using a dendrogram constructed with the UPGMA clustering method. Nei's method was used to calculate the genetic dissimilarity coefficients between each pair of genotypes, and the highest dissimilarity coefficient of 0.246 was exhibited between Suwon and Hwanggum cultivars. To determine the efficiency of each primer, a polymorphic index was calculated, and the robustness of the dendrogram was checked using cophenetic correlation coefficient. The results of this study can be utilized for the improvement of mulberry varieties in plant-breeding programs.

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.3
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• pp.231-238
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• 1997

Six rape (Brassica napus subsp. oleifera) cultivars have been recommended as the government recommended forage cultivars since 1984, however, the forage performance and quality have been mostly tested at two locations, such as Suweon in the Middle Northwestern Coast Region and Sunghwan in the Middle Southwestern Coast Region. Therefore, the objective of this experiment was to retest the forage performance and quality of already recommended four government rape cultivars at five scattered locations, such as Icheon, Suweon, Sunghwan, Keongsan and Kwangju fiom 1992 to 1994 with the intention of improving recommendations to dairy farmers. Among the rape cultivars tested, 'Bamapoli' and 'Sparta' (including 'Ramon' at Kwangju) gave the highest yields at all locations in 1992-94, whereas 'Akela' had the lowest yield. Mean plant heights varied fiom 50 to 69cm and 'Bamapoli' was the tallest rape, followed by 'Sparta', 'Ramon' and 'Akela' at all locations. Mean ADF contents for rape cultivars ranged fiom 16.7% for 'Akela' to 19.3% for 'Bamapoli', while mean NDF contents ranged fiom 22.3% for 'Akela' to 24.9% for 'Bamapoli'. The government recommended rape cultivars tested were generally well adapted across the country, however, in forage production situations in the fall where high yield is more important, 'Bamapoli', 'Sparta' and 'Ramon' might be preferable.

• Korean Journal of Breeding Science
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• v.43 no.4
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• pp.273-281
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• 2011

Fusarium head blight (FHB), also known as scab, caused mainly by Fusarium graminearum is a devastating disease of wheat in regions that are warm and humid during flowering. In addition to significant yield and quality losses, the mycotoxin deoxynivalenol produced by the pathogen in infected wheat kernels is a serious problem for food and feed safety. Twenty- three Korean cultivars and "Sumai 3", which is a FHB-resistant Chinese cultivar were tested for Type I, Type II resistances of FHB. Three cultivars were identified as resistant in Type I assessment, and two cultivars were resistant in Type II assessment. Genetic variation and relationship among the cultivars were evaluated on the basis of 11 Simple Sequence Repeat (SSR) and 29 Sequence Tagged Site (STS) markers that were linked to FHB resistance Quantitative Trait Loci (QTL) on chromosome 3BS. One SSR and 7 STS markers detected polymorphisms. Especially, using a STS marker (XSTS3B-57), 32.4% of the variation for Type II FHB resistance could be explained. Genetic relationship among Korean wheat cultivars was generally consistent with their released year. These markers on chromosome 3BS have the potential for accelerating the development of Korean wheat cultivars with improved Fusarium head blight resistance through the use of marker-assisted selection.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.339-346
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• 2021

Prevalence of tan spot of wheat caused by the fungus Pyrenophora tritici-repentis has become more prevalent in Oklahoma as no-till cultivation in wheat has increased. Hence, developing wheat varieties resistant to tan spot has been emphasized, and selecting pathogen isolates to screen for resistance to this disease is critical. Twelve isolates of P. tritici-repentis were used to inoculate 11 wheat cultivars in a greenhouse study in splitplot experiments. Virulence of isolates and cultivar resistance were measured in percent leaf area infection for all possible isolate x cultivar interactions. Isolates differed significantly (P < 0.01) in virulence on wheat cultivars, and cultivars differed significantly in disease reaction to isolates. Increased virulence of isolates detected increased variability in cultivar response (percent leaf area infection) (r = 0.56, P < 0.05) while increased susceptibility in cultivars detected increased variance in virulence of the isolates (r = 0.76, P < 0.01). A significant isolate × cultivar interaction indicated specificity between isolates and cultivars, however, cluster analysis indicated low to moderate physiological specialization. Similarity in wheat cultivars in response to pathogen isolates also was determined by cluster analysis. The use of diverse isolates of the fungus would facilitate evaluation of resistance in wheat cultivars to tan spot.

• Journal of Environmental Science International
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• v.31 no.5
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• pp.413-422
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• 2022

To identify rice (Oryza sativa L.) cultivars suitable for Italian ryegrass (Lolium multiflorum Lam.)-rice double cropping systems, we investigated the yield and grain quality of four different midseason maturing rice cultivars ('Daebo', 'Haepum', 'Haiami', and 'Samdeog') and four midseason-to-late maturing rice cultivars ('Hyunpoom', 'Saeilmi', 'Saenuri', and 'Samkwang') in single rice cropping and Italian ryegrass-rice double cropping systems in paddy fields of Miryang, South Korea. We found that organic matter and available P₂O₅ content slightly decreased, whereas Na content increased, in the soil where Italian ryegrass was cultivated during winter compared to that in the soil that remained fallow during winter. The pH, electrical conductivity, organic matter, and contents of K⁺, Ca²⁺, Mg²⁺, and Na⁺ decreased, whereas the available P₂O₅ content slightly increased, in the soil where rice was harvested in both single and double cropping systems. However, compared to the optimum soil conditions for rice cultivation, available P₂O₅ and K⁺ content were high and Mg²⁺ content was low in both single and double cropping systems. At the heading stage, the culm length and leaf color slightly increased in most of the rice cultivars, whereas the panicle length and number slightly decreased, in the double cropped system. After harvesting, spikelet number and milled rice yield did not show a significant difference between single and double cropping systems. However, the ripened grain rate and weight per thousand grains increased slightly in the 'Saeilmi' and 'Samkwang' cultivars but remained either stable or slightly low in other cultivars in the double cropping system. The milled rice yield was high (> 500 kg/10a) in 'Daebo' and 'Haepum' among midseason maturing rice cultivars, and in 'Saeilmi' and 'Saenuri' among midseason-to-late maturing rice cultivars, in both single and double cropping systems. The head rice rate was high in midseason maturing rice cultivars in the double cropping systems, reaching > 70% in 'Haepum' and 'Haiami' cultivars, whereas it decreased in most midseason-to-late maturing rice cultivars (excluding 'Samkwang' cultivar), in double cropping systems. Particularly, it exceeded > 70% in the 'Saenuri' cultivar in both single and double cropping systems. The protein content in milled rice increased, whereas the amylose content either remained stable or slightly increased, in double cropping systems. The Toyo taste value decreased in all midseason-to-late maturing rice cultivars and slightly increased in the 'Daebo' and 'Haiami' cultivars among midseason maturing rice cultivars in double cropping systems. However, Toyo taste values in the 'Haepum', 'Haiami', and 'Saenuri' cultivars exceeding > 80% in both single and double cropping systems. Therefore, we recommend 'Haepum', 'Haiami', and 'Saenuri' cultivars as candidates for Italian ryegrass-rice double cropping systems due to high yield, head rice rate, and Toyo taste value.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.135-140
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• 2008

Improving eating quality is one of the most important objectives in japonica rice breeding programs in Yunnan Province of China. Eating quality and its relevant traits of nine Korean and 11 Yunnan rice cultivars were comparatively analyzed in this study. The grain shape of most Yunnan japonica rice cultivars have a relatively slender shape and are slightly larger than Korean rice cultivars. Palatability value of cooked rice of Yunnan rice cultivars was significantly lower, while the protein content of Yunnan rice cultivars was significantly higher than that of Korean cultivars. Peak viscosity and breakdown viscosity of the Yunnan rice cultivars were significantly lower, while setback viscosity of the Yunnan rice cultivars was significantly higher than in Korean rice cultivars. Palatability value of cooked rice was negatively correlated with protein content and setback viscosity but positively correlated with peak viscosity, breakdown viscosity, and cool paste viscosity. Through multiple linear regression analysis, an equation for estimating palatability value(PV) of cooked rice based on quality traits was generated as dependent only upon protein content(PC), PV=139.024-(10.865$\times$PC) with an $R^2$ value of 0.822. The results suggest that reducing protein contents should be the major target in improving eating quality of Yunnan japonica rice cultivars through integrated approaches of both cultivar development and appropriate cultural practices. Genetic similarities among cultivars based on DNA markers which had been identified as associated with grain quality seemed not to be directly related to PV.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.4
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• pp.30-36
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• 2014

This study was conducted to determine the causes of unreasonable prices and small numbers of azalea cultivars by analyzing the price trends and the number of azalea cultivars announced over the last 25 years based on data from the Public Procurement Service(PPS), Korea Price Research Center and the Landscaping Tree Association(LTA)(hereinafter, officially announcing agencies and organizations) which are major references used when landscape planting is decided. The prices of azalea cultivars announced by the official announcing agencies and organizations have moved in similar patterns over the past 25 years because the prices of azalea cultivars announced by the LTA were referred to by other official announcing agencies and organizations when they officially announced the prices of azalea cultivars. The PPS set lower officially fixed prices of azalea cultivars compared to other official announcing agencies and organizations, and the reason for this is considered to be the intention of the PPS to suppress landscape tree price increases because of the government's policies to suppress price increases. The prices of azalea cultivars seem to change rapidly due to the imbalance between the demand and supply of azalea cultivars rather than the effects of consumer price fluctuation rates because the production periods of azalea cultivars are shorter when compared to other landscape trees. The prices of azalea cultivars from the official announcing agencies and organizations have been set higher than the prices in actual transactions. The reason for this is considered to be the intention of the official announcing agencies and organizations to allow landscaping companies to cover defect costs resulting from the practice of subcontracting planting work and secure profits of subcontractors for planting work. The official announcing agencies and organizations have simply announced prices of 5~8 main azalea cultivars that have been used in the past. The names of azalea cultivars being cultivated and criteria for classification have not been clear; thus, landscape designers have not written clear names of azalea cultivars to be cultivated on planting drawings as practice and landscapers planted those azalea cultivars which could be easily obtained. Therefore, it is assumed that there has been no demand for new azalea cultivars. Thus, the vicious circle in which the prices of only those azalea cultivars that were produced in the past have been announced is repeated.