• Asian Journal of Turfgrass Science
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• v.25 no.2
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• pp.133-137
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• 2011

Winterkill can be defined as any injury including freeze stress kill, winter desiccation, and low temperature disease to turfgrass plants that occurs during the winter period. The major damages from winterkill were low temperature kill, crown hydration, and winter desiccation. Low temperature kill is caused by air and soil temperature. Soil temperature affect more severe to turfgrass than air temperature because low soil temperature cause fetal damage to turfgrass crown. Crown hydration is a form of winter injury in which intercellular water within the plant freezes and causes physical injury to the cell membrane and wall. This is eventually resulted in dehydration of cell. Winter desiccation is the death of leaves or whole plants due to drought during the winter period. To reduce winterkill damage, cultivar selection is very important. If changing cultivar is not allowed, cold temperature hardiness needs to be increased by providing nutrients especially phosphorus and potassium in the late fall. Turf cover is effective way to reduce winterkill damage. Remaining snow is positive process to reduce winterkill damage by insulating soil temperature. The previous researches reported many materials as turf cover such as straw, polypropylene, polyester, and wood mat. Aeration and topdressing is one of the process against winterkill. Both methods are mainly conducted to reduce thickness of thatch layer. In recent, relatively new materials called black or winter topdressing sand are used to protect soil temperature from low air temperature and thaw ice crystal that may remain in soil.

• Korean Journal of Breeding Science
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• v.40 no.4
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• pp.512-516
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• 2008

A new naked oat cultivar 'Choyang' (Avena sativa L.) was developed by the breeding team at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2007. It was derived from a cross between 'Sikyonggwiri' and 'Gwiri23'. The cultivar, Sikyonggwiri is early heading while the breeding line Gwiri23 has a high yielding potential with large-size grain. Bulk method combined with pedigree selection program was employed in subsequent generations, and the promising line SO96025-B-303-44-2-5 was selected for agronomic performance in 2002. The line showed both high yield and good husking rate of seed in the Yield Trial tested at Suwon in 2003 to 2004, and was subsequently designated as 'Gwiri57'. Gwiri57 was evaluated for winter hardiness, earliness, and yield in four locations, Gimje, Iksan, Jeongeup and Jinju from 2005 to 2007 and was released as Choyang. Choyang headed 11 days earlier and matured 5 days earlier than the check cultivar 'Sunyang' in the paddy field condition. The new cultivar Choyang had 97 cm of culm length and 23.4 cm of spike length, 658 spikes per $m^2$, 75 grains per spike, 28.8 g of 1,000-grain weight, and 636 g of test weight. Choyang showed better winter hardiness than that of the check cultivar Sunyang, and similar seed quality to the check cultivar in respect to crude protein (12.9%) and ${\beta}$-glucan content (4.7%). However, it showed higher husking rate than the check cultivar. The grain yield of Choyang in the regional yield trial for 3 consecutive years was averaged $4.67MT\;ha^{-1}$, which was 38% higher than that of the check cultivar Sunyang. Choyang is recommended for the fall sowing cropping only in the southern area where daily minimum mean temperatures are averaged higher than $-4^{\circ}C$ in January, and is not recommended the in mountain area where frost damage is presumable.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.4
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• pp.121-131
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• 2008

This study was conducted to delineate temporal and spatial patterns of potential risk of cold injury by combining the short-term cold hardiness of Campbell Early grapevine and the IPCC projected climate winter season minimum temperature at a landscape scale. Gridded data sets of daily maximum and minimum temperature with a 270m cell spacing ("High Definition Digital Temperature Map", HD-DTM) were prepared for the current climatological normal year (1971-2000) based on observations at the 56 Korea Meteorological Administration (KMA) stations using a geospatial interpolation scheme for correcting land surface effects (e.g., land use, topography, and elevation). The same procedure was applied to the official temperature projection dataset covering South Korea (under the auspices of the IPCC-SRES A2 and A1B scenarios) for 2071-2100. The dormancy depth model was run with the gridded datasets to estimate the geographical pattern of any changes in the short-term cold hardiness of Campbell Early across South Korea for the current and future normal years (1971-2000 and 2071-2100). We combined this result with the projected mean annual minimum temperature for each period to obtain the potential risk of cold injury. Results showed that both the land areas with the normal cold-hardiness (-150 and below for dormancy depth) and those with the sub-threshold temperature for freezing damage ($-15^{\circ}C$ and below) will decrease in 2071-2100, reducing the freezing risk. Although more land area will encounter less risk in the future, the land area with higher risk (>70%) will expand from 14% at the current normal year to 23 (A1B) ${\sim}5%$ (A2) in the future. Our method can be applied to other deciduous fruit trees for delineating geographical shift of cold-hardiness zone under the projected climate change in the future, thereby providing valuable information for adaptation strategy in fruit industry.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.29-40
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• 2019

In Korea kiwifruit growing area is limited to southern coastal region and Jeju island, partly due to the lack of information on their cold hardiness in winter. This study was carried out to investigate cold hardiness of Korean kiwifruit cultivars in a period of dormancy for using it as preliminary data to expand the cultivation area of kiwifruit in Korea. A total of five kiwifruit cultivars in two species and hybrid, Actinidia deliciosa ('Hayward' and 'Garmrok'), A. chinensis ('Goldone') and A. arguta hybrid ('Bangwoori' and 'Skinny Green') were subjected to five freezing treatments of -12℃, -15℃, -18℃, -21℃ and -24℃. Cell membrane damage in all cultivars initiated in -18℃/32h and cell membrane stability was lost in -24℃ in most cultivars, except for 'Skinny Green'. Cold hardiness was estimated by 50% lethal temperature (LT₅₀) which was determined by triphenyl tetrazolium chloride (TTC) reduction. In branches, LT₅₀ was -15℃ in 'Hayward' and 'Garmrok', -18℃ in 'Bangwoori' and -21℃ in 'Goldone.' The LT₅₀ of buds on 'Hayward' and 'Garmrok' was 56 and 42 hours in -15℃ and 4 and 11 hours in -18℃, respectively; however, LT₅₀ of buds on 'Goldone' was 51 hours in -18℃ and that on 'Bangwoori' was 3 hours in -24℃. Cold hardiness results imply that it may be difficult for cultivars in A. deliciosa such as 'Hayward' and 'Garmrok' to be grown in the north of southern coastal region in Korea; however, it can be possible for several cultivars in A. chinensis and A. arguta hybrid to be grown in the northern part of Korean kiwifruit belt if cold tolerance in the thaw is confirmed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.7-11
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• 1991

Field experiment was conducted to examine the winter hardiness and forage productivity of Chinese milkvetch (Astragalus sinicus L.) varieties at the research farm of Korea University in Kyunggi province. Collected variety Nonsan, Imsil, Jangheung, Chungnam, Joongsan and introduced PI241587 were tested to untreated control and vinyl mulching conditions during winter season. Effect of vinyl mulching treatment was found no statistical significance in this experiment. Winter survival of six Chinese milkvetch varieties at the untreated control was average 88%. Variety Nonsan and Imsil showed higher fresh and dry weights than other varieties both on May 6 and 21 harvest. Average fresh weight per l0a of six varieties at the untreated control was 1,583kg on May 6 and 4,017kg on May 21 harvest. Crude protein content of dry matter of the varieties was average 21.3% on May 6 and 19.2% on May 21 harvest. However, average crude fiber content of the dry matter on May 6 was lower than that of May 21 harvest.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.1
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• pp.1-6
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• 2008

Korditwo is a new orchardgrass(Dactylis glomerata L.) variety developed by the National Institute of Animal Science(NIAS) in 2005. To develope the new variety of orchardgrass, 5 superior clones, Dg8533, Dg9518, EDg9133, U8504 and U8519, were selected and polycrossed for seed production. That synthetic variety was designated newly as "Korditwo", and it's agronomic growth characteristics and forage productivity were examined at Suwon from 2001 to 2002, and regional yield trials were conducted in Suwon, Pyungchang, Youngju, Iksan, and Jeju from 2003 to 2005, respectively. "Korditwo" showed medium type growth habit in fall and spring and short in length of flag leaf and upper internode. Plant height of "Korditwo" was similar to that of standard variety, "Ambassador" and heading date was 4 days later than 14th May compared to Ambassador. Characteristics such as winter hardiness, lodging tolerance, disease resistance of "Korditwo" were stronger or better than those of Ambassador, specially in winter hardiness and lodging tolerance. "Korditwo" showed 10% higher dry matter yield(11.3 ton/ha) compared to Amabassador. Nutritive value was appeared to be similar in both varieties.

• Korean Journal of Agricultural Science
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• v.6 no.2
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• pp.112-118
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• 1979

This experiment was carried out to evaluate the effect of potassium application level for pasture management in Chungnam area. The results obtained were as follows. 1. The seedling establishment of pasture species was slightly depressed by high potassium application. 2. By increasing potassium application level, the winter hardiness of pasture species increased. 3. The forage yield of pasture species was more increased in legume single seeding than grass single and mixed seeding by higher potassium application. 4. The $K_2O$ content in forage was increased markedly by increasing potassium application level on grass single block. 5. The results obtained from this experiment indicated that potassium application level much effective on the winter hardiness of pasture species and forage yield specially in legume single seeding and adequate amount of potassium would be 20kg per 10a in this area.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.1
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• pp.6-11
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• 1991

In order to classify the varieties by the characters to evaluating potential winter hardiness was examined using the relationships between autumn growth of seedling plants and the dry weight of plant(DW), and yield components of 1st cutting in 16 varieties of perennial ryegrass grown under individual plant basis.The results are summarized as tollows:1. The dry weight of plant(L)W) was positively correlated with the number of tillers of seedling plants, but negatively correlated with seedling vigors of plants in autumn growth. 2. The dry weight of plant(L)W) indicated positively significant correlations with the dry weight of heading tillers(HDW), number of tillers per plant(NT), number of vegetative tillers(VNT), number of heading tillers(HNT), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.3. Relative tiller appearance rates(RTAK) corresponded with the seasonal patterns of tillering ability. Thevariety with a low values of relative tiller appearance rates(RTAR) showed vigorous tillering ability inautumn growth, but the variety with a high values of relative tiller appearance rates(KTAR) showedvigorous tillering ability in spring growth.4. The dry weight of plant per relative tiller appearance rates(DW/RTAR) indicated positively significant correlations with the dry weight of plant(DU7, plant length(PL), dry weight of heading tillers(HDW), number of tillers per plant(NT), number of heading tillers(HNrr), dry weight of a tiller(WT) and heading rates(HR) of 1st cutting.5. The varieties were classified into 2 groups by the dry weight of plant per relative tiller appearance rates(DW/RTAR). Thus. Manhattan, P-2, Tonga, Tove, Hella. I'eramo and Fiesta belong to the group of DW/RTAII>l. 0, and Maprima, Caliente, Tempo, Gambit, Magella, Prana. Reveille, Barlet and Bravo belong to the group of DW/RTAR

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.4
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• pp.235-241
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• 2004

There is a growing concern about the possible increase in inter-annual variation of minimum temperature during the winter season in Korea. This view is strengthened by frequently reported freezing injury to dormant fruit trees, while warmer winters have prevailed recently. The January minimum temperature record at fourteen weather stations was analyzed for 1951-2000. The results showed no evidence of increasing standard deviation at 3 locations between 1951-1980 and 1971-2000, while the remaining 11 stations showed a trend of decreasing standard deviation for the two periods. An empirical model explaining the spatial variation of the standard deviation was derived by regression analysis of 56 stations' data for 1971-2000. Daily minimum temperature and the site elevation may account for 68% of the observed variations. We applied this model to restore the average standard deviation of the January minimum temperature for 1971-2000, and the result was used to produce gridded minimum temperature data for the recurrence interval of 10 and 30 years at 250m resolution. A digital form of the plant hardiness zone map may be developed from this product for site-specific selection of adapted plant species.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.203-203
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• 2022

A new winter wheat(Triticum aestivum L.) cultivar "Hwanggeumal" was developed by the NICS(National Institute of Crop Science), RDA(Rular Dvelopment Administraion) in 2019. It was derived from a cross of the "Jokyoung//Kauz/Rayon" and "Jopoom" in 2008. It had advanced generation through bulk and pedigree method for seven years and designated line name "Jeonju398" after AYT(Advance Yield Trial) test for two years. And "Hwangeumal" was designated variety name after RYT(Regional Yield Trial) test in eight locations around Korea for two years from 2018 to 2019. Its heading date was April 19 and maturity date was May 31, which were similar to Jokyoung. "Hwanggeumal" had shorter plant height(75 cm) and spike length(7.1 cm), spikes per m²(699) and lower 1,000 grain weight(44.2 g) than "Jokyoung"(78 cm, 8.2 cm, 776, 46.6 g, respectively). "Hwanggeumal" was showed weak to winter hardiness and susceptible to powdery mildew but tolerance to PHS(Pre-harvest sprouting). The average grain yield in the AYT was 6.2 ton/ha, which were 10% more than "Jokyoung" And in the RYT was 5.1 ton/ha in upland and 4.4 ton/ha in paddy field, which were lower than "Jokyoung", respectively. "Hwanggeumal"s flour yield (71.4%) and flour lightness (91.82) showed similar to "Jokyung" and higher protein content (14.0%) and gluten content (10.3%) and SDS-sedimentation volume (60.3ml). These result showed that the "Hwanggeumal" dough strength of flour is strong than "Jokyung". "Hwanggeumal"s HMW-GS(High molecular weight gluten subunits) composition are Glu-D1 (5+10), Granule-bound starch synthase(GBSS) composition are Wx-A1 (a), Wx-B1 (b), Wx-D1 (a) and composition of Puroindolines are Pina-D1(a), Pinb-D1(b).