• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.3
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• pp.185-191
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• 2005

An accurate prediction of dormancy release and bud burst in temperate zone fruit trees is indispensable for farmers to plan heating time under partially controlled environments as well as to reduce the risk of frost damage in open fields. A thermal time-based two-step phenological model that originated in Italy was applied to two important grapevine cultivars in Korea for predicting bud-burst dates. The model consists of two sequential periods: a rest period described by chilling requirement and a forcing period described by heating requirement. It requires daily maximum and minimum temperature as an input and calculates daily chill units (chill days in negative sign) until a pre-determined chilling requirement for rest release is met. After the projected rest release date, it adds daily heat units (anti-chill days in positive sign) to the chilling requirement. The date when the sum reaches zero isregarded as the bud-burst in the model. Controlled environment experiments using field sampled twigs of 'Campbell Early' and 'Kyoho' cultivars were carried out in the vineyard at the National Horticultural Research Institute (NHRI) in Suwon during 2004-2005 to derive the model parameters: threshold temperature for chilling and chilling requirement for breaking dormancy. The model adjusted with the selected parameters was applied to the 1994-2004 daily temperature data obtained from the automated weather station in the NHRI vineyard to estimate bud burst dates of two cultivars and the results were compared with the observed data. The model showed a consistently good performance in predicting the bud burst of 'Campbell Early' and 'Kyoho' cultivars with 2.6 and 2.5 days of root mean squared error, respectively.

• Journal of Environmental Science International
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• v.30 no.1
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• pp.77-85
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• 2021

This study was carried out to establish optimal conditions for breaking dormancy of Agastache rugosa O. Kuntze seeds. A series of experiments according to seed maturity and treatment with plant growth regulators were performed to improve germination percentage and synchronize germination of the seeds. In addition, it was conducted to test whether the useful effect of seed treatment before sowing leads to healthy seedling and early vigorous growth. The average seed size was 1.85 mm (length) × 0.82 mm(width). The seed size was much smaller than other vegetable seeds. Seeds colorappeared dark brown, the shape of the seeds was oval and the weight of 1,000seeds was 352.8 mg. The optimum germination temperature was 22℃. Light exposure during germination did not affect germination promotion, suggesting that A. rugosa seeds are a kind of dark germinating seeds. Seed dormancy lasted for 40 days after harvesting, and GA3 treatment of dormant seeds could break dormancy. There were significant differences in germination percentage and rate according to the maturity of seeds. The germination percentage of mature seeds was 10 - 18% higher than that of immature seeds, and germination rate was 2 days faster. GA3 treatment during growth regulator treatment improved germinability, but BAP or ethephone treatment did not. The optimal growth regulator concentration of for germination was the combination treatment of 100 mM GA3 ＋ 100 mM BAP.

• The Korean Journal of Ecology
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• v.25 no.2
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• pp.93-100
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• 2002

In order to analyze the life cycle of A. artemisiifolia var. elation dormancy and some environmental factors inducing germination of the seeds were examined. The results were as follows : Dormancy of fertile seeds was broken in part within a month after seed collection in case of adequate moisture and alternating temperature was also effective in breaking dormancy. The temperature range, which allow germination was 12℃ ∼ 32℃. Optimum temperature for germination was 24℃. The seed of A. artemisiifolia var. elatior was light-independent. The difference of storage period appeared to have no particular effect on the viability of seeds at any time during the 9-month storage period. In the increasing temperature(IT) regime, A artemisiifolia var. elatior seeds started to germinate at 16℃, showing the higher temperature the greater germination rate, the final germination percentage was 99.34%. On the other hand, in the decresing temperature(DT) regime, seeds began to germinate at 20℃ with the 1.34% germination. An induced dormancy occurred at 12℃ making the 5.34% fecal germination in the DT regime. Low temperature was more effective to break dormancy than higher temperature Seeds of A. artemisiifolia var. elatior seems to be germinated in mid to late autumn or germination delayed until following spring. The above results suggest these variation of germination response in diverse environmental factors seems to be a physiological strategy to maintain their existence and to reproduce in the extreme thermal variation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.4
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• pp.445-450
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• 1983

To investigate the effect of harvest time after heading, storage temperature and duration on the dormancy and germination in barley cultivars, the kernels were collected at 5 day intervals from 20 days after heading until 35 days. The kernels were dried at 2$0^{\circ}C$ for 7 days and storaged in freezing chamber (-15$^{\circ}C$). The kernels germinated better at 15$^{\circ}C$ than at $25^{\circ}C$, and 1% $H_2O$$_2$ and 3 ppm GA$_3$ treatments gave much higher germination percentage than non-treatment; $H_2O$$_2$ and GA$_3$ treatments were good for promoting germination of immature harvested kernels. Germination rate index were significantly correlated with germination percentage under $25^{\circ}C$ and 15$^{\circ}C$ temperature conditions. Hangmi, Jogangbori and Muanbori had deep or slight dormancy at the different harvesting time, especially Dusan #8 had the deepest dormancy. The dormancy broke more rapidly under 3$0^{\circ}C$ than 2$0^{\circ}C$ storage conditions, so high temperature accelerated dormancy breaking. Those results showed that dormancy was various with the cultivars, harvesting time, storage temperature and storage duration.

• Proceedings of the Korean Society of Crop Science Conference
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• 1986.06a
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• pp.82-83
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• 1986

• KOREAN JOURNAL OF CROP SCIENCE
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• v.22 no.2
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• pp.18-22
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• 1977

Germination ability of a japonica and 15 indica$\times$japonica varieties was tested at day/night tempuratures of 25/2$0^{\circ}C$ and 12/12$^{\circ}C$. Germination ability of a japonica variety, "Jinheung" and two indican$\times$japonica varieties. "Suweon ＃251" and "Suweon ＃278" was greater than that of other indica$\times$japonica varieties tested. Germination pattern of varieties was made into 4 groups.ieties was made into 4 groups.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2002.04a
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• pp.131-136
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• 2002

포도 2기작 재배는 아열대 지방인 대만 등에서 온난한 기후를 이용하여 실시되고 있다. 최근에 와서는 일본에서도 시설내 환경조절을 통하여 거봉포도를 한 나무에서 1년에 2회 생산하는 2기작 재배가 시도되고 있다. 2기작 재배 기술이 확립되면 수익의 증가가 기대됨과 동시에 하우스의 이용효율이 높아진다. 또한 수세도 쇠약해지지 않아 정상적인 가온재배에 비해서 수세 유지가 양호하다(Yamamoto, 1993). (중략)

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.171-175
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• 1996

The objective of this study is to promote germination for mass cultivation of Adenophora triphylla. After the seed soaking for I day in BA and $GA_3$ solution, seed germination was effectively promoted in the treatment of 500mg/L $GA_3$ and the highest germination rate was 94%.The average germination days were 1.5days earlier than those of non-treated seeds. In a chemicals treatment, seed germination rate was 54% in 1% $KNO_3$ treatment but KOH treatment was no significantly effected. The durations of chilling treatment for breaking of dormancy were longer than 2weeks. The optimal temperature for germination was $25^{\circ}C$. The promotion of seed germination is presumed to be due to the breaking of dormancy by $GA_3$, chilling treatment rather than seed coat maceration by KOH or $KNO_3$ treatments.

• Korean Journal of Medicinal Crop Science
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• v.11 no.5
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• pp.347-351
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• 2003

This experiment was carried out to study the optimal chilling period for breaking the physiological dormancy of dehisced E. senticosus seeds and to investigate the critical seeding date in Kangwondo. Storage at $5^{\circ}C$ for 85 days was most effective in breaking dormancy of dehisced seeds, but didn't germinated synchronously. Only 28.1% of undehisced seeds germinated after 125 days of low temperature storage. For improving seedling survival rate in the field, 50% shading was more effective than 30% shading. Delayed seeding date resulted in decreased seedling fresh weight, dry weight, leaf area and root length, but seeding date has no significant affecte on stem length.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.488-494
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• 2001

Seedlings of strawberry, 'Reiko' were planted in plastic pots of 24 cm in diameter in the middle of September in 1995, 1996, and 1997. Ten plants were transferred to greenhouse with artificial illumination at 5-day interval from late September to late January. The deepest dormancy of 'Reiko' in Daegu area was found to be on November 5, October 25, and October 31 in 1995, 1996, and 1997, respectively. The time for moving plants to make the plants grow in semi-dormant state in the greenhouse occurred between Nov. 10 and Nov. 20 in both 1995 and 1996, and between Nov. 10 and Nov. 30 in 1997. The time passing approximately 100-200 cumulative hours of exposure to below $5^{\circ}C$ canopy temperature from the peak dormancy, which is required for breaking dormancy of 'Reiko', was between November 16 and 25 in 1996, and November 24 and December 5 in 1997. 'Reiko' yielded high every year when seedlings were moved into greenhouse during the period of October to November. The plants gave good response to forcing culture under lighting. The right time for moving plants into greenhouse in semi-forcing culture appeared to be the time passing 50-150 cumulative hours of exposure to below $5^{\circ}C$ canopy temperature from the peak dormancy.