• Journal of Bio-Environment Control
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• v.28 no.4
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• pp.352-357
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• 2019

In this study, we investigated the limit temperature range which is effective for dormancy release of 'Hongro' and 'Fuji' apples during the endodormancy period. The germination rate was 50% or more in all treatments except of 'Hongro' $-5^{\circ}C$ treatment. The germination rate of 'Fuji' was 86.3% at the temperature of $-5^{\circ}C$. The concentrations of carbohydrate and mineral components were significantly different between treatments but did not show any tendency or specific change. However, the sorbitol contents of 'Hongro' $-5^{\circ}C$ treatment were higher at 29.62 mg/g than those of 'Fuji', which was not affected for dormancy release. The results of hormone analysis showed that ABA(abscisic acid) and JA(jasmonic acid) in 'Hongro' $-5^{\circ}C$ treatment were respectively 176.48 and 15.72 ng/g. ABA, JA and SA(salicylic acid) contents in 'Fuji' apple tree were significantly lower than those of 'Hongro'. As a result of this study, the limit temperature range effective for dormancy release was different according to the varieties, and 'Hongro' did not affect with 30.3% of germination rate at $-5^{\circ}C$. However, 'Fuji' is 86.3% even at $-5^{\circ}C$ it was suggested that 'Fuji' had a chilling accumulation for dormancy release.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.349-356
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• 2013

A set of experiments were conducted to determine the zero temperature and total effective temperature for the summer diapause and post-diapause development of Matsucoccus thunbergianae Miller et Park (Hemiptera: Margarodidae) which infests the Japanese black pine, Pinus thunbergii. The diapausing first instar nymphs were kept in cool storage during three separate times, each starting from May 4th, June 19th, and August 15th of 2002. Cool storage temperatures were 2.5, 5.0, 7.5, 10.0, 12.5 and $15.0^{\circ}C$. The nymphs were chilled for 10, 20, 30 or 40 days in the first two sets of experiments. In the third experiment, nymphs were chilled for 3, 6, 9 or 12 days. Molting into the second instar nymphs was examined every 10 days, starting at 20 days after taken out from the cool storage. Optimum temperature range of the diapause development was between 7.5 and $10^{\circ}C$, where diapause development was completed in 40, 20, and 6 days by the insects chilled from May 4th, June 19th and August 15th, respectively. Comparing the three sets of experiments with different chilling periods, zero temperature for diapause development was calculated as $29^{\circ}C$. Effective temperature for diapause development was 964 degree days, and it was estimated that nymphs completed their diapause development by September 8th in nature. Under natural temperature conditions >50% eclosion into the second instar occurred on November 9th. Zero temperature for post-diapause development was $10^{\circ}C$, and total effective temperature for post-diapause development until the molt into the second instar was 391 degree days.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.449-462
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• 2021

We analyzed the effects of temperature on the survival, development, and reproduction of the non-diapause Asian corn borer, Ostrinia furnacalis (Lepidoptera: Crambidae). A 16:8 h light:dark photoperiod was supplied to the non-diapause stages of O. furnacalis. The insects were raised on an artificial diet at seven constant temperatures between 15 and 35℃ for immature stages, and eight temperatures between 13 and 33℃ for the adult stage. The survival rate of eggs exceeded 70% at all temperatures, whereas survival of larvae was as low as 7.4% at 15℃. The developmental periods of the immature stages decreased with increasing temperature, but the larval period did not decrease further at 35℃. The pupal weight increased with increasing temperature, but the female weight decreased at 35℃. Variations with different last larval instars within the colonies at different temperatures were observed. Adults produced offspring at all tested temperatures. Adult longevity and the pre-oviposition and oviposition periods decreased with increasing temperature, but the pre-oviposition period increased at 33℃. Total fecundity exceeded 400 viable eggs at 22℃ and 31℃. The mean daily fecundity during the oviposition period and the mean daily fecundity on the day of oviposition increased with increasing temperature, but decreased at 33℃. Daily fecundity sharply increased at earlier adult ages and slowly decreased thereafter. The simulated oviposition frequency was greatest at 22℃. The lower developmental threshold temperatures were estimated to be the lowest at 9.7℃ for the first instar larva and the highest at 14.7℃ for the 5th to last instar larval stage, using a linear model.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.402-403
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• 2000

적조의 원인생물에는 분류학적으로 다양한 종류가 속하며, 이 중 와편모조류는 대표적이라 할 수 있다 (박 등, 1988). 일부 와편모조류는 생활사 중 휴면포자로 해양퇴적토의 표층에서 일정기간 생존하다가 외부환경이 좋아지면 유영세포로 발아하여 다시 번무를 일으킴으로써 적조의 발생 분포 지역의 확대와 발생빈도를 더욱 증가시킨다 (Steidinger and Haddad, 1981; Hallegraeff, 1993; Ishikawa and Taniguchi, 1994; Nehring, 1995). (중략)

• Korean journal of applied entomology
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• v.32 no.2
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• pp.139-150
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• 1993

This study was conducted to investigate the effect of 20-hydroxyecdysone on diapausing pupae of Hyphantna cunea. Treatment of 20-HE at the dosage of 5 $\mu$ g or higher/g live weight terminated diapause in about 50% of Hyphantna cunea pupae treated, and some malformed adult emerged at dosages of 10 or 12.5 $\mu$g of 20-hydroxyecdysone/g live wt. The maximum concentration of 20-hydroxyecdysone in the whole body of normally developing pupae was about 3.2 $\mu$g/g on the 6th day after pupation, and in that of diapausing pupae treated with 20 -HE about 4.1 $\mu$g/g on the 6th day after the treatment. But diapausing pupae showed a low level( 1.7 $\mu$g/g) of maximum 20-HE concentration. In diapausing pupae treated with 20- HE, glycongen content was lower than in normally developing pupae, but the changing pattern was similar to that observed in normally developing pupae. Glucose(and/or sorbitol) and trehalose content of 20-HE-injected pupae reached the maximum value on the 6th day after the injection, which were higher than those of normally developing pupae. The amount of soluble haemolymph proteins was lower but the total soluble protein content of haemolymph-rernoved whole body was higher in 20-HE-injected pupae than that in normally developing pupae.

• 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.39 no.3
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• pp.270-277
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• 1994

This study was conducted to investigate change of seed dormancy during storage in rice. The result of germination rate observed at different storage duration after harvest indicated that two Japonica rice varieties, Sangpungbyeo and Hwaseongbyeo, tow sare type local varieties, Jakwangdo and Mongeunsare, and a Tongil type rice, Samgangbyeo, showed no dormancy in rice seed harvested at 40 days after heading, However, weak dormancy was found in matured rice seed of Sobaekbyeo and Odaebyeo, and strong seed dormancy was found in Jungwonbyeo, IR-20 and IR-42. Rice seed stored for 30 days after harvest at 2$0^{\circ}C$ constant temperature or 25/15$^{\circ}C$ of day /night temperature fluctuation showed higher germination rate above 90% in all varieties tested. But germination rate of seeds stored at 4$^{\circ}C$ for 30 to 180 days showed varietal difference, higher in rice varieties having weak seed dormancy and lower in strong dormancy varieties. Days to 80% germination and average days for germination were shortened by storage for 30 to 180 days after harvest at 2$0^{\circ}C$, 4$^{\circ}C$ with RH 40% or day /night 25/15$^{\circ}C$ temperature condition in all rice varieties tested, but the degree of acceleration was lower at the condition of 4$^{\circ}C$ with RH 40%.

• Korean journal of applied entomology
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• v.23 no.1 s.58
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• pp.42-48
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• 1984

The developments of overwintering larvae of the peach fruit moth, Carposina niponensis Walsingham, were studied in Suweon. Among fully grown larvae leaving from apple fruit, the earliest diapause larva was observed late July, about $50\%-diapause$ in middle August and $100\%-diapause$ in early September. Induction of the diapause seemed to have relationships with the time of oviposition: the incidents of the diapause started with the larvae grown from the eggs which had been laid in late June or late July depending on the prevailing weather condition. The termination of the diapause seemed to be in early December, and almost all of the larvae incubated after January were pupated. For the breakage of the diapause, it required chilling period more than one month, and the most effective temperature seemed to be $5\~10^{\circ}C$, while the temperature lower than $0^{\circ}C$ seemed to be inhibitory, if not at all. The overwintered larvae started to pupate in middle May, and the developments of the over-wintered larvae were affected by the temperature as well as the moisture contents of soil in the spring. The dry condition of soil increased the mortality of the developing larvae.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.61-71
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• 2009

Most deciduous trees in temperate zone are dormant during the winter to overcome cold and dry environment. Dormancy of deciduous fruit trees is usually separated into a period of rest by physiological conditions and a period of quiescence by unfavorable environmental conditions. Inconsistent and fewer budburst in pear orchards has been reported recently in South Korea and Japan and the insufficient chilling due to warmer winters is suspected to play a role. An accurate prediction of the flowering time under the climate change scenarios may be critical to the planning of adaptation strategy for the pear industry in the future. However, existing methods for the prediction of budburst depend on the spring temperature, neglecting potential effects of warmer winters on the rest release and subsequent budburst. We adapted a dormancy clock model which uses daily temperature data to calculate the thermal time for simulating winter phenology of deciduous trees and tested the feasibility of this model in predicting budburst and flowering of Niitaka pear, one of the favorite cultivars in Korea. In order to derive the model parameter values suitable for Niitaka, the mean time for the rest release was estimated by observing budburst of field collected twigs in a controlled environment. The thermal time (in chill-days) was calculated and accumulated by a predefined temperature range from fall harvest until the chilling requirement (maximum accumulated chill-days in a negative number) is met. The chilling requirement is then offset by anti-chill days (in positive numbers) until the accumulated chill-days become null, which is assumed to be the budburst date. Calculations were repeated with arbitrary threshold temperatures from $4^{\circ}C$ to $10^{\circ}C$ (at an interval of 0.1), and a set of threshold temperature and chilling requirement was selected when the estimated budburst date coincides with the field observation. A heating requirement (in accumulation of anti-chill days since budburst) for flowering was also determined from an experiment based on historical observations. The dormancy clock model optimized with the selected parameter values was used to predict flowering of Niitaka pear grown in Suwon for the recent 9 years. The predicted dates for full bloom were within the range of the observed dates with 1.9 days of root mean square error.

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.6 no.12
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• pp.83-89
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• 1985

겨울동안 딸기재배의 작형은 딸기가 휴면기간이 매우 짧으면서 꽃눈분화가 조속히 이루어지는 품종을 선택하여 재배하는데 일반적으로 촉성, 반촉성 및 억제재배 등이 있으며 촉성재배는 비닐이나 섬피 등 보온을 실시하여 11월$\~$1월부터 2$\~$3월에 걸쳐서 수확을 목적으로 재배하는 작형이다. 반촉성재배는 촉성재배보다 보온을 늦게 시작하여 촉성재배의 수확말기인 3$\~$4월에 수확하여 출하하는 재배형이다. 억제재배에서와 같이 보통육묘를 실시해서 월동시킨 다음 봄에 생육이 시작하기 전인 2월 하순경에 모를 굴취하여 0$^{\circ}C$내외의 환경하에 장기간 저장하여 강제휴면을 시켰다가 8$\~$9월에 정식한 후 10$\~$11월경에 수확하는 작형이다. 이들 기본작형을 변형시켜 다시 세분화된 재배형으로 나눌 수도 있다. 본란에서는 현재 수익성이 높고 비교적 안전한 딸기 반촉성재배에 대하여 설명하고자 한다.