Phenotypic selection for seed dormancy in white snakeroot (Eupatorium rugosum)

Lau, Joann M.,Robinson, David Lowell The Korean Society of Weed Science and The Turfgra 2010 Weed Biology and Management Vol.10 No.4

Eupatorium rugosum (Ageratina altissima), commonly known as white snakeroot, is a weedy plant that invades woodland areas in North America, Korea, and Japan. In order to examine the inheritance of seed dormancy in this species, seeds from a single population were screened for their differential germination response to stratification. After two cycles of recurrent selection, the seed from the shallow-dormant lines had 4.4 times greater germination prior to stratification than did the seed from the deep-dormant lines. The seed from the deep-dormant lines showed 3.4 times greater germination after stratification, compared to the seed from the shallow-dormant selections. This suggests that primary dormancy in the seed of white snakeroot is under some degree of genetic control. This perennial species produces overwintering rhizomes that give rise to adventitious, vegetative buds each spring. The plants selected for the production of seeds with lower levels of dormancy in the fall were observed to generate rhizomatous buds that were released from dormancy earlier in spring, compared to the plants that produced seeds with higher levels of dormancy. A statistically significant positive correlation also was observed between seed and bud dormancy in a naturally occurring population of white snakeroot. Common regulatory elements might be influencing dormancy in both the seeds and vegetative buds of this species.

경남지역 왕벚나무의 개화에 미치는 온도영향의 수치화

정경희,정병룡 한국화훼학회 2019 화훼연구 Vol.27 No.4

This experiment was conducted to predict the flowering time of cherry blossoms. The phenological model was used to predict the accurate flowering time, and investigate the daily temperature to calculate the chilling requirement for the flowering of Prunus yedoensis Matsum. Twigs of several decades-old trees were collected on January 3, 2010 and were kept in a 2℃ refrigerator. From January 16, 2010 onward, more twigs were collected from the same field every week. Twigs of both groups were laid in water in a 25℃ growth chamber. To determine the bud-burst date and the period required for dormancy break, the state of flower buds was observed every day. The daily maximum and minimum temperatures were also collected to calculate the accumulated degree hour of the chilling requirement until the dormancy was broken. To fined out the threshold temperature and chilling requirement for the approximate flowering date, the equation was used to set the threshold temperature from 5℃ to 9℃ at intervals of 0.1℃ and calculate chill days and anti-chill days repeatedly. The equations for calculating daily Cd and Ca, are given in Table 1 for each of the five cases. Based on this prediction model, the most optimized threshold temperatures and chilling requirements were predicted to be 5.8℃ and -116.8. The broken day of the rest was estimated to be February 17. The model, used for predicting the flowering day of Prunus yedoensis Matsum. from 2012 - 2019, showed that RMSE is 2.5 days when using the measured temperature and 4.4 days when used the average March temperature of 30 years (1980 – 2010). The results showed improvement compared with the previously announced predictions of flowering days. 본 연구는 벚꽃의 개화시기를 예측하기 위해 수행하였다. 정확한 개화시기를 예측하기 위하여 생물계절 모형을 사용하 였으며, 왕벚나무의 개화에 필요한 저온요구량을 계산하기 위 하여 매일의 온도를 조사하였다. 실험을 위하여 2010년 1월 3 일 수십년 된 왕벚나무에서 가지를 채취하여 2℃ 냉장고에 저 장하였다. 그리고 1월 16일부터 매주 외부에서 채취한 가지와 함께 25℃ 생장상에 수삽하여 발아일과 휴면타파에 필요한 기간을 도출하기 위하여 매일 관찰하였다. 또한 휴면타파 시까 지의 저온요구량을 누적하고 계산하기 위하여 일최고온도와일최저온도를 조사하였다. 관측된 개화일과 일치하는 예측일 을 구하기 위하여 기준온도를 5∼9℃로 0.1℃ 간격으로 반복 하여 구동하였다. 가장 최적의 모형은 휴면타파일이 2월 17 일, 기준온도 5.8℃, 저온요구량 -116.8이었으며, 2012~2019년 실측값을 이용한 모델은 RMSE 2.5일, 30년 평균 온도를 이용 한 예측 모델은 RMSE가 4.4일로 이 기간 예보된 RMSE 5.0일보다 개선된 결과를 보였다.

Quantification of Temperature Effect on Prunus yedoensis Matsum. Flowering in Gyeongnam Province of Korea

Kyong Hee Joung,Byoung Ryong Jeong 한국화훼학회 2019 화훼연구 Vol.27 No.4

본 연구는 벚꽃의 개화시기를 예측하기 위해 수행하였다. 정확한 개화시기를 예측하기 위하여 생물계절 모형을 사용하였으며, 왕벚나무의 개화에 필요한 저온요구량을 계산하기 위하여 매일의 온도를 조사하였다. 실험을 위하여 2010년 1월 3일 수십년 된 왕벚나무에서 가지를 채취하여 2℃ 냉장고에 저장하였다. 그리고 1월 16일부터 매주 외부에서 채취한 가지와 함께 25℃ 생장상에 수삽하여 발아일과 휴면타파에 필요한 기간을 도출하기 위하여 매일 관찰하였다. 또한 휴면타파 시까지의 저온요구량을 누적하고 계산하기 위하여 일최고온도와 일최저온도를 조사하였다. 관측된 개화일과 일치하는 예측일을 구하기 위하여 기준온도를 5∼9℃로 0.1℃ 간격으로 반복 하여 구동하였다. 가장 최적의 모형은 휴면타파일이 2월 17 일, 기준온도 5.8℃, 저온요구량 -116.8이었으며, 2012~2019년 실측값을 이용한 모델은 RMSE 2.5일, 30년 평균 온도를 이용한 예측 모델은 RMSE가 4.4일로 이 기간 예보된 RMSE 5.0일 보다 개선된 결과를 보였다. This experiment was conducted to predict the flowering time of cherry blossoms. The phenological model was used to predict the accurate flowering time, and investigate the daily temperature to calculate the chilling requirement for the flowering of Prunus yedoensis Matsum. Twigs of several decades-old trees were collected on January 3, 2010 and were kept in a 2℃ refrigerator. From January 16, 2010 onward, more twigs were collected from the same field every week. Twigs of both groups were laid in water in a 25℃ growth chamber. To determine the bud-burst date and the period required for dormancy break, the state of flower buds was observed every day. The daily maximum and minimum temperatures were also collected to calculate the accumulated degree hour of the chilling requirement until the dormancy was broken. To fined out the threshold temperature and chilling requirement for the approximate flowering date, the equation was used to set the threshold temperature from 5℃ to 9℃ at intervals of 0.1℃ and calculate chill days and anti-chill days repeatedly. The equations for calculating daily Cd and Ca, are given in Table 1 for each of the five cases. Based on this prediction model, the most optimized threshold temperatures and chilling requirements were predicted to be 5.8℃ and -116.8. The broken day of the rest was estimated to be February 17. The model, used for predicting the flowering day of Prunus yedoensis Matsum. from 2012 - 2019, showed that RMSE is 2.5 days when using the measured temperature and 4.4 days when used the average March temperature of 30 years (1980 – 2010). The results showed improvement compared with the previously announced predictions of flowering days.

Effect of Artificial Heating on Cold Resistance of the Asian Pear Cultivars Chuwhangbae and Niitaka During Winter Period

( Sherzod Rajametov ),( Sam Seok Kang ) 한국육종학회 2014 Plant Breeding and Biotechnology Vol.2 No.1

The purpose of this study was to investigate responses of pear cultivars ‘Niitaka’ and ‘Chuwhangbae’ under short period heating on cold resistance level of flower buds. Experiment was conducted using annual shoots flower bud which were artificially heated (AH) during 72 hour at room condition (18-20℃). To assay for cold resistance, the cultivars were treated and observed under negative temperatures -10, -15, -20 and -25℃ during the winter period in 2012 and 2013. Our findings revealed that ‘Chuwhangbae’ which was treated under control and artificial heating treatments was more resistant to low temperature than ‘Niitaka’ showing decreasing level of flower buds damages by mid-January although in early March an increasing level of damages was observed again. Cold resistant cultivar ‘Chuwhangbae’ responded more sensitively to external environments. This means that ‘Chuwhangbae’ restructures the plant protoplasts and process the transition to the new metabolic energy level in an efficient manner when triggered by effective negative temperatures thereby resulting in hardening process. We assume that this might be closely related with dormancy period, concentration of the mineral elements, water potential and transition processes of metabolism to the new energetic level. With a rise in temperature, cold tolerance in pear cultivars significantly decreased and this is related to intensive development of the floral organs. The chilling requirements for blossoming of ‘Niitaka’ was higher than ‘Chuwhangbae’.

Growth and Flowering Response of Domestic Bred Gypsophila ‘Dream Song’ as Affected by Heating Time in Plain Area

정동춘,이진재,최창학,김정만 한국화훼학회 2017 화훼연구 Vol.25 No.1

This study was investigated the effect of heating time (taken the pots transplanted perennial root in heating greenhouse from Dec. 30 to Mar. 2 as 10 days interval) after 1st cut-flower harvesting on the growth, flowering time, and cut-flower productivity of domestic bred Gypsophila paniculata ‘Dream Song’ in plain area. As the later heating time, the shorter days to shoot emergence and flower budding as the longer exposed to low temperature, and blooming was promoted with increasing the air temperature within greenhouse. Flower stalk length, node number, and stem diameter were inclined to decline in later heating time. In Dec. 30 heating time, node number on a main stem was many, but primary branches number was low due to insufficient breaking of dormancy. Cut flower length was not significantly different as affected by heating time, fresh weight got declined as the later heating time and then drastically decreased in Mar. 2. Cut-flower yield was not significantly different among heating time except for both Dec. 30 insufficiently exposed to low temperature and Mar. 2 shortened the growth duration caused by relatively high temperature. It was thought that the dormancy of ‘Dream Song’ broke after the middle of January under natural low temperature, and the production of second crop should be cultivated within Feb. 20 from mid January.

Dormancy-Breaking Chemicals; Efficiency with Reduced Phytotoxicity

Amnon Erez,Zeev Yablowitz,Arie Aronovitz,Amnon Hadar 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

Breaking Bud Dormancy in Erythronium japonicum Decne. (Liliaceae) by Natural and Artificial Chilling

김신영,이승연,이용하,김기선 한국원예학회 2014 Horticulture, Environment, and Biotechnology Vol.55 No.5

This study was conducted to investigate flower bud differentiation and to determine the chilling requirementsfor bud dormancy breaking and sprouting in Erythronium japonicum Decne. (Liliaceae). Dormant bulbs grown in anopen field were randomly selected from June 2012 to December 2013 for observation of flower bud differentiationand development. The 3-4 year-old bulbs and > 10 year-old bulbs were used for vegetative bud development and flowerbud development, respectively. For natural chilling treatments, the plants were transferred from an experimental fieldto a growth module every month from September to February. Artificial chilling treatments were applied at 5°C for0, 2, 4, 8, and 12 weeks in October and November. The cumulative chill unit (CCU) of low temperatures below5°C was calculated. Flower bud initiation and differentiation in E. japonicum were observed in May, and from Juneto July, respectively, followed by flower bud elongation in August. Sprouting and bud break did not occur throughoutthe experiment when dormant bulbs were transferred from September (0 CCU) to November (450 CCU). However,all plants sprouted when the dormant bulbs were transferred after January (1,794 CCU). Prolonged cold storage alsopromoted sprouting of dormant E. japonicum. No cold storage or 4 weeks (672 CCU) of cold storage at 5°C inOctober did not induce sprouting and bud break. However, when the dormant bulbs were stored at 5°C for 12weeks (2,061 CCU) in October, percent sprouting increased to 72.7%. Chilling treatment for 8 weeks (1,483 CCU)or 12 weeks (2,155 CCU) at 5°C in November resulted in 72.7 and 100% sprouting, respectively. In conclusion, atleast 1,483-1,794 CCU may be recommended for dormancy breaking in the forcing culture of E. japonicum.

Interaction Between time of Nodal Explant Collection and Growth Regulators Determines the Efficiency of Morus alba Micropropagation

Hassanein A.M.,Galal A.A.,Azooz M.M. The Korean Society of Plant Biotechnology 2003 Plant molecular biology and biotechnology research Vol.5 No.4

The hormonal requirement suiting micropropagation of Morus alba during any season throughout the year was studied. Sprouting frequency from axillary buds of M. alba was greatly influenced by the time of explant collection, the highest value was achieved when nodal explants were collected at the end of bud dormancy period (late in March) and cultured on Murashige and Skoog (MS) medium supplemented with low concentration (0.5 mg/L) of BAP, kinetin or IBA (85-68%). In addition, they showed higher axillary bud sprouting on growth-regulators-free medium (49%) than others collected in autumn or winter and cultured on medium supplemented with various growth regulators (47-48%). Regardless of that period, young explants with greenish buds collected in summer exhibiting high sprouting frequency (66%) on MS medium supplemented with 0.5 mg/L kinetin and 0.5 mg/L GA3. Shoot multiplication via adventitious bud formation was achieved when the nodal explants were cultured on MS medium supplemented with 2 mg/L BAP and 0.2 mg/L IBA. Further multiplication via nodal explants of in vitro grown shoots was obtained on MS medium supplemented with 0.5 mglL BAP and 0.5 mg/L GA3. While half strength MS medium supplemented with low concentration (0.5 mg/L) of IBA, IAA or 2,4-D stimulated adventitious root formation, IBA was the best. After transfer the plantlets to the soil, acclimatization for three weeks was essential prerequisite for survival in high frequency (92%). Peroxidase activity is related to break of bud dormancy where maximum enzyme activity was detected when the lateral buds were induced to commence growth under field condition (early in spring) or in vitro.

Chill Unit Models for Predicting Dormancy Completion of Floral Buds in Apple and Sweet Cherry

곽성희,Denise Neilsen 한국원예학회 2013 Horticulture, Environment, and Biotechnology Vol.54 No.1

Temperature-controlled experiments were conducted to determine the relative contribution of temperatures to dormancy completion of floral buds in ‘Gala’ apple (Malus domestica Borkh.) and ‘Sweetheart’ sweet cherry (Prunus avium L.). Shoots were collected right before chill inception, and exposed continuously to seven different temperatures in the range of -2°C and 16.8°C for 1320 hours. Chilling requirements were determined on sequential field samples from plots of days to bud break against sampling date. Temperature-response curves, which were best fit in a four parameter logistic nonlinear regression, indicated that optimum chilling temperatures were between -2°C and 5.5°C for ‘Gala’ and between -2°C and 7°C for ‘Sweetheart’, with no chilling effect above 13°C in both species. The derived chill unit models predicted that chill unit accumulations required for dormancy completion averaged 921 for ‘Gala’and 740 for ‘Sweetheart’ over the three year period. The year-to-year variation in ‘Gala’ apple was smaller with our ‘Gala’ model than with the ‘Utah’ model (14% vs 23.5% coefficients of variation), while similar to each other in ‘Sweetheart’ sweet cherry.

Dormancy Release and Flowering of Paeonia lactiflora ‘Taebaek’ by Natural Cumulative Chilling and GA3 Treatment

여수미,이용하,이승연,정현환,김기선 한국원예학회 2012 Horticulture, Environment, and Biotechnology Vol.53 No.4

Dormancy breaking and flowering of Paeonia lactiflora ‘Taebaek’ were controlled by natural cumulative chilling and GA3 treatments according to the transfer date in the central region of Suwon, Korea. Shoot emergence and flowering did not occur throughout the experimental period when dormant rootstocks were transferred to a glasshouse between September 10 and October 29, in which the natural cumulative chill (NCU) unit was nearly 0 h. The number of days from the transfer date to sprouting and flowering was shortened as the transfer date was delayed. All the plants flowered normally with shoot growth when they were transferred after December 31 (1,222 h NCU). All dormant buds that were treated with GA3 sprouted, regardless of transfer date, but failed to flower due to shoot blasting and flower bud abortion when they were transferred between September 10 (0 h NCU) and November 12 (185 h NCU). Shoot blasting was 38% when they were transferred on November 26 (429 h NCU). When GA3 was applied to the plants after December 17 (876 h NCU), they flowered without blasting. Plant height and stem diameter were not affected by GA3 treatment. GA3 treatment decreased the number of days to sprouting and flowering, and increased the number of flowers, irrespective of insufficient chilling accumulation, as compared to 1,222 h NCU on December 31. According to the above results, at least 1,222 h NCU could be recommended as a practical forcing method for dormancy release, subsequent growth, and normal flowering of dormant P. lactiflora ‘Taebaek’ in a temperate climate region. The GA3 treatment played an important role in breaking dormancy and significantly increased the percentage of sprouting, accelerated the days to sprouting and promoted the flowering of P. lactiflora ‘Taebaek’ when the plants had undergone insufficient chilling accumulation.