• Proceedings of the Korean Society of Applied Entomolohy Conference
• /
• 2000.05a
• /
• pp.43-43
• /
• 2000

• Journal of Korean Society of Forest Science
• /
• v.28 no.1
• /
• pp.31-35
• /
• 1975

The present study explored the rapid effect of low temperature on the freezing resistance of dehardening twigs of three apple cultivars and sweet cherry. The effect of low temperature was depending upon the thawing treatment following to the low temperature treatment. When the freezing temperature to $-9^{\circ}C$ for three hours followed by thawing treatment ($5^{\circ}C$) was given repeatedly twice, the low temperature increased apparently the cold hardiness of apple and cherry by 3 to $9^{\circ}C$. On the other hand, when the freezing temperature ($-9^{\circ}C$) for ten hours was pretreated without thawing, the low temperature appeared not affecting the cold resistance of the twigs. The role of freezing-thawing temperature cycle in nature was discussed as a signal of environmental stimulus to which dehardening plant may be responding to increase their cold hardiness so as to adapt against the damage of late frost in early spring.

• Horticultural Science & Technology
• /
• v.30 no.6
• /
• pp.626-634
• /
• 2012

There are variations among grapevine genotypes in the levels of tolerance to cold, and cold-hardiness of grapevine has been affected by the change of short-term environment during over-wintering. In this study, the responses of vines to cold in open field and rain-shelter system were investigated to obtain useful information in increasing the tolerance to cold in grape cultivation. Total carbohydrate content of bearing mother branches was higher in the rain-shelter system than in the open field, and lower in the branches of 'Muscat Bailey A' than in 'Campbell Early' and 'Kyoho'. Bud-burst and shoot growth were better in the rain-shelter system than in open field, whereas there is no significant difference among the treatments of net beside vines. There was also low incidence of gray mold in rain shelter system. Stilbene compounds such as t-piceid, resveratrol, piceatannol, c-piceid were accumulated in the cold-treated shoot from vine cuts harvested in rain shelter system. Genes of chalcone isomerase, manganese superoxide dismutase, proline rich protein 2, and temperature induced lipocalin were highly expressed in the cold-treated shoot from vine cuts harvested in rain shelter system. While there was not change of air temperature, but high reduction of wind speed in the rain shelter system compared to open field, and increase in the reduction of wind speed by net treatment. The damage of grapevines by cold in the extreme low temperature could be reduced by keeping them in the rain shelter system with net during winter season.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.2
• /
• pp.167-176
• /
• 1999

Shoot morphological characteristics were affected by plant population densities in alfalfa. Shoots per plant, yield per shoot, yield per plant, and stem diameter increased with decreasing alfalfa population density. Winter survival was maximized at a plant population of $45plants\;m^{-2}$ or less. The grams of TNC per root increased as the stand density decreased. The lowest LT 50 occurred at the lowest stand density ($16plants\;m^{-2}$ having 25 cm plant spacing) and the highest LT 50 was attained at the highest stand density($494plants\;m^{-2}$ having 4.5 cm plant spacing). There were no differences in shoot morphology, winter survival, and cold hardiness in between 'Algonquin'and 'Vernal'. From this study, high stand density of alfalfa ($278plants\;m^{-2}$ or more) appears to be of little advantage compared to low stand density in terms of winter survival and cold hardiness.

• Korean Journal of Plant Resources
• /
• v.37 no.1
• /
• pp.93-99
• /
• 2024

As a result of low temperature exotherm (LTE) measurement targeting the buds of 13 grape cultivars that are recently cultivated or introduced in Korea, 'Shooting Star', 'Muscat Bailey A', 'IFG-6', 'Vanessa Seedless', 'Summer Crispy', 'Shine Muscat', 'Jelly Pop', 'Campbell Early', 'Ruby Seedless', 'My Heart', 'Kyoho', 'Thompson Seedless', and 'Violet King' in order of being resistant to low temperatures. The LTE value was the lowest at -18.9℃ in 'Shooting Star' and the highest at -12.5℃ in 'Violet King'. Through these results, it can be used as basic data to determine whether or not cultivation by region is possible efficiently by comparing data based on 'Campbell Early' and 'Kyoho', which are presented as standard varieties for domestic cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.7 no.1
• /
• pp.123-127
• /
• 1969

The studies were conducted to know the relationship between $\beta$-amlyase activities and hardiness for the germinated seedlings of, winter wheat varieties which were classified with eye estimated cold resistance in field as, susceptible, moderate and resistant. These varieties were tested in continued five days from germination in four replicated split plot design. For the measurement of $\beta$-amylase, improved A. K. Balls method (2) was employed. Result obtained will be summarized as follows. 1. Tested varieties showed highly significant differences in $\beta$-amylase activity, while no differences were obtained between dates after germination. 2. Winter hardy varieties, Yukseung ＃3, Chin Kwang and Suwon＃85 showed higher amylase activities than the moderate hardy varieties, Jukdalma, Kangdosinryuk and Norin ＃4, while lower activities were measured in susceptible varieties, Norin ＃6, Kangdo and Norin＃12. 3. With measurement of $\beta$-amylase activity, rurther detail classification to cold resistance is seemed available than eye-estimating in the field condition. 4. In accordance with testing dates, amylase activities were not so clear on 1st, 2nd, 4th and 5th days from germination, while clear differences were found on 3rd day from germination. 5. Amylase activity obtained on 3rd day after germination is considered easy and effective method to estimate cold resistance of wheat varieties with a classification standard.

• Korean Journal of Environmental Agriculture
• /
• v.33 no.4
• /
• pp.327-333
• /
• 2014

BACKGROUND: Rabbiteye blueberry(Vaccinium ashei) is one of the most widely grown blueberry types in the world, together with Northern and Southern highbush blueberry(Vaccinium corymbosum). Rabbiteye blueberry have higher soil adaptability and fruit productivity but less cold tolerance to low temperature than highbush blueberry. The objective of this study is to investigate freezing tolerance of floral buds and establish a cultivation zone for rabbiteye blueberry cultivars. METHODS AND RESULTS: Bearing branches which have similar thickness and same number of floral buds were collected in the early January at the blueberry germplasm preservation plot located in Namhae Sub-station, National Institute of Horticultural and Herbal Science in Gyeongsangnamdo. Cold response of bearing branches were investigated by electrolyte leakage and freezing tolerance of floral buds were determined by ovary browning ratio of 50%($LT_{50}$). Cultivation zone was established based on mean annual extreme minimum temperature for 30 years, from 1981 to 2010. The electrolyte leakage of bearing branches in rabbiteye blueberry increased as temperature decreased and was lowest in 'Brightwell' but highest in 'Bluegem' when they were kept in $-5^{\circ}C$. Besides, the electrolyte leakage increased in 'Brightblue', 'Brightwell', 'Climax', 'Delite', 'Gardenblue', 'Southland' and 'Woodard' in $-20^{\circ}C$. Freezing tolerance($LT_{50}$) was lowest in 'Bluegem' and 'Homebell'($-13.3^{\circ}C$), and highest in 'Tifblue'($-25^{\circ}C$) among different rabbiteye blueberry cultivars. $LT_{50}$ of 'Southland' was from -15.0 to $-16.7^{\circ}C$, that of 'Delite', 'Brightwell',' Austin' and 'Climax' was $-18.3^{\circ}C$, and that of 'Bluebelle', 'Woodard' and 'Powderblue' was $-20^{\circ}C$. CONCLUSION: This study indicate that The hardiness zones of rabbiteye blueberry were classified into Six cultivation zones and cultivation zones of most cultivars were the south of Jeollanam-do and Gyeongdangnam-do, except for 'Tifblue.'

• Horticultural Science & Technology
• /
• v.18 no.3
• /
• pp.387-390
• /
• 2000

The experiment was conducted to investigate the effects of vine management and yield on fruit quality and bud burst of 'Campbell Early' grapevines in Hwaseong and Suwon area. The extreme value of minimum temperature of Hwaseong area, frequently causing cold damage, was lower than that of Suwon area in winter. Narrow spacing, overbearing, and poor vine management were observed in Hwaseong area, where the harvest time was delayed by 7 days compared with that of Suwon area. Total carbohydrate content of bearing mother branches was lower with 1.2~1.7%, and the percentage of bud burst was extremely lower at $-15^{\circ}C$. In Suwon area, there were no differences in cluster and berry size, but soluble solids content was lower and skin coloration was poorer when yield was high. Total carbohydrate content was lower when yield was high. The percentage of bud burst was lower at cold treatments below $-20^{\circ}C$. The results suggest that appropriate yield based on fruit quality is 2.3~2.6 MT/10a.

• Journal of Sericultural and Entomological Science
• /
• v.44 no.2
• /
• pp.56-58
• /
• 2002

An autotetraploid, Sawonppong 28 was derived from a thick-leaf and highly productive mulberry variety, Huyeoprok, by colchicine solution treatment on growing point and its characteristics were as follows. The number of somatic chromosomes of the derived variety was 2n=56 of an autotetraploid and green tip sprouting stage was medium budding variety with triangular oval shape and thick leaves contained rich chlorophyll. The length of branches was comparatively short and the number of branches was also small. However the branches were thick and non-budding length percentage at basal part of branch was high and cold hardiness was weak.

• Journal of Animal Science and Technology
• /
• v.46 no.3
• /
• pp.437-442
• /
• 2004

Forage legumes are being used as an important source of protein for dairy farm as well as nitrogen fertilizer. This experiment was conducted to evaluate forage production and quality of five legumes at Cheonan Yonam College Experimental Livestock Farm for 1 year(2001-2002). Five legumes were crimson clover (Trifolium incarnatum L.) 'Tibbee', hairy vetch(Vicia villosa Roth) 'Common', red clover(Trifolium pratense L.) 'Kenland', persian clover(Trifolium resupinatum L.) 'Leeton', alfalfa(Medicago sativa L.) 'Vernal'. All legumes were shown cold hardiness of 8 rating or higher except crimson clover(7 rating). Flowering stage was observed 23th of April for crimson clover, 13th of May for hairy vetch, 3rd of May for red clover, and 12th of May for alfalfa. But persian clover didn't at harvest. Dry rnatter(DM) of crimson clover(17.6%) was the highest among legumes. In DM and total digestible nutrients(TDN) yields, crimson clover and hairy vetch were higher than those of other legumes. The crude protein of hairy vetch(20.5%) was the highest among legumes. In neutral detergent fiber(NDF) and acid detergent fiber(ADF), persian clover was the lowest(35.0% and 25.0%). Calculations of relative feed value(RFV) based on NDF and ADF of legumes were over 125(Prime degree) except hairy vetch. RFV and TDN of persian clover were the highest among legumes. According to the results of this study, crimson clover and hairy vetch are excellent in forage yield. Persian clover is superior in forage quality among legumes.