• Horticultural Science & Technology
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• v.32 no.1
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• pp.10-17
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• 2014

This study was conducted to elucidate the relationship between light and coloring and to obtain basic results for promoting redness expression in 'Kalle' (Pyrus communis L.) pear skin. It was investigated in location of anthocyanin layer by microscopic observation and differences in skin color expression of 'Kalle' bagged with paper bag which has different light transmittance rate and inside temperature. However, there was no anthocyanin layer in the brown skin and golden yellow color, anthocyanin layer was distributed in epidermins or hyperdermis of red skin pear and apple. Dark red colored 'Kalle' had more anthocyanin content, $29.8mg{\cdot}100g^{-1}$ FW than light red colored apple 'Hongro'. Light transmittance rate of physical characteristics used paper bags was the highest in white paper bag, 42.2% and it also had more light quantity, $8.9{\mu}mol$ than any other tested paper bags in specific wave length 650-655 nm. The maximum temperature of inner bag was higher about $3^{\circ}C$ in yellow paper bag. The red coloration and anthocyanin contents in no bagged fruits were higher than in any other bagged fruit. However, red color expression among the bagged fruits was higher in white paper bag than in double layered black paper bag and yellow paper bag. Also, chromaticity value seemd to be a good index to explain variation of fruit skin color, because anthocyanin content and chromaticity value were higher. Based on these results, it is desirable to cultivate 'Kalle' without bag for stable redness expression but bagging is essential for decreasing damage by insect in Korea. Further examination to find suitable time of removing paperbag for redness expression and decreasing insect damage. In addition, it is required to develop paperbag whose transmittance rate is high in specific light wavelength or temperature of inner bags is low. Additional key words: anthocyanin, bagging, chromaticity value, light transmittance, Pyrus communis L.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.126-133
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• 2019

In recent years, the deterioration of fruit quality caused by poor coloration and sunburn disorder has become serious problems in apple market, which is a result of the increase of surface temperature due to the abnormal temperature increase during summer season. This study was conducted to investigate the effect of wind net shading and fine water spray using sprinkler on fruit coloration, sunburn damage and overall fruit quality of 'Fuji' and 'Hongro' apples. Fifteen sprinklers (7L/hr) were installed at the orchard of the Chungcheongnam-do Agricultural Research and Extension Services, located in Sinam-myeon Chungcheongnam-do Korea, at a height of 3m above the apple tree of $1.5m{\times}3.5m$ north-south direction. Fine water spraying treatment was divided into day time spray (10:00 am to 6:00 pm) and all day spray (10:00 am to 10:00 pm) from early July to 10 days before harvest in 2017 and 2018 season, respectively. Temperature of the surface of apple fruit, characteristic of fruit, and degree of sunburn damage were investigated. In 'Fuji', the fruit surface temperature checked at 2 pm on August 10 was decreased considerably in the day time spray ($35.6^{\circ}C$) and wind net ($39.0^{\circ}C$) when compared with the untreated control ($44.4^{\circ}C$). Similarly, the fruit surface temperature also decreased considerably in the all day spray ($35.1^{\circ}C$) and wind net ($36.9^{\circ}C$) treatments when compared with the untreated control ($46.5^{\circ}C$) in 'Hongro' apples. The incidence of sunburn disorder was significantly decreased with day time spray (5.0%), all day spray (5.8%) and wind net (7.0%) when compared with untreated control (23.4%) in 'Fuji' apples. As a results, the treatment of fine water spray and wind net consequently showed 26% and 34% increase of redness ($a^*$) value in the skin color difference, respectively, in 'Fuji' apples.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.954-958
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• 2010

The study was conducted to investigate the relationship between berry set density per bearing shoot and fruit quality in 'Kyoho' grape. Fruit quality was evaluated by soluble solids content (SSC), titratable acidity (TA), skin color, and total anthocyanin content (TAC). There was a sharp increase in SSC of fruit juice from veraison initiation to 30 days after veraison. The SSC level increased with the lower berry set per bearing shoot. The rapid accumulation of SSC 4 weeks after veraison in the cluster of low berry set (10-20) was observed, while that of high berry set (40-50) showed delayed and low SSC accumulation which reached only $15.0^{\circ}Bx$ at harvest. TA of fruit juice in all treatments reduced rapidly from veraison initiation to 30 days after veraison, and then reduced gradually. TA in all treatments except 50 berries set reached to 0.4-0.6% which was optimal TA in 'Kyoho' at fruit harvest. During fruit maturing after veraison, fruit skin color changed from green to purple-black, L and b value decreased, and a value increased. TAC in 10 and 20 berries set was gradually increased to 2 weeks after veraison, sharply increased until 6 weeks after veraison, and then finally decreased, while TAC in content in 30, 40, and 50 berries set per annual shoot remained at low level. The results indicated that the number of berry set for good quality seemed to be 20 per bearing shoot in 'Kyoho' grape.

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

• Horticultural Science & Technology
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• v.31 no.6
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• pp.732-739
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• 2013

'Akihime' plums picked at mature stage (50-70% red coloration of the fruit skin) were stored at $1^{\circ}C$ under air or controlled atmosphere (CA) storage regime as following 3% $O_2$ + 1, 3, 5, and 7% $CO_2$ for 50 days for the purpose of assessing the effect of CA storage on the maintenance of fruit quality and the reduction of chilling injury. Fruits stored under CA storage regime showed reduced respiration as well as ethylene production rates compared to the fruits stored in air. Quality attributes including weight loss, Hunter 'a' values, soluble solids content, titratable acidity, and firmness showed smallest changes in fruits stored under CA conditions except for 3% $O_2$ + 7% $CO_2$. High incidence of physiological disorders including chilling injury, flesh browning, and decay were found in fruits stored under both air and CA of 3% $O_2$ + 7% $CO_2$. In our study, the CA storage regime of 3% $O_2$ + 5% $CO_2$ was found the most effective for maintaining overall fruit qualities of 'Akihime' plums produced in Korea, also delayed the development of chilling injury including lack of juiciness and flesh browning. From the results, storage at 3% $O_2$ + 5% $CO_2$ was selected as an optimal condition of 'Akihime' plum for extending storage life up to 50 days at $1^{\circ}C$.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.9-15
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• 2016

High temperature is one of the important environmental factors limiting cultivation of apple (Malus domestica Borkh). The expression of genes related with anthocyanin synthesis and sugar accumulation in response to high temperature was studied in the 'Hongro' apple fruits at different developmental stages in different temperature conditions through real-time PCR. Expression of ${\hat{a}}$-amylase (BMY) and polygalacturonase (PG) genes related with sugar synthesis was higher in late ripening stages than in initial ripening stages. Expression of four genes such as phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), flavanone 3-hydroxylase (F3H), and malate dehydrogenase (MDH), which were related with fruit skin coloration, increased gradually in apple fruits of the middle and late ripening stages. Interestingly, the expressions of all genes were highly inhibited expressed at $30-35^{\circ}C$ compared to $25^{\circ}C$ in all ripening stages. In the further work, investigation of expression levels of various genes could be conducted in the level of transcriptomics in fruits at the middle ripening stages to get meaningful information of ripening metabolism in apple in high temperatures.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.170-177
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• 2017

This study was conducted to estimate the light pollution damage caused by night-break lighting in 'Kyoho' grapes. Night irradiation was performed every night for four hours (10 p.m. to 2 a.m.) from the full bloom to the harvest stage using red, blue, and white lamps as artificial light. Fruit yield, soluble solid content, anthocyanin content, and chlorophyll a content were affected by night irradiation. The soluble solid content of the control was $17.5^{\circ}Brix$, approximately $1^{\circ}Brix$ higher than the red ($16.4^{\circ}Brix$), blue ($16.2^{\circ}Brix$), and white light treated grapes ($16.3^{\circ}Brix$). The anthocyanin content of the skin was also higher in the control at $4.08{\mu}g{\cdot}cm^{-2}$ compared to the red ($3.14{\mu}g{\cdot}cm^{-2}$), blue ($2.47{\mu}g{\cdot}cm^{-2}$), and white ($2.82{\mu}g{\cdot}cm^{-2}$) light treated samples. On the other hand, the chlorophyll a content of the control was the lowest at $0.268{\mu}g{\cdot}cm^{-2}$ as compared with the red ($0.339{\mu}g{\cdot}cm^{-2}$), blue ($0.345{\mu}g{\cdot}cm^{-2}$), and white ($0.372{\mu}g{\cdot}cm^{-2}$) light treated samples. Considering that higher soluble solid contents, higher accumulation of anthocyanin, and lower chlorophyll a contents are factors involved in fruit maturation, night irradiation may delay fruit maturation and red light treatment may result in decreased yield. Our results confirmed that night-break lighting regardless of the wavelength provoked light pollution in 'Kyoho' grapes. Therefore, fruit maturation may be poor in the presence of artificial light, including streetlamps, in neighboring vineyards.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.1
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• pp.53-57
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• 2013

A severe defoliation by typhoon in early autumn reduces fruit quality for the current season and reserve accumulations for the next season. This study was conducted to determine the effects of foliar applications during the autumn on alleviating the damages after defoliation. Leaves of 2-year-old 'Fuyu' trees, grown in 50-L pots under a rain-shelter, were 75%-defoliated on September 9. In mid-September and early October, trees were treated either with eight foliar applications of urea or with four alternating applications of urea and $KH_2PO_4$ (urea + KP application), all at 0.5% (w/v). Trees untreated after the defoliation served as the control. The urea applications slightly increased N and P concentrations of the leaves collected on November 6, while urea + KP applications significantly increased P and K concentrations. Foliar applications did not affect fruit growth, but tended to decrease skin coloration. Fruit soluble solids increased by 1.5 and $1.0^{\circ}Brix$ for urea and urea + KP applications, respectively. There was a significant increase in dry weight of fine root for the foliar application treatments but not in those of aerial woods and larger roots. With the foliar applications, N concentration tended to increase in the permanent organs but not P and K, whereas soluble sugars and starch notably increased in shoot, trunk, or fine root regardless of the different applications. Results indicated that the foliar applications could partially help to restore fruit quality and carbohydrate accumulations in the defoliated trees.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.55-60
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• 2013

BACKGROUND: The buds of persimmon trees are susceptible to cold damage, often with the late frost, at the time of budburst. This study was conducted to determine effect of the cold damage on shoot and fruit growth the current season. METHODS AND RESULTS: 'Fuyu' trees, grown in 50-L pots, were placed for 1 h at $-2.2{\pm}0.5$, $-2.6{\pm}0.5$, or $-3.0{\pm}0.5^{\circ}C$ within a cold storage, at their budburst on April 5. Some trees under ambient temperature at $10-17^{\circ}C$ served as the control. Cold damage of the buds containing flower buds was 54% at $-2.2^{\circ}C$, and significantly increased to 95% at $-3.0^{\circ}C$. The bud damage included the complete death of all, complete death of main buds only, or the late and deformed shoot growth in the spring. Number of flower buds in early May dramatically decreased as the damage ratio increased. Since the thinning of flower buds in mid-May and fruitlets in early July was done in no or slightly damaged trees, the final number of fruits and yield did not decrease compared with the control when the damage increased by 60% and 70%, respectively. Average fruit weight and skin coloration tended to be better with increasing bud damage. Shoot growth was more vigorous in those trees whose buds were severely damaged by low temperature. CONCLUSION(S): Shoot growth and the yield may depend on the number of flower buds and percent fruit set after the cold damage.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.1-8
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• 2013

This study was conducted to compare the local climate conditions and growth periods for the apple (Malus domestica 'Borkh') orchards at different altitudes (330, 500, and 670 m) in Jangsu-Gun, Korea. Observation data for the growth period show that the monthly mean air temperatures at the 'Hongro' apple orchard sites decrease with height at the rate of 1.0 to $3.0^{\circ}C$/100 m. The monthly minimum temperatures in April (blooming period for 'Hongro' apple) were 4.3, 2.9, and $0.4^{\circ}C$ at 330, 500, and 670 m, respectively. The monthly mean temperatures in September (i.e., the coloration and maturation period) were 20.6, 18.7, and $14.5^{\circ}C$, respectively. The annual precipitation range varied from 1,234 to 1,439 mm, which tended to increase with height. The heavy rainfall occurred in summer (June to August) and amounted to 827-933 mm. No significant differences in the duration of sunshine were observed amongst the orchards at three different altitudes. The earliest bud break was observed at the 330 m altitude (18 March 2009), which was 4 and 11 days earlier in comparison to those at 500 and 670 m, respectively. The time of full bloom at 330 m was 12 days ahead of that at 670 m. The optimal maturation of fruit (based on skin redness > 80%) was observed between 7 and 10 September at 330 m, 15 and 18 September at 500 m, and 21 and 23 September at 670 m.