• Mycobiology
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• v.44 no.4
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• pp.319-324
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• 2016

Dieback in strawberry (Seolhyang cultivar) was first observed during the nursery season (June to September) in the Nonsan area of Korea in the years 2012 and 2013. Initial disease symptoms included dieback on runners, as well as black rot on roots, followed by wilting and eventually blackened, necrotic discoloration in the crowns of daughter plants. A fungus isolated from the diseased roots, runners, and crowns is close to Lasiodiplodia theobromae based on morphological characteristics. Analysis of a combined dataset assembled from sequences of the internal transcribed spacer and translation elongation factor 1- alpha genes grouped nine fungal isolates with the type strain of L. theobromae. The isolates showed strong pathogenicity on strawberry cultivars Kumhyang, Seolhyang, and Akihimae, fulfilling Koch's postulates. Based on these results, the pathogen responsible for dieback on strawberry plants in Korea was identified as L. theobromae.

• Journal of Microbiology and Biotechnology
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• v.32 no.7
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• pp.862-868
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• 2022

Microalgae are photosynthetic cyanobacteria and eukaryotic microorganisms, mainly living in the water. In agriculture, numerous studies have been conducted to utilize microalgae as a biostimulant resource. Scenedesmus has been known to be one such microalga that can promote plant growth by secretion of auxin or cytokinin hormone analogs. However, no research has been performed on the effect of microalgae treatment on plant microbiota communities. This study was conducted to investigate the mode of action of microalgae as biostimulants in a plant microbiota perspective by using Scenedesmus sp. CHK0059 (also known as species Chlorella fusca), which has been well documented as a biostimulant for strawberries. The strawberry cultivar Keumsil was bred with Seolhyang and Maehyang as the parent cultivars. Using these three cultivars, microbiota communities were evaluated for changes in structural composition according to the CHK0059 treatment. CHK0059-treated Seolhyang, and CHK0059-untreated Maehyang were similar in microbial diversity in the endosphere. From a microbiota community perspective, the diversity change showed that CHK0059 was affected by the characteristics of the host. Conversely, when CHK0059 treatment was applied, populations of Streptomyces and Actinospica were observed in the crown endosphere.

• Food Science and Preservation
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• v.23 no.1
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• pp.12-19
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• 2016

This study was conducted to determine $CO_2$ treatment condition to extend the shelf-life of 'Seolhyang' strawberry. Fresh strawberries with red color on 80% of the fruit surface were harvested. The samples at two different stages (on the $1^{st}$ and $3^{rd}$ day after harvest) were placed in a gas-tight chamber with 0, 5, 15, or 30% $CO_2$ concentration for 3 hours at $4^{\circ}C$. Then, the strawberry samples were immediately packaged in a PET tray and stored at $4^{\circ}C$. The carbon dioxide treatment was effective in maintaining the quality of 'Seolhyang' strawberries treated on the $1^{st}$ day after harvest. These samples had higher firmness, lower redness, softening index, and decay rate compared to samples treated on the $3^{rd}$ day after harvest. Treatment with both 15 and 30% of $CO_2$ concentration on the $1^{st}$ day after harvest induced an increase of firmness of 'Seolhyang' strawberry after the treatment. Samples treated with 15 and 30% $CO_2$ the $1^{st}$ day after harvest maintained quality for 10 days. However, samples treated with $CO_2$ on the $3^{rd}$ day after harvest lost marketability at 10 days of storage. At the atmosphere containing 30% $CO_2$ on the $1^{st}$ day after harvest was most effective in reducing decay rate and fruit softening, and maintaining bright red color of strawberries among different $CO_2$ concentrations. Therefore, a 30% $CO_2$ treatment within one day after harvest can be a practical postharvest technology to extend shelf-life of 'Seolhyang' strawberry.

• Journal of Sericultural and Entomological Science
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• v.52 no.2
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• pp.134-141
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• 2014

This study was examined the pollinating activity and the economical effect according to numbers released of Apis mellifera in the $825m^2$ strawberry (Seolhyang var.) vinyl-houses. The time-zone of pollinating activity relative to numbers of honeycomb released at the strawberry (Seolhyang var.) vinyl-houses was together from 9A.M. to 4P.M., and the peak time of pollinating activity was 11A.M.. The effects on pollinating activity relative to the honeycomb numbers in the honeybee hive released at the strawberry houses were ordered 5 honeycombs (11,000 heads), 4 honeycombs (8,800 heads) and 3 honeycombs (6,600 heads). The rate of workers lost in A. mellifera hives with 5 honeybee combs and 4 honeycombs during the strawberry cultivating period were lower than that of 3 honeycombs. The rates of fruit set by pollinating activity relative to the honeycomb numbers in the honeybee hive released at the strawberry vinyl-houses were same level with over 98%. The fruit qualities; No. of seeds, sugar content and rate of normal fruit set were same level, but fruit weights were ordered 5 honeycombs in 37.2 g, 4 honeycombs in 35.6 g and 3 honeycombs in 32.6 g. The marketing incomes of 4 honeycombs and 5 honeycombs were 9% to 13% higher than that of 3 honeycombs, respectively. Therefore, when the strawberry (Seolhyang var.) was planted at $825m^2$ of a vinyl-houses, it was surveyed that the most suitable numbers of honeycomb were over 4 honeycombs (8,800 heads).

• Horticultural Science & Technology
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• v.28 no.4
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• pp.540-544
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• 2010

The nursery plant quality and flower bud induction of new strawberry cultivars, 'Maehyang' and 'Seolhyang' in forcing culture were evaluated in the highland and lowland region. In order to produce daughter plants, the new cultivars were grown in the open field located at both highland (Daekwallyung, above 800 m sea level) and lowland (Gangneung, above 20 m sea level) region, respectively. The average air temperature at highland during nursery plant propagation period was $5.3^{\circ}C$ lower than those at lowland. The number of daughter plants produced at lowland was 2 times as high as those of highland, presumably due to the higher air temperature. Anthracnose incidence rates of runner plants produced at lowland were 4 to 7% as high as those in highland. Mean temperature in the highland ($23.5^{\circ}C$) during flower bud differentiation treatment was $5.1^{\circ}C$ lower than that in the lowland ($28.6^{\circ}C$). Seedlings produced in highland showed higher C/N ratio and lower T/R ratio compared to those produced in lowland. The average flower bud formation date of the daughter plants grown in highland were advanced by 30 days compared to the date in lowland. Accordingly, highland was supposed to be appropriate region for raising seedlings in forcing culture of the new strawberry cultivars of 'Maehyang' and 'Seolhyang'.

• Horticultural Science & Technology
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• v.30 no.2
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• pp.144-151
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• 2012

Diagnosis of nutrient disorders in cultivating crops is based on the visual symptoms and results of soil and plant analysis. This study was carried out to investigate the influence of B concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. Tissue analysis based on the dry weight were also conducted to determine the threshold levels in plants when toxicity developed in boron. The growth was seriously restricted in the three strawberry cultivars as the B concentrations in fertilizer solution were elevated. The fresh and dry weights were heavier and crown diameters were thicker in the 0.25 mM boron treatment than the other treatments tested. The toxicity symptoms of boron appeared on the older leaves of three strawberry cultivars while interveinal chlorosis symptoms appeared on the young leaves of 'Keumhyang' and 'Seolhyang' strawberries. The toxicity symptoms in lower leaves were developed when B concentrations in fertilizer solution were higher than 2 mM in 'Keumhyang' and 0.5 mM in 'Maehyang' and 'Seolhyang' strawberries. The elevated boron concentrations in fertilizer solution did not influence the tissue K, Ca, and Mg contents, but influenced the phosphorus contents with decreasing tendency. The tissue Fe and Zn contents decreased and increased, respectively, as the B concentrations in fertilizer solution were elevated. When the concentration of boron at which the growth of a plant is retarded by 10% is regarded as a upper threshold level, the boron contents based on dry weight of above ground plant tissue should be lower than 25.1, 44.2, and 62.5 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang', and 'Seolhyang' strawberries, respectively.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.49-55
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• 2017

The objective of this research was to investigate the effects of planting date, root pruning and uprooting on growth, yield and budding ratio of 'Seolhyang' strawberry (Fragaria${\times}$ananassa Duch.). Planting dates of plantlets with 60 ~ 70 days old were September 7th, September 14th and September 21th. Root pruning rates were controlled to 25% (RP 25) or 50% (RP 50) before transplanting. In the uprooting treatments, the plantlets were pulled out on root media and were replanted into same bed at 10 days (UR 10) and 20 days (UR 20) after transplanting. The delayed planting dates of plantlet resulted in the suppressed growth of plant, reduced yield, and slight earlier appearance of flower buds. The RP 50 treatment showed the lowest value among root pruning treatments in growth and yield, but appearance of flower buds slightly fall behinds. The UR 20 treatment only made flower budding earlier by 6 days than non-treatment. All of root stress treatment was appeared to decrease vegetative growth and yield except the RP 25 treatment. Above results imply that strong root stress was required to emerge second flower bud earlier but which reduced overall growth and yield in 'Seolhyang' strawberry.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.726-731
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• 2013

Experiments were conducted to evaluate the effect of low temperature-darkness treatment on floral initiation in four kinds of Korean strawberry cultivars. Mother plants were planted on March 29 and daughter plants were raised for the experiment. Temperature treatment was done for 7, 14, and 21 days keeping $13^{\circ}C$ in cooling storage from August 29, September 5 and September 14 to September 21. After the treatment, flower bud initiation was examined by a microscope, and the seedlings were transplanted on hydroponic system with Yamazaki's strawberry solution of EC $0.8dS{\cdot}m^{-1}$ to check the flowering. 'Ssanta' and 'Maehyang' showed early flower bud initiation in 7 days treatment than 'Seolhyang' by microscope check. 'Ssanta', 'Daewang', and 'Maehyang' showed early flower bud initiation in 14 days treatment than 'Seolhyang'. There were no differences among the treatments in 21 days treatment. Percentage of flowering of 'Seolhyang' and 'Maehyang' by low temperature-darkness treatment didn't show any difference but 'Daewang' and 'Ssanta' showed high percentage of flowering. It suggested that low temperature-darkness treatment technique can be use for improving early flowering and yield of 'Ssanta' and 'Daewang' cultivars.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.948-953
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• 2010

We evaluated the bioactive compounds including carbohydrates (CH), organic acids (OA), ascorbic acid (AA), anthocyanin (AC), and ellagic acid (EA) in the achenes, epidermis, and flesh of fully ripe strawberry fruits of the 'Maehyang', 'Seolhyang', 'Keumhyang', 'Akiheme', and 'Red pearl' cultivars. The total contents of CH, OA, AA, and AC were significantly greater in the epidermis than in other tissues, while the EA content was significantly greater in the achenes than in other tissues. The AA content of the epidermis ranged from $49.1-69.2mg{\cdot}100g^{-1}$ FW and was significantly greater than the content of the flesh, while AA was not detected in the achenes of any of the tested strawberry cultivars. The AA contents of the epidermis and flesh of the 'Maehyang' were 69.2 and $42.2mg{\cdot}100g^{-1}$ FW, respectively, and were greater than those of the other cultivars. The AC contents in the epidermis and achenes of the 'Keumhyang' were $74.0mg{\cdot}100g^{-1}$ FW and $36.7mg{\cdot}100g^{-1}$ DW, respectively, greater than those of the other cultivars. The EA content of the achenes of the 'Seolhyang' was $215.5mg{\cdot}100g^{-1}$ DW, significantly greater than those of the other cultivars. Results indicate that the antioxidant levels and other chemical compounds of strawberry fruits vary significantly among different fruit tissues. Our results also suggest that the recently introduced Korean 'Maehyang', 'Seolhyang', and 'Keumhyang' contain higher levels of antioxidants than other major June-bearing strawberry cultivars. These cultivars are feasible selections for both growers and consumers.

• Horticultural Science & Technology
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• v.28 no.5
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• pp.777-782
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• 2010

This research tested five modified Hoagland solutions for proper fertility management of nitrogen in 'Seolhyang' strawberry cultivations. The changes of nutrient solutions were in total nitrogen concentrations ($meq{\cdot}L^{-1}$) such as 0 (${NO^-}_3$), 2.5 (${NO_3}^-$), 5 (${NO_3}^-$), 10 ($7.5{NO_3}^-$ + $2.5{NH_4}^+$) and 15 ($10{NO_3}^-$ + $5{NH_4}^+$). The fresh weight and $NO_3$-N concentrations in petiole sap responded to the elevated nitrogen concentrations in fertilizer solution in quadratic (y=7.10+2.668x-$0.115x^2$, $R^2=0.7983^{***}$) and linear (y=26.14+5.245x, $R^2=0.6083^{***}$), respectively. The dry weight and N content of the above ground plant tissue responded to the elevated nitrogen in quadratic (y=2.140+0.492x-$0.022x^2$, $R^2=0.6110^{***}$) and linear (y=0.569+0.033x, $R^2=0.6952^{***}$), respectively. In our experiment the solution with $5meq{\cdot}L^{-1}$ of ${NO_3}^-$ showed positive results in both dry and fresh weight productions. However, a future research about modification of this solution and growth and nutrient uptake response is necessary to achieve better growth of 'Seolhyang' strawberry.