• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.185-190
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• 2018

This study was conducted to investigate the optimum electrical conductivity (EC) levels of nutrient solution for growth of mother plants and increasing occurrence of daughter plants of strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) using hydroponics. The mother plants of strawberry were transplanted in cultivation pot ($61{\times}27{\times}18cm$) filled with coir medium on March 22, 2017. Nutrient solution was supplied by the drip tape at $0.6dS{\cdot}m^{-1}$ of EC levels for rooting during 11 days. After rooting, the mother plants of strawberry was treated at the EC levels of 0.6, 1.2 or $1.8dS{\cdot}m^{-1}$, respectively. Growth characteristics, such as mother plants and daughter plants of strawberry were measured at 100 days after transplanting. The plant height of mother plant was significantly higher at $0.6dS{\cdot}m^{-1}$ treatment, and the crown diameter of mother plant was significantly greater at $1.8dS{\cdot}m^{-1}$ treatment. The fresh and dry weights of shoot were higher at both 0.6 and, $1.2dS{\cdot}m^{-1}$ treatments. The number of runners was not significantly different in all treatments. The fresh and dry weights of runner were heavier at $0.6dS{\cdot}m^{-1}$ than other treatments. The number of daughter plants was the highest, 16.7 at the $1.2dS{\cdot}m^{-1}$ treatment. However, the fresh and dry weights of third daughter plant were the heaviest at $0.6dS{\cdot}m^{-1}$ treatment. Although the daughter plants were a large of production at $1.2dS{\cdot}m^{-1}$ treatment, the low EC levels of strawberry were positive in terms of seedling quality during nursery. These results indicated that growth of mother plant and occurrence of daughter plants were greater at the EC $0.6dS{\cdot}m^{-1}$ nutrient solution for hydroponic cultivation of 'Maehyang' strawberry during nursery period.

• Journal of Bio-Environment Control
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• v.24 no.1
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• pp.8-12
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• 2015

There are various limiting factors that take part in the production of daughter plants, but the important thing for mother plants of strawberries is to undergo a sufficient period of dormancy during winter. It is a well known fact that many runners and daughter plants are generated from mother plants that have been through sufficient cold treatment, but such researches were not found in Korea. This experiment was conducted due to the recent need for a research on the effects of cold treatment using 'Seolhyang,' 'Maehyang' and 'Ssanta' cultivars bred in Korea for two years in 2012 and 2013. The strawberries were divided into 4 types treatments: cold treatment plants in which 1,000 hours have passed in the temperature of $5^{\circ}C$ and below; cold+heated treatment plants in which 1,000 hours have passed in the temperature of $5^{\circ}C$ and below, and then 2 weeks in the greenhouse; greenhouse treatment plants raised in the greenhouse; and plants in harvest treatment. The results of the 2012 experiment showed that 'Seolhyang' had the bigger number of daughter plants in the cold, cold+heated, and harvest than greenhouse. 'Maehyang' had the biggest number of daughter plants in the cold+heated, and lowest in the greenhouse and harvest. 'Ssanta' had no significant difference in all treatments. The results of the 2013 experiment showed that 'Seolhyang' and 'Maehyang' both had more daughter plants in cold and cold+heated than in the greenhouse and harvest. 'Ssanta' tended to show a similar result and cold+heated had statistically more daughter plants than greenhouse.

• Journal of agriculture & life science
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• v.53 no.4
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• pp.19-28
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• 2019

This study was conducted to investigate the effect of nutrient solution strength and duration of nutrient starvation on the growth and development of strawberry (Fragaria x ananassa Duch.) 'Maehyang' and 'Sulhyang' at the flowering stage. Cuttings of runner plants were stuck on November 23th, 2017 and were covered with a layer of black plastic film to block light from penetrating and keep the relative humidity high. The black plastic film was removed after 16 days and rooted plants were cultivated for one month with irrigation of water. The Yamazaki nutrient solution with an electrical conductivity (EC) of 1.85 or 3.71 dS·m-1 (1x or 2x ionic strength, respectively) and pH 5.55 was fed to plants after either 0 (control), 1, 3 or 5 weeks of nutrient starvation to the end of experiment. Plant height in both cultivars decreased gradually with the increase in duration of nutritional starvation. The earlier the nutritional starvation started, the smaller the shoot fresh weight of 'Maehyang'. Hence the greatest shoot fresh weight was obtained in the control which was supplied with the nutrient solution continuously. Shoot fresh weight of 'Sulhyang' was the greatest in 1x ionic strength and one week of nutrient starvation before planting. Although number of flowers on the first flower cluster of 'Maehyang' and 'Sulhyang' showed no significant differences, 'Maehyang' had the greatest number of flowers in the 2x ionic strength solution and one week of nutrient starvation before planting, while 'Sulhyang' had that in the 1x ionic strength treatment. These results suggest that it is considered effective to supply a nutrient solution at a low concentration for a short period of time for increasing the number of flower differentiated on the first flower cluster in both cultivars.

• Journal of Bio-Environment Control
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• v.27 no.2
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• pp.103-110
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• 2018

This study was conducted to investigate the optimum irrigation method for propagation of cutting strawberry ($Fragaria{\times}ananassa$ Duch. cv. Maehyang) plantlet in summer season. The cutting strawberry plantlets were planted in 24-cell tray ($60{\times}34{\times}10cm$) filled with commercial mixed medium (Tosilee) and placed in semi closed-type small plastic tunnel. Each semi closed-type small plastic tunnel was treated as follows; control (non-treatment), over head irrigation (twice a day), capillary mats irrigation (twice a day), or fog irrigation (30 minutes turn on and 10 minutes off from 8:00 to 18:00). The strawberry plantlets were rooted during 8 days in the semi closed-type small plastic tunnel, and then plastic film was removed. Growth parameters, such as plant height, root length, number of primary roots, petiole length, leaf length, leaf width, crown diameter, SPAD, leaf area, fresh and dry weights of the shoot and root, were measured at 61 days after cutting. Relative humidity in tunnel was high in the order by fog irrigation, over head irrigation, capillary mats, and the control as 72.5, 56.3, 45.8, and 29% on average, respectively. However, the air temperature was similar in all treatments. On the 4 and 8 days, the rooting rate of strawberry plantlet was significantly higher in the over head irrigation and fog irrigation treatments. Plant height, petiole length, crown diameter, and leaf area were highest in the over head irrigation and fog irrigation treatments. In addition, fresh and dry weights of shoot were greater in over head irrigation and fog irrigation treatments than the others. Dry weight of root was differed significantly heaviest in the fog irrigation treatment. However, root length, no. of primary roots, SPAD value, and fresh weight of root were not significantly different in all treatments. These results indicated that growth and rooting for propagation of cutting strawberry plantlet 'Maehyang' were best achievement in the over head irrigation and fog irrigation treatments.

• Journal of Life Science
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• v.18 no.2
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• pp.234-240
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• 2008

Anthocyanin synthesis in strawberry (Fragaria x ananassa cv Maehyang) begins approximately 26 days postflowering and continued throughout fruit ripening. A set of cDNA clones encoding the anthocyanin biosynthetic enzymes were isolated from strawberry. A pair of primers were designed for polymerase chain reaction (PCR) through the comparison of the nucleotide sequences of homologous genes from diverse plants. Reverse transcriptase-PCRs were performed using cDNA synthesized from ripe fruit total RNA and the primers corresponding to each gene. Eight genes of the anthocyanin pathway were cloned and confirmed by sequencing to code for phenylalanine ammonia lyase (PAL), 4-cummarate CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidine synthase (ANS), UDP-glucose:flavonoid-3-O-glucosyl-transferase (UFGT). Northern analyses showed that the corresponding genes were differentially expressed during the fruit development process. All genes except PAL were predominantly expressed in fruit. Expression of PAL, DFR and ANS was detected 10 days postflowering at the early stage of fruit development, declined for a while and sharply increased 22 days postflowering then showed a peak 34 days postflowering. The other genes, however, were not expressed up to 22 or 30 days postflowering when the initial fruit ripening events occur at the time of initiation of anthocyanin accumulation. The onset of anthocyanin synthesis in ripening strawberry coincides with a coordinated induction of the anthocyanin pathway genes, suggesting the involvement of regulatory genes. We propose that at least two different regulatory mechanisms playa role in the biosynthesis of anthocyanin during color development of strawberry.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.477-483
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• 2012

This study was carried out to investigate the influence of copper concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. The characterization of toxicity symptoms as well as tissue analyses based on dry weight of above ground tissue were also conducted to determine the threshold levels in plants when toxicity developed in copper. The dry weights of the above ground tissue were not significantly different among the treatments of 0.25 mM to 1.0 mM in 'Keumhyang' and 'Maehyang' strawberries and that of 0.25 mM to 3.0 mM in 'Seolhyang' strawberry. This indicates that the 'Seolhyang' strawberry is more tolerant to copper toxicity than 'Keumhyang' or 'Maehyang' strawberries. Application of copper at high concentrations resulted in severe toxicity such as death of extensive areas of leaves. The lower leaves became yellow and die rapidly as the symptoms spread up the plants. The leaf blades and petioles died back to the crown and hang on by mechanical attachment. Symptoms of copper toxicity in lower leaves developed as browning on leaf margins and in patches between leaf veins that became necrotic. The elevation of copper concentrations in fertilizer solution did not influence the tissue phosphorus, potassium, calcium, and magnesium contents based on the dry weight of the above ground tissue. The tissue copper contents increased lineally as the copper concentrations in fertilizer solution were elevated. But the tissue iron, manganese and boron contents were not influenced by the concentrations. When the concentration of copper at which growth of a plant is retarded by 10% is regarded as threshold level, the copper contents based on dry weight of above ground plant tissue should be lower than 71.4, 57.9 and 74.8 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang' and 'Seolhyang' strawberries, respectively. The symptom characterization and established threshold level in copper toxicity would help growers to prevent the reduction of crop growth and yield in 'Seolhyang' strawberry cultivation.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.227-234
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• 2017

This study aimed to investigate the nutrient solution developed by based on nutrient-water absorption rate of strawberry 'Maehyang' by comparing growth and yield for 8 months with 5 kinds of nutrient solution with different ion composition. Strawberry plants were planted at elevated bed and supplied with five kinds of nutrient solutions (RDA), Yamazaki, PBG, University of Seoul (UOS) and NewUOS from one month onwards. Five types of nutrient solution were supplied to the strawberry plants associated with EC $1.0dS{\cdot}m^{-1}$, pH 6.0, $150{\sim}300mL{\cdot}plant^{-1}$ per day. At 60 days after planting, leaf width and leaf petiole of the strawberry plants showed significant differences among nutrient solution types and photosynthesis was higher in RDA and NewUOS nutrient solution and lower in PBG nutrient solution. The EC of the drainage on vegetative growth stage was $0.7{\sim}0.8dS{\cdot}m^{-1}$, which is lower than the supplied EC level, and to $1.0-1.2dS{\cdot}m^{-1}$, afterwards. The pH of the drainage was higher in Yamzaki solution as 6.2~6.8, while the pH of the UOS nutrient solution was lower in 5.1~5.2. Nitrate content was most absorbed in vegetative growth stage and after flower clusters development. The potassium uptake was highest at the NewUOS followed by UOS and Yamazaki nutrient solution. At six months after -planting fresh weight and dry weight of shoot and root were higher in UOS and NewUOS nutrient solution than other nutrient solutions, and the dry matter ratio was lower at 43.5% in Yamazaki nutrient solution and 30.6% in NewUOS nutrient solution than other solutions. Length, width, weight, and sugar content of the strawberries harvested from December to February were unaffected by treatment, but yield was higher in NewUOS nutrient solution due to increasing fruit number and average weight. From March to May, number of fruit was higher in Yamazaki nutrient solution. In conclusion, there was no difference in the growth of 'Maehyang' when 5 nutrient solutions were grown under hydroponics. But in order to improve the marketability, the NewUOS nutrient solution is appropriate to use from planting to February and it is suitable to use Yamazaki nutrient solution after March when temperature is high and the amount of fruit set per inflorescence.

• Journal of Bio-Environment Control
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• v.29 no.4
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• pp.337-343
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• 2020

This study was carried out to evaluate the yield of cuttings according to the planting and runner releasing times of mother plants in order to raise the cutting seedlings of raising seedling period 75 days or more needed for forcing culture of strawberries to be transplanted into the field around the 15^th of September. Three domestic cultivars of 'Maehyang', 'Jukhyang', and 'Kuemsil' were tested. For experiment 1 to determine the yield of cuttings with the change of transplanting time, the mother plant were planted on February 28, March 20, and April 9 in 20 days intervals, and the cuttings were collected two to three times from June 4 to July 1. Experiment 2 was conducted to investigate the yield of cuttings depending on the runner releasing time, the runners were released in three intervals of 20 days, 40 days, and 60 days after planting the mother plant on March 5, and the cutting were collected once to three times from May 29 to June 26. From the comparisons of cutting yield according to the transplanting time of mother plants, February 28 treatment was more 9~25% and 114~165% for each cultivar than March 20 and April 9, respectively (Experiment 1). The yield of cuttings with releasing time 20 days after planting the mother plants had higher by 60~77% and 104~176% for each cultivar than 40 days and 60 days, respectively (Experiment 2). From these results, in case of propagating the seedlings from cuttings needed for field planting around September 15, early planting around in the latter part of February is the best for cuttings yield. In addition, releasing after the removal of the runners produced from mother plants by 20 days after planting gives an advantage over higher yield of cuttings. Consequently, this study suggest to apply an efficient raising seedling system for labor saving and quality improvement in raising seedlings of three strawberry cultivars in Korea.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.72-77
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• 2017

This study was conducted to examine the effect by application method and concentration of plant growth regulator (PGR) on the growth and runner production of strawberry (Fragaria ${\times}$ ananassa Duch. cv. Maehyang) in a velno-type greenhouse. The seedlings of strawberry were transplanted in pot ($64{\times}27{\times}18cm$) filled with commercial mixed medium (Tosilee) on February 22nd, 2016. The 6-benzylaminopurine (6-BAP) was applied with foliar spray or drench, respectively as 900, 1,200 or $1,500mg{\cdot}L^{-1}$ (50 mL per plant) at 3 weeks after transplanting. Nutrient solution was sufficiently supplied by the drip irrigation as EC $0.65dS{\cdot}m^{-1}$ for rooting during 7 days. After rooting, the 450 mL nutrient solution supplied per pot twice a day (10 min). Plant height and crown diameter of 'Maehyang' mother plant appeared no significantly difference. The other growth characteristics, such as root length, number of primary roots, leaf length, leaf width, leaf area and fresh and dry weights of the shoot or root, were significantly the greatest in the control. And, the SPAD value of strawberry was the highest as 44.2 in the drench with $900mg{\cdot}L^{-1}$. The foiler spray was more effective in runner production than drench, and the number of runners appeared high values at the 900 and $1,500mg{\cdot}L^{-1}$. Whereas, the number of strawberry plantlets was effective in the drench. The results indicate that both growth and the number of runners of strawberry plant were the best achieved by foliar spray application at the $900mg{\cdot}L^{-1}$.

• Journal of Bio-Environment Control
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• v.26 no.2
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• pp.140-145
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• 2017

This study was conducted to find out the effects of $CO_2$ fertilization (1,000ppm) on the quality and storability of 'Maehyang' strawberry fruits. Qualities such as firmness, soluble solid, and acidity of strawberry fruits showed higher numbers in those treated with $CO_2$ fertilization compared to those after harvest. Strawberry fruits were stored at $8^{\circ}C$; MA condition using $20,000cc{\cdot}m^{-2}{\cdot}day^{-1}{\cdot}atm^{-1}$ OTR (oxygen transmission rate) films and conventional condition using unsealed PE box stored for 20 and 10 days, respectively. Fresh weight loss rate was less than 1.0% in MA storage regardless of $CO_2$ fertilization treatment. Concentrations of oxygen, carbon dioxide, and ethylene in OTR films did not show any significant difference between $CO_2$ fertilization treatment and control (nontreatment) during storage. $CO_2$ fertilization treatments maintained higher firmness after storage regardless of storage methods, but soluble solid, acidity, and surface color did not differ among the treatments. Visual quality and off-flavor based on sensory evaluation was the highest in $CO_2$ fertilization treated strawberry and stored at a MA condition, and was the lowest in $CO_2$ fertilization treated strawberry and those stored in a conventional condition, respectively. The fungal incidence rate of strawberry fruits showed less in $CO_2$ fertilization treatment than control during both MA and conventional storage. These results suggest that $CO_2$ fertilization can improve firmness, increase visual quality after harvest and storage at $8^{\circ}C$, and the MA storage method enhances the shelf-life of 'Maehyang' strawberry fruits.