Background : Ginseng is an important agriculture plant in Korea. However, plant yield is reduced by pathogens. Cylindrocarpon destructans and Fusarium solani are responsible for root-rot and replant failure of ginseng in Korea. Because of root rot pathogen, the productivity decreased and repeated cultivation is difficult. Methods and Results : The number of Cylindrocarpon destructans and Fusarium solani in soils can be measured by real-time PCR. This methode makes it possible to select of land for caltivation of ginseng. The specific primers of C. destructans and F. solani were synthesized from β-tubulin region. The equation of the standard curve between the colony forming unit(cfu) and the Ct value in the C. destructans was y (Ct value) = -1.608X (cfu) + 39.325. The equation of the standard curve between the colony forming unit (cfu) and the Ct value in the Fusarium solani was y (Ct value) = -1.608X (cfu) + 39.077. This method makes possible to rapidly exactly measure the number of pathogens in soil. C. destructans, a ginseng root rot fungus, was detected in soil samples of 32 (16%) in soil samples. 35.5% of paddy field, 34.3% of paddy field, 64.1% of field, and 65.6% of paddy field were found in perennial plant. Conclusion : As a result, the major causative agent of ginseng root rot was Cylindrocarpon and the onset density was 102 cfu/g in soil. There was no significant difference in density between fusarium and disease.

Background : This study was conducted to select a optimal combination of LED light sources for stable production of sprout ginseng used as vegetables throughout the year. Methods and Results : The treatments to select the optimum LED light source for the production of functional sprout ginseng were ①Blue40%: Green40%: Red40% (B40 + G12 + R20 umol·m-2S-1), ②B50: G25: R10 (B50 + G8 + R5 umol·m-2S-1), ③B50: G20: R40 (B50 + G6 + R20 umol·m-2S-1), ④B35: G20: R35 (B35 + G6 + R18 umol·m-2S-1), ⑤B20: G0: R40 (B20 + R20 umol·m-2S-1), ⑥control (a general fluorescent lamp for plant cultivation, FL40W, PG, 35.0 umol). The ginseng seedlings used in the test were subject to preconditioning process for one week after the cold treatment at 4℃ for at least three months. The root media were composed of porous artificial soil 40% + peat moss 30% + perlite 20% + Vomito (brand name)10%. We planted 35 seedlings (planting density 5 × 7 ㎝) in a 480 × 380 × 295 ㎜ plastic box. The two liters of water were irrigated per a plastic box when water potential reached -33 kPa using a tensimeter. The cultivation room was maintained at 25℃ with 45% of the relative humidity, and 16 hours of lighting for growing conditions. The growing period was 40 to 60 days after planting. The results were as follows; the treatment of LED B50%: G25%: R10% (B50 + G8 + R5 umol·m-2S-1) increased the diameter of the sprout ginseng by 10.3% (4.95 → 5.46 ㎜), root weight 27.3% (1.1 → 1.4 g), fresh weight 38.9% (1.8 → 2.5 g) in comparison with the control. The contents of ginsenoside such as Re, Rg2, Rc, Rb2, and Rd increased 24.2% (24.8 → 30.8 ㎎/g). Conclusion : The optimal light source for sprout ginseng was LED B50%: G25%: R10% (B50 + G8 + R5 umol·m-2S-1), which increased sprout production by 38.9% in comparison with the control.

Background: This study was carried out to determine the best time for collecting ginseng berries without reducing the ginsenoside- Re content of ginseng roots, which are used as food, medicine, or cosmetic materials. Methods and Results: The test variety of ginseng used in this study was is Chunpung, which was collected from a 4-year-old ginseng field. Ginseng berries were collected at 7, 14, 21, 28, 35, 42, 49, and 56 days after flowering. The number of berry bunches per 1.62㎡ ranged from 43.4 to 61.4, while the weight of berries per 1.62㎡ was the greatest when they were collected 49 days after flowering. The root fresh weight per 1.62㎡ was increased by 0.21 - 1.00 ㎏ compared with that before the test, but root weight gain was decreased as the berry collection time was delayed. Total ginsenoside content of 4-year-old ginseng was the highest when berries were collected 7 days after flowering, while the ginsenoside-Re contents was the highest when collection was done 14 days after flowering. Conclusions: The most suitable period for ginseng berry collection was proposed to be from 14 to 21 days after flowering, as this is when the content of ginsenoside-Re, which is useful as a medicinal or cosmetic material, is still high and the ginseng root has not yet decreased in weight.

Background : Recently, there is a urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. In order to develop ginseng varieties with such traits, systematic breeding program and comprehensive field studies are prerequisite. Methods and Results : ‘Jinwon' seeds were collected in 2003 from the farmer field of Pocheon. Physiological investigation and propagation were conducted from 2008 to 2010. It was given the name 'Eumseong No. 11 through the observed yield trial from 2011 to 2013 and local adaptability was carried out from 2014 to 2017. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. Red leaf and red berry at maturing stage were observed. The time of emergence, flowering and berry maturity of the ‘Jinwon’ were faster than those of ‘Chunpoong’. Stem length of ‘Jinwon’ was longer than that of ‘Chunpoong’, whereas stem diameter was thicker than that of ‘Chunpoong’. Main root length was similar but main root diameter is thicker than that of ‘Chunpoong’. The yield performance of this variety was 576 ㎏/10 a in local adaptability test for two years, which is 9% higher than that of ‘Chunpoong’. ‘Jinwon’ showed strong resistance at high temperatures. Conclusion : Our study demonstrated that ‘Jinwon’ is an ideal variety with heavier root weight and enhanced stress resistance and contribute will enhance biotic/abiotic stress resistance and increase the farmers' income.

Background : This study researches on the microclimate, photosynthesis and growth characteristics for the development of shading materials proper for the wide and inclined ginseng cultivation facility which can respond to climate change and save labor. Methods and Results : The wide shading facilities were installed on the area of 1,000 ㎡ in 2014 and 4 facilities were installed on the test ginseng cultivation area. On Mar. 29, 2017, 2 blue shading nets [with the sun blocking rate of 85% (200 g/㎡) and 90% (220 g/㎡)] were installed each for 4 facilities. On June 26, 2017, the aluminum screen and black shading net (with the sun blocking rate of 40% each) were installed during the period of high temperature (30℃ or higher) for each facility. The maximum light intensity under the shading facility was high with blue shading net 85% and PE black shading net 40%, or blue shading net 85% and aluminum screen 40%, higher than other treatments. They were higher by 4.8 - 7.3%, 5.3 - 7.8% each in July and August. Among the coating materials for reducing the high temperature, the aluminum screen coating had less water leakage in early July, late July, mid-August and late August when the precipitation was more than 100 ㎜. The death of the aerial part of ginseng occurred less until October. The growth of the aerial part of 4-year ginseng was better in blue shading net 85% and PE black shading net 40%, blue shading net 85% and aluminum screen 40% or blue shading net 90% and PE black shading net 40% than in blue shading net 90% and aluminum screen 40% The photosynthesis rate was the highest in June with 3.67 μmol CO2/㎡/s under the blue shading net 90% and aluminum screen 40% and with 3.55 μmol CO2/㎡/s under blue shading net 85% and PE black shading net 40% for K-1. As for the land races ginseng, it was the highest with 3.55 μmol CO2/㎡/s under the blue shading net 85% and PE black shading net 40%. For the growth of the underground part of the 4-year ginseng, the blue shading net 85% + PE black shading net 40% or the blue shading net 85% + aluminum screen 40% was the best with respect to the growth of the ground part of the ginseng such as the length of root, the length of main root, diameter of root and weight of root than other treatment. Conclusion : Best coating materials for the wide shading facilities are the blue shading net 85% and aluminum screen 40%.

Background : The use of the rain shelter facility gets more prevalent in the Ginseng cultivation area these days. This study is designed to establish a technique for the stable cultivation of Ginseng in the rain shelter facilities in high temperature (above 30 ℃) without the damage from high temperature Methods and Results : This study was carried out on 3-year Ginseng roots in 2016 in order to find out how to stably cultivate Ginseng in high temperature without suffering the high temperature damage during the cultivation of Ginseng under rain shelter facilities. The rain shading materials were coated with scattering film (scattering film + black shading net 90%), bluish white double-sided film (shading 85%) and PE film (PE film + black shading net 90%). The damage reduction by high temperature was made to the scattering film and bluish-white double-ended film only. An aluminum screen (shading rate: 40%) was installed when the high temperature (above 30℃) was reached while the isoprene (solution of 2000 times) was sprayed 4 times every 7 days from the full development stage. The light transmittance was 12.6 - 13.4% for the scattering film, 10.5 - 10.8% for the bluish-white double sided film and 7.1% for the PE film in the first coating while it was 7.3% for the scattering film and 7.1% for the bluish-white double-sided film when the aluminum screen was installed in high temperature. The high, average and low values in the relative humidity were higher inside the facility than in the outside during the survey period. The area of leaf was the largest under the scattering film. The area of leaf was the largest for the scattered film under the aluminum shade of 40% shading followed by that of spraying of isoprene 4 times, and that of the no-treatment. As for the growth under ground, the growth of underground shoots increased by 40% in aluminum screen, 53.7% in shading and 26.1% in the spraying of isoprene 4 times than non-shading while there was no difference among other rain shelter materials. Conclusion : The result of the research showed that when the scattering film is selected as the rain shelter material film for the cultivation of Ginseng, it is necessary to shade the sunlight as much as 40% by using the aluminum screen or the shading net to reduce the high temperature damage.

Background : The study is designed to establish the standard of wide-shading facilities for the energy-saving and labor-free system in response to the shortage of manpower in rural areas by introducing North American style Ginseng cultivation facility. Methods and Results : This study was carried out at the Income & Resources Research Institute, Gyeonggi Agricultural Research & Extension Services, located in Shinseo-myeon, Yeoncheon-gun, Gyeonggi-do in 2015 in order to establish the standards for wide-shading facilities for energy-saving and labor-free system in response to Korea's climate and lack of manpower in rural area. The shading materials used were blue shading net made with coolaroo fabric, aluminum screen (shading rate 40%) and black shading net (shading rate 40%). As for the installation of additional shading materials, the blue shading nets (200 g/㎡ and 220 g/㎡) were installed on Apr. 1, and then the aluminum screens and black shading net were installed on Jun. 1 when it was hot (with the outside temperature of 30℃ or above. To determine the suitability of the shading materials, the growth environment in the shading facilities such as temperature and humidity, light quantity, and water leakage were measured. The growth was investigated for the above-ground part and underground part of the plants in accordance with the research standards of the Rural Development Administration (RDA). As for the temperature in the shading facilities, the temperature in the aluminum screen was higher than that of the black shading net, and the humidity in the aluminum screen was lower than that of the black shading net. The light intensity and transmittance were higher in the aluminum screen than those in the black shading net. The water leakage was absent on aluminum screen, but it was 8.1 - 11.5% in the black shading net. Although the growth of shoots above the ground showed no difference between shading materials, the growth of the shoot underground was better in the black shading net than in the aluminum screen in high temperature. In particular, the weight of Ginseng root increased by 19.1% in the black light shade compared to that of the aluminum screen. Conclusion : The results of the study showed that the combination of shading materials suitable for wide shading facilities in Korea in response to the lack of manpower in rural areas due to climate change and rural aging is the combination of "blue shading net + black shading net".

Background : This study is designed to select the best shading materials for the 4-year old ginseng K-1 variety by examining the light volume, photosynthesis and growth characteristics of ginseng. Methods and Results : The ginseng seedling was transplanted in the 7 lines x 9 rows (63 plants)/ 1.65 ㎡. The shading materials were installed in the form of rear line with 170 ㎝ high for front pole and 100 ㎝ high for rear pole. The installation of shading materials were installed in combination of polyethylene, blue polyethylene sheet + polyethylene, polyethylene + polyethylene, polyethylene + aluminium screen 70%, polyethylene + aluminium screen 100%, aluminium shade plate to inspect the photosynthesis and ginseng's growth characteristics. The photosynthetic rate was measured on the middle of small leaf using the photosynthetic tester (L1-6400, Li-COR) a t 10 : 00 – 14 : 00 on a clear day with the light volume of 100, 200, 400, 600, 800, 1,000, 1,400, 1,800 μmol s-1m-2.For the ginseng K-1, which is 4-years old, the aerial parts growth (such as survival rate, height of plant, length of stem, diameter of steam and length of leaf) and underground part (length, diameter and weight of root) were examined in 2016. As for the PAR (photosynthetically active radiation), the aluminum shade plate showed the best performance while the polyethylene + polyethylene showed the least. As for the photosynthetic rate, the following order was shown in the decreasing order: blue polyethylene sheet + polyethylene > polyethylene > aluminium shade plate ≒ polyethylene + aluminium screen 100%, > polyethylene + polyethylene > polyethylene + aluminium screen 70%. As for the survival rate for 4-year old ginseng, the polyethylene + aluminium screen 70% showed the highest survival rate with 91.0%. As for the growth of aerial part of ginseng, the polyethylene and polyethylene + polyethylene showed the best growth. As for the underground part of ginseng, the polyethylene, blue polyethylene sheet + polyethylene, and polyethylene + polyethylene showed the best growth in the length of roots and length of main root while polyethylene and blue polyethylene sheet + polyethylene showed the best growth in the weight of roots. Conclusion : In conclusion, considering the characteristics of photosynthesis and the underground parts of ginseng, it was found that the best shading materials for K-1 4-year old ginseng is blue polyethylene sheet + polyethylene.

Background : The study is designed to select the organic fertilizer as an additional fertilizer suitable for improving the yield of ginseng cultivar K-1 at low productive land when it is cultivated as 6-year old red ginseng. Methods and Results : This study was conducted in 2016 at a farm in Paju cultivating 6-year old ginseng root. As for the management of the cultivation land, in 2010 and 2011, Sudangrass was cultivated in order to make the organic matter content and chemical composition suitable for ginseng cultivation, and more than 15 tillage works were carried out a year. The transplantation was carried out at the planting density of 63 weeks / 1.62 ㎡ in April 2012. On May 2, the amount of 15 ℓ / 1.62 ㎡ of N 1.5 ㎏/1,000 ㎡ was supplied to the non-treatment, liquid fertilizer of fermented rice bran, liquid fertilizer of fermented soybean, seaweed and liquid yeast. N 1.5 ㎏/1,000 ㎡ was put into the soil for the fermented soybean and leaf mold. The photosynthetic rate was measured on the middle part of the small leaf by using a photosynthetic analyzer (LI-6400, Li-COR) at 10 : 00 - 14 : 00 on a clear day under PAR (photosynthetically active radiation) of 100, 200, 400, 600, 800, 1,000, 1,400, 1,800 μmol s-1m-2. The growth features of ginseng (including the length of stem, length of leaf, width of leaf, length of root and yield, etc.) as well as leaf discoloration, and root rot, etc were examined. The statistical analysis was performed 3 times in the randomized block design. For the rate of photosynthesis, the liquid fertilizer of fermented rice bran > liquid fertilizer of fermented soybean ≒ untreated ≒ fermented soybean > seaweed > liquid yeast > leaf mold was higher in that order. The survival rate ranged from 42.9% to 51.9%. As for the above-ground growth characteristics, the liquid fertilizer of fermented rice bran, liquid fertilizer of fermented soybean, seaweed and liquid yeast showed higher performance than the non-treated while the fermented soybean and leaf mold showed similar performance to the non-treatment. As for the underground growth, the liquid fertilizer of fermented rice-bran, liquid fertilizer of fermented soybean, fermented soybean, or leaf mold showed the same performance as non-treatment while the fermented soybean or leaf mold showed shorter length than non-treatment. As for the yield, the liquid fertilizer of fermented rice-bran, or liquid fertilizer of fermented soybean showed better performance than non-treatment. Conclusion : In conclusion, it was found that liquid fertilizer of fermented rice bran and liquid fertilizer of fermented soybean are the suitable organic fertilizers which can be used in ginseng cultivation for improving the quantitative yield of 6-year-old ginseng in low-producing area.

On June 14, 2008 (the first experiment) and July 24, 2008 (the second experiment), the shores of the Boseong River and the sandy beaches, Seokgok-myun, Moksadong-myun, Gokseong-gun in Jeollanam Province were investigated and a total of 29 soft-shelled turtle (Tryonyx sinensis) eggs in the natural spawning nest eggs were collected (13 eggs were collected in the first experiment and 16 eggs in the second experiment). The temperatures in the natural spawning nests were 25.9- 36.9±0.5℃, the depth of the eggs was 5.2-7.5±0.5 cm as the distance of the average 6.4±0.5 cm. 29 eggs were scattered at least 0.2 cm interval. Artificial incubation of 29 eggs was conducted in artificial nest boxes in thermo-plastic composition of the incubator, and then incubated at 26.5-35.5±0.5℃, and an average constant temperature was 31.2-32.1±1.0℃. The incubation days ranged from 53 to 55. In case of most turtles, incubation at 31℃ (higher temperatures) generally produces all or mostly females, while incubation at 25℃(cooler temperatures) produces all or mostly males. Exceptionally, in case of genus Trionyx, the sex ratio of female : male of T. sinensis of a freshwater soft-shelled turtle was approximately 1:1, which differs from other genera of turtles and makes T. sinensis Strauch only turtles presently known to lack temperature-dependent sex determination.

Background : Ginseng rain cover farming is expanding around Jinan county and Jangsu country of North Jeolla Province. Some farmers doing ginseng rain cover farming have suffered from difficulties due to hot weather damages. However, it is a situation that the study on mitigation techniques for high temperature damage do not exist with ginseng rain cover farming. Methods and Results : The test covering work was firstly done on April 28th for heat block film+90% black light blocking net, blue double sided film, and PE film+75% black light blocking net and when it comes to second treatment, 30% and 40% shading were implemented for heat block film group and blue double sided film group respectively and 75% black light blocking net was installed on PE film+75% shading group. When it comes to micro-climate measurement in rain cover facility, temperature, humidity and light intensity were measured during the growing period of ginseng. The results are as follows. Regarding the light transmittance (per PAR, 10 am in clear day) in facility with 1st covering, light block film covered group (LBF), blue double sided film group (BDF) and PE film group have 12.9±1.8%, has 11.6±1.0% and 27.1±1.1% respectively and after 2nd covering, in LBF groups, 30% blocking, 40% blcoking and no blocking have 10.6±1.3%, 8.2±0.9% and 12.9±1.8% and in BDF groups, 30% blocking, 40% blcoking and no blocking have 9.4±0.8%, 7.9±0.7% and 11.6±1.0 respectively and PE film group has 10.6±0.7%. Relative humidity also showed the same trend as temperature. The average monthly amount of light and maximum light intensity were lower in 30% and 40% light blocking groups of LBF and BDF and a little higher in no light blocking group compared to PE film group. The degree of high temperature damage was 1 in no LBF of BDF, but no LBF of LBF was so bad like 3. However, there was no high temperature damage in the test groups of blocking films or BDF with 30% and 40% light blocked light screens. Regarding root weight, all secondly treated groups of LBF group and BDF group were lighter compared to 4.36g of PE film group and especially, prism sheetof no light blocking group has 2.5g and BDF of of no light blocking group has 3.21g. 30 % and 40% light blocking groups of LBF group and BDF group were light with 3.20~4.07g. Conclusion : Regarding the analysis result on micro-climate in facility with different cover materials for 2 years old ginseng in ginseng rain cover farming of Gyeonggi Province, the covering method suitable for high temperature damage mitigation in ginseng rain cover farming was that 1st covering was done by PE film+75% black light blocking net and then 75% black light blocking net is additionally covered at a time when outside temperatures reaches 30℃.

Background : This study was carried out to distribute superior cultivars to farmers by analyzing growth characteristics of ginseng and effectively set the target for breeding by investigating annual agronomic characteristics of ginseng. Methods and Results : As a plant materials, Chunpoong (CP), Yunpoong (YP), Gopoong(GP), Gumpoong (GU) and Sunun (SU) were transplanted in Eumseong (ES), Geumsan (GS) and Yeoncheon (YC) on March 2013. Cultivation and management were conducted on the basis of the standard guidelines. According to stem and petiole by region, YC represent the largest stem diameter, leaf length and petiole length of cultivars, followed by those in ES and those in GS. Leaf growth of cultivars was overall the best in YC. Although CP had long and narrow leaves in all regions, YP and SU had short and narrow leaves. Root weight of all cultivars was the best in YC, but there was no significant differences by them. Growth of CP, YP and GP was generally good in ES. Growth of cultivars was relatively even in GS, but it was poor compared to cultivars which were cultivated in ES and YC. Conclusion : There were considerable differences in root growth of cultivars. However, this results suggest that CP of 4-year-old is produced stably in some regions because it had a small coefficient of variation.

Background : Recently, there is a urgent demand for development of new varieties with enhanced resistance to various biotic/abiotic stresses. In order to develop ginseng varieties with such traits, systematic breeding program and comprehensive field studies are prerequisite. Methods and Results : ‘Cheonmyeong' seeds were collected in 2008 from the farmer field of Buyeo. Physiological investigation and propagation were conducted from 2009 to 2011. It was given the name 'Eumseong No. 8 through the observed yield trial from 2012 to 2013 and local adaptability was carried out from 2014 to 2015. All phenotypes including agronomic characteristics, seed yield, and physiological response to biotic/abiotic stresses were investigated according to the ginseng GAP and UPOV guidelines. Yellow-red leaf and pink berry at maturing stage were observed. The time of emergence, flowering and berry maturity of the ‘Cheonmyeong’ were faster than those of ‘Chunpoong’. Stem length of ‘Cheonmyeong’ was shorter than that of ‘Chunpoong’, whereas stem diameter was thicker than that of ‘Chunpoong’. Main root length was shorter but main root diameter is thicker than that of ‘Chunpoong’. Number of seeds of ‘Cheonmyeong’ was fewer than that of ‘Chunpoong’ but 1,000-seeds weight and stratification rate were higher than those of ‘Chunpoong’. The yield performance of this variety was 661 kg/10 a in local adaptability test for two years, which is 22% higher than that of ‘Chunpoong’. ‘Cheonmyeong’ showed strong resistance to phytophthora blight, mulberry mealybug and nematode and moderate resistance to alternaria blight. ‘Cheonmyeong’ did almost not occur yellow spot of aerial part and rusty skin of root, show moderate resistance at high temperatures. Conclusion : Our study demonstrated that ‘Cheonmyeong’ is an ideal variety with heavier root weight and enhanced stress resistance and contribute will enhance biotic/abiotic stress resistance and increase the farmers' income.

Background : The research is designed to investigate the optimal cultivation technology and the growth of above-ground and below-ground sections as well as the photosynthetic characteristics for new ginseng variety “K-1” by differentiating the planting density under the conditions of transplanting and direct seedling. Methods and Results : The K-1 variety and hybrid variety (Jakyungjong) were selected for the research and the ginseng varieties were transplanted and directly sown in Yeoncheon area in 2013. The transplanting was made in the form of 5 lines × 9 rows (45 plants), 6 lines x 9 rows (54 plants), 7 lines × 9 rows (63 plants) and 8 lines × 9 rows (72 plants) in each lot (1.65㎡) while the direct seedling for testing was conducted three times in randomly blocked design in the form of 11 lines × 14 rows (154 plants), 12 lines × 14 rows (168 plants), 13 lines × 14 rows (182 plants). Various measures were collected from the 4-year transplanted ginseng and 3-year direct seedling ginseng in 2015 to find out the growth features and photosynthesis of above-ground section (rate of germination, leaf length, leaf width, stem length and leaf area index (LAI)) and the below-ground section (length, diameter, weight and class of roots). Conclusion : After the planting of the ginseng, the germination rate of K-1 for the transplanting was 85.1 ~ 92.0% across different plantation densities while that for the direct seedling was 67.7% ~ 77.9% across plantation densities, thus showing no significant difference between the two planting methods. LAI was higher for the higher planation density for both transplanting and direct seedling. As for the photosynthesis speed, the form of 6 lines × 9 rows showed the higher speed in transplanting while the form of 12 lines x 14 rows showed the higher speed in direct seedling. The photosynthesis of K-1 was higher than that of Jakyungjong. In the 4-year ginseng cultivated under the transplanting, diameter of roots, number of branch roots and weight of raw ginseng were the highest in the plantation density of 5 lines × 9 rows. The distribution of root weight was high with 23.3% and 20.0% for the 51~70g group and the 71g or above group, respectively, for the 4 year transplanted plants in the form of 5 lines × 9 rows. The growth for above-ground and below-ground sections for K-1 was better than that for Jakyungjong. As a result, it was found that the proper plantation density for the 4-year root in the transplanted K-1 was 5 lines × 9 rows considering the growth of the above-ground section, quantity and distribution of root weight.

Freesia is one of the most popular flowers over the world including Korea, due to the fragrance and beauty of the plant flower. The first domestic freesia cultivar ‘Shiny Gold’ was developed by NIHHS, RDA, in 2003, which has yellow double and large petals and strong fragrance. Ten years have passed since ‘Shiny Gold’ was cultivated at floral farms, and the deterioration of cut flower quality and yield are reported from the farms. Virus infection causes a reduction in the quantity and quality of the cut freesia flowers and is one of the most serious problems in Korea. Virus detection was carried by reverse transcription polymer chain reaction (RT-PCR) for FreMV, FreSV, BYMV, CMV, and TRV, as known to infect freesia. FreMV, FreSV, BYMV, and TRV were detected single or multiply, and CMV was not found in the freesia leaves collected from the farms. To produce virus-free freesia, meristem culture of ‘Shiny Gold’ was conducted in MS medium added ribavirin at different concentration. As the increased of ribavirin concentration, the growth of ‘Shiny Gold’ plantlets was inhibited in freesia’Shiny Gold’. The plantlets produced by meristem culture in ‘Shiny Gold’ were virus free at the enzyme-linked immunosorbent assay (ELISA) level.

The GA application on grapevines induces parthenocarpy, fruit set without fertilization, and the inhibition of pollen tube growth. But the molecular mechanism underlying this inhibition is not understood. Similar defective pollen tube growth within the transmitting tract has been reported in the mutant of GABA transaminase (GABA-T), referred to as pollen-pistil-interaction2 (pop2) in Arabidopsis. In spite of the similarity of pollen tube growth inhibition observed in GA-applied grapevines with that of pop2, only the effects of GABA on stress responses in grapevines have been reported. In present study, transcriptional changes of Vitis GABA metabolic genes, together with changes in GABA levels with or without GA application were analyzed to define how GA application restrained the pollen tube growth in grapevines. A GA solution (Dongbu, Seoul, Korea) at 100 ppm was onto inflorescence clusters 14 days before full bloom (DBF) and clusters were harvested at 0, 1, 2, 4, 7, 9, 12, 14, 16, and 19 days after GA application. Harvested inflorescence samples were immediately frozen in LN2 and extracted RNA and amino acid. The GABA contents were analyzed using high-performance liquid chromatography (Agilent 1100 HPLC, Agilent Technologies, Inc., Santa Clara, USA) equipped with a C18 column (4.6 mm×150 mm, 3.5 μm/VDS optilab, Berlin, Germany), according to the manufacturer’s instructions. Without GA application, the simultaneous high expressions of VvGAD1, VvGAD4 and VvGABA-T2 during 10 to 5 days before full bloom (DBF) showing the activation of GABA metabolism. But the contents of GABA were low before 2 DBF, and it peaked only at near full bloom when expression levels of VvGABA-T2 remained low. After GA application, the contents of GABA were constant during 10 to 5 DBF, although transcription levels of both VvGAD1 and VvGABA-T2 rapidly declined less than 30% of the levels observed without GA application. However, the GABA levels increased more than 2-fold only at near full bloom, compared to those without GA application, and at that time, expression levels of VvGAD1 up-regulated more than 3-fold and those of VvGABA-T2 kept low. But other amino acid contents did not show significant changes. In case of VvSSAHDs, their transcriptional changes with or without GA application were not correlated with GABA levels. These results indicates that GABA levels before pollination is tightly regulated, but GA application alters the GABA-shunt to accumulate excess GABA more than needed for proper pollen tube growth at full bloom. Gibberellin application alters the GABA-shunt to accumulate excess GABA resulting in inhibition pollen tube growth in grapevines.