• ALGAE
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• v.39 no.2
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• pp.109-127
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• 2024

High production and efficient harvesting of microalgae containing high omega-3 levels are critical concerns for industrial use. Aeration can elevate production of some microalgae by providing CO₂ and O₂. However, it may lower the production of others by generating shear stress, causing severe cell damage. The mixotrophic dinoflagellate Gymnodinium smaydae is a new, promising microalga for omega-3 fatty acid production owing to its high docosahexaenoic acid content, and determining optimal conditions and methods for high omega-3 fatty acid production and efficient harvest using G. smaydae is crucial for its commercial utilization. Therefore, to determine whether continuous aeration is required, we measured densities of G. smaydae and the dinoflagellate prey Heterocapsa rotundata in a 100-L semi-continuous cultivation system under no aeration and continuous aeration conditions daily for 9 days. Furthermore, to determine the optimal conditions for harvesting through centrifugation, different rotational speeds of the continuous centrifuge and different flow rates of the pump injecting G. smaydae + H. rotundata cells into the centrifuge were tested. Under continuous aeration, G. smaydae production gradually decreased; however, without aeration, the production remained stable. Harvesting efficiency and the dry weights of omega-3 fatty acids of G. smaydae + H. rotundata cells at a rotational speed of 16,000 rpm were significantly higher than those at 2,000-8,000 rpm. However, these parameters did not significantly differ at injection pump flow rates of 1.0-4.0 L min^-1. The results of the present study provide a basis for optimized production and harvest conditions for G. smaydae and other microalgae.

• Journal of The Korean Society of Grassland and Forage Science
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• v.19 no.1
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• pp.89-94
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• 1999

This experiment was carried out to determine harvest date and cultivar effects on growth characteristics, forage yield and quality of spring sown oats at the middle mountain(450m) area at the forage experimental field, Namweon Branch, National Livestock Research Institute. The experiment was arranged in a split plot design with three replication. The main plot consisted of the harvest date(9 June, 18 June). The subplots consisted of different maturities of oat cultivars such as Cayuse, Swan, Foothill, Cashel, Martlock and Winjardie. The results obtained are summarized as follows; A period of 50 days was required to be first headed from seeding with early maturity oats(Swan), but that of 77 days was required with late maturity(Foothill). The dry matter content of early maturity(Swan) oats at 9 June and 18 June were 24.01% and 35.69%, but that of late maturity cultivars(Foothill) were 14.02% and 22.84%. The fresh yield of late maturity(Foothill) oats at 9 June and 18 June were 62,666kg and 59,666kg, but that of early maturity(Cashel) were 54,222kg and 45,493kg(P<0.05). The dry yield of early maturity (Cashel) oats at 9 June was 10,169kg, but that of early maturity (Martlock) was 6,272kg. But no significant difference was found among cultivars at June 18. Crude protein content of oats were decreased from 14.0% to 11.1% as the growing stage progressed, ADF, NDF and CF contents were increased. And in vitro dry matter digestibility was decreased as the harvest date delayed. The present experiment indicated that spring sown oats(Foothill) can be successfully produced as fresh forage by seeding in middle March and harvesting in 10 and 20 June at the middle mountain (450m) area.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.103-112
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• 1995

Six African rice varieties, two each from three types having the characteristics of partially, irregularly, and completely developed abscission layers, were selected and grown 1） to investi-gate the histological differences during the formation and development of the abscission layers and 2） to evaluate the changes in the breaking tensile strength required to detach a grain from its pedicel dur-ing ripening period in relation with developmental stage of the abscission layers. In African rice, the panicle and spikelet grew rapidly from 15 days before heading and almost completely grown in length at five days before heading. The abscission regions were recognized at 15 days before heading. However, any apparently developed abscission layers were not recognized in the lemma side for partially developed abscission layers. A group of parenchymatous cells could be observed sporadically in the abscission layers of the lemma side for irregularly developed ab-scission layers. At ten days before heading, abscission layers consisting of one or two layers of parenchymatous cells were clearly distinguished from neighboring cells due to thickened and lignified cell walls. There were a number of individual parenchymatous cells scattered sporadically in the lemma side of partially developed abscission layers, and a number of grouped parenchymatous cells scattered randomly in the lemma side of irregularly developed abscission layers. At two weeks after heading, the grains became almost fully filled. The cracking of abscission layers between rachilla and pedicel was observed, and the breaking tensile strength required to detach a grain from its pedicel was as low as that at harvest time.

• Korean Journal of Weed Science
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• v.16 no.1
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• pp.8-13
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• 1996

This study was conducted to know the effect of storage period, harvesting time and light condition on dormancy breaking of major weeds. Echinochloa crus-galli, Cyperus serotinus, Aeschynomene indica, Ludwigia prostrata and Bidens tripartita had the 10 or 30% germination ability within 30 days after harvest but scirpus juncoides, Potamogeton distinctus, Aneilema japonica and Monochoria vaginalis had not germination untill 120 days after harvest of seed. C. serotinus and P. hydropiper required strong light for germination but S. juncoides, L. prostrata and B. tripartita showed the less tham 5% germination in the dark condition gerntinator. S. juncoides germination showed negative response in chemical soaking but A. japonica, B. tripartita and L. prostrata showed high germination percentage in Acetone, Chloroform and distilled water soaking during the 10 days after treatment.

• The Plant Pathology Journal
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• v.24 no.4
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• pp.439-446
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• 2008

A fungicidal spray program for effective control of three major apple diseases in Korea (white rot, bitter rot, and Marssonina blotch) was developed. This was based on our previous studies showing that application of ergosterol biosynthesis inhibitors (EBIs) in early or mid-August can eradicate white rot infection in fruit and that some protective fungicides show after-infection activity against white rot. The basic spray program focused on control of white rot, the main target disease, and the fungicides were sprayed at 15-day intervals from petal fall to late August using fungicides that show after-infection and EBI activity. The basic spray program was modified over 4 successive years to improve control efficacy against bitter rot and Marssonina blotch, which sometimes cause as much damage as white rot. Modifications to the regime were made every year by replacing one fungicide in the basic program at a specific spraying time. Substitution of only one fungicide in the spray program, even early in the growing season, greatly influenced the final disease incidence at harvest. Applying this principle, a moderately efficient spray program for cv. Fuji that increased the spray interval from 10 to 15 days and thus reduced the number of sprays required per crop season was developed.

• Korean Journal of Plant Resources
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• v.22 no.2
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• pp.136-144
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• 2009

Germination tests on 3 species that have potential for use as sprout vegetables, such as Coreopsis tinctoria, Saussurea pulchella, and Matricaria recutica, were conducted for 20 days under different temperatures of $15{\sim}30^{\circ}C$, and conditions of light and dark. C. tinctoria showed germination of 83% under $15^{\circ}C$ and dark condition after 4 days, S. pulchella 51.7% under $25^{\circ}C$ and light condition after 20 days, and M. recutica 90.3% under $25^{\circ}C$ and dark condition after 4 days. To investigate optimum plantlet size before greening treatment, seeds germinated were allowed to grow under darkness. The optimum growth of C. tinctoria was obtained under $30^{\circ}C$ after 5 days, S. pulchella under $25^{\circ}C$ after 6 days, and M. recutica under $20^{\circ}C$ after 6 days. Greening treatment resulted in diminished longitudinal growth, but C. tinctoria and S. pulchella showed more vigorous latitudinal growth. Days required before marketing as sprout vegetables were different according to species - Three days of greening was good for C. tinctoria, 2 for S. pulchella, no greening for M. recutica. Generally, tightly sealed containers for minimum water loss were recommended for storage of sprout vegetables after harvest. However, storage methods for each species were different depending on various factors like temperature of storage, presence of ventilation holes of storage packages and forms of marketing. More detailed research for above 3 species is proposed.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.71-80
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• 1995

This experiment was conducted to investigate the effect of raising seedling methods of cold water, low night temperature, and abandoned mine on forcing culture of strawberry. The results were as follows ;1. $17^{\circ}C$ cold water alone and cold water plus 8-hour short day treatments significantly accelerated the flower bud differentiation of Nyoho cultivar to 11 and 15 days, respectively, comparing to common soil raising seedling.2. The date of flower bud differentiation of Nyoho cultivar as influenced by cold water treatment the 17th, the 13th and the 10th of September, respectively, when the seedlings were treated on the 10th of September and on the 25th and the 10th of August in 1991. In 1992, data showed that the flower bud differentiation dates were the 4th and the 2nd of September and the 29th of August when cold water treatment was done on the 10th of August and on the 25th and the 10th of July.3. The first harvest date when Nyoho cultivar was treated by cold water for 30days from Jul. 25 was Nov. 10, this implying that the harvesting day could advanced to 19 days comparing to that by the common soil raising seedling method. The resulting yield was recorded to 21.94 ton per hectare.4. Regardless of the starting date of the treatment, $13^{\circ}C$ low night temperature plus 8-plus short day treatments for 20 days required 17 days to differentiate the flower bud of Nyoho cultivar. Harvesting day could be advanced to 59 days comparing to that by the common raising seedling method when the seedling was treated on July 25, this resulting in increasing the total yield obtained by April 14 of following year to 8.25 ton per hectare.5. When the seedlings of both Nyoho and Hokowase cultivars were raised under the condition of abandoned mine, flowering and harvest date were earlier by the treatment for 20 days than that for 30 days or 40 days. The highest yiesd obtained was recorded in Nyoho cultivar or 1.88 ton per hectare.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.267-272
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• 2012

Overcoming harsh light environment, as well as increased growth of crops even in high-quality production can play an important role when using the LED light system of photosynthetic products will be able to effectively reduce consumption. In this study, low efficiency of farm greenhouses, growing annual reduction in income due to rising operating costs and increase crop growth by inducing the proper planting environment Factory-type raise farmers' income and at the same time will contribute to the increase of Light device using LED Supplemental through photosynthesis, promote and improve product quality, plant growth regulators are considered possible for them to develop more efficient LED devices and LED Optical processing devices of Light leaf lettuce grown using normal fluorescent or incandescent bulbs grown in the results than the growth can see that the speed improvements. Usually shipped from seedling to harvest leaf lettuce from 25 to 30, whereas optical processing device be required red light (wavelength: 645nm) using a leaf of lettuce grown enough to be harvested after seven days increased the rate of growth. In addition, red light (wavelength: 645nm) and blue light (wavelength: 470nm) emitting at the same time, room, and grown for 5 days to harvest the growth rate was fast enough.

• Journal of Mushroom
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• v.12 no.3
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• pp.187-192
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• 2014

In order to breed a new P. eryngii cultivar with high temperature tolerance trait to cope with climate change, strains and cultivars were characterized at $20^{\circ}C$ that is $5^{\circ}C$ higher than normal condition followed by screening for the characteristics such as required days to harvest, quality and yield. Monokaryons from the selected strains were crossed. $Da-32{\times}KNR2322-15$ derived from the crosses between KNR2322 having characteristics of short growing day and Da($Ga5Na5-4{\times}KNR2312-7$) having charateristics of high guality and yield at $20^{\circ}C$, showed 14.9 days for harvest, 120.6 g yield, and 7.0 quality in the first trial. The strains were named as Taeyangsongi and cultivated on a large scale to compare with Kenneutari No. 2 at a mushroom farm. Yield of Taeyangsongi (109 g) was significantly different(P=0.001) from Kenneutari No.2. Quality of the new (6.6) and the reference cultivar (3.5) was also statistically different (P=0.001) The brightness of pileus of Taeyangsongi (59.5) was 10 points less than the reference cultivar due to which it has an inability to bear high temperature stress. Thus, PCR reactions with URP2 discriminated between Taeyansongi and reference cultivars (Keneutari No. 2 and Aeryni).

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.1-8
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• 2012

Rapid loss of grape berry quality after harvest occurs due to poor postharvest management. Understanding physiological properties between cultivars is required to develop practical technologies to control fast quality deterioration of tables grapes. Physiological characteristics of whole cluster, rachis and berries were examined to find their effects on postharvest behaviour of table grapes. 'Tamnara' showed high respiration rate and browning of rachis compared to 'Campbell Early'. Weight loss of rachis of 'Cheongsoo' was highest of three cultivars. Berry decay in 'Cheongsoo' begins at the connection portion between peduncle and berry, and berry decay of 'Cheongsoo' was the most severe among three cultivars. Precooling at $0^{\circ}C$ showed better results than cooling at $10^{\circ}C$ regardless of cultivars but cooling effect decreased when simulated marketing period increased up to 10 days. Plastic film wrapping was effective on reducing decay in general but not at higher marketing temperature. For successful commercialization of newly developed grapes, the inhibition technology of rachis browning in 'Tamnara' is required and decay control in 'Cheongsoo' through establishment of cold chain system is recommended.