• Korean Journal of Weed Science
• /
• v.17 no.2
• /
• pp.163-168
• /
• 1997

The experiment was conducted in 1996 to investigate distribution, germination characteristics, and effective control of Abutilon theophrasti in corn fields. The regional distribution of A. theophrasti showed that it was higher in Gyenggi province than in Kangwon, Chungnam, or Chonllanambug provinces because of many dairy farms located in Gyenggi province where fresh corn was used as ensilage. The optimal temperature of the weed seed germination was around 15~$20^{\circ}C$ and germination rate was 73~93% in 1~5cm of burial depth. The weed was able to be controlled effectively when treated 10 days after seeding more than just after seeding with herbicides, pendimethalin 31.7% EC, linuron 50% WP and pendimethalin linuron 25% EC with an acceptable phytotoxicity.

• Journal of the Korean Society of Tobacco Science
• /
• v.18 no.2
• /
• pp.126-131
• /
• 1996

In this study effects of isolation distance, transplanting time of maternal plants, and bagging of flower head with the gauze-cloth bag on the outcrossing of burley tobacco (Nicotiana tabacum L.) were investigated. Also the effect of fertilizer level and control of the number of capsules per plant on seed production and quality were examined. A male sterile line. produced 0.3 to 3.8 capsules Per plant when it was Planted with normally flowering tobacco with the average outcrossing of 7.2 plants, ranging from 2 to 18 out of 20 plants. With the farther the isolation distance between maternal plants and pollen donor plant, the lower the outcrossing occurred. Outcrossing occurred even at the isolation distance of 312 m. When the maternal plants were transplanted 35 days after transplanting the pollen donor ones, the outcrossed plants were not decreased significantly. The bagging of the flower head with the gauze-cloth bas (#0.9∼ 1.0 mm) decreased the outcrossed plants significantly, but couldn't prevent the outcrossing completely. The seed amount per plant was higher in the highly fertilized cultivation. The number of seed capsules per plant affected significantly on seed yield and quality. When the seed capsules was controlled by 30 or 50 capsules per plant, the weight of 1,000 seeds and germination rate were higher than those with 70 or 90 capsules per plant. Key words : Nicotiana tabacum, outcrossing, bagging.

• Korean Journal of Ecology and Environment
• /
• v.47 no.spc
• /
• pp.19-30
• /
• 2014

Microcystins (MCs) produced by cyanobacteria are severe hepatotoxins for mammalian and protein phosphatase inhibitors. Irrigation water for grain and vegetables is often contaminated with cyanobacteria and microcystin during warm seasons. We assessed the effects of various concentrations (0, 0.01 to $10{\mu}gmL^{-1}$) of microcystin-LR (MC-LR) and microcystin-RR (MC-RR) exposure on Oryza sativa (rice) and Brassica oleraces var. italica (broccoli). The $EC_{50}$ of leaves and roots of rice was 0.9 and $1.1{\mu}gMC-LRmL^{-1}$, respectively. The no observed effect level (NOEL) of rice was less than $0.1{\mu}gmL^{-1}$ ($100{\mu}gL^{-1}$). The $EC_{50}$ of the stems and roots of broccoli was 8.7 and $7.2{\mu}gMC-RRmL^{-1}$, respectively. There was no difference in the germination rate of broccoli among microcystin-RR concentrations. After exposure to 0, 0.01 to $10{\mu}gmL^{-1}$ MC-RR for seven days, 14, 89 and 154 ng mg-1 (dry weight) MC-RR accumulated in B. oleracea. These $EC_{50}$ values showed that microcystin-LR and -RR affected the growth of rice and broccoli. These findings suggest that MC is carried into terrestrial ecosystems via irrigation, and that the biota of higher ecological niches can be influenced by MC through bioaccumulation. Therefore, a guideline for MC concentrations in irrigation water should be set using the NOEL.

• Journal of agriculture & life science
• /
• v.51 no.2
• /
• pp.165-173
• /
• 2017

To evaluate performance of the experimental pick-up type pulse crop harvester for harvesting sprout bean, its pick-up and discharging grain loss ratios, grain quality such as whole grain ratio, damaged grain ratio, unthreshed grain, and foreign material ratio in grain tank, germination rate of threshed grain, and theoretical field capacity of the harvester were analyzed according to engine speeds of 2000, 2400 and 2800 rpm and harvesting speeds of 0.6, 1.0 and 1.4 m/s. It is considered that the harvester showed optimum performance at the engine speed of 2800 rpm and the harvesting speed of 1.0 m/s, and then average pick-up grain loss ratio of 2.7%, discharging grain loss ratio of 0.5%, whole grain ratio of 99.3%, damaged grain ratio of 0.2%, unthreshed grain ratio of 0.0%, foreign material ratio of 0.2%, and germination rate at 8 days after seeding of 72.8% were shown. It is considered that the harvester has lower grain loss and higher grain quality than the imported bean combines. And also as it could harvest 3 rows of cut and dried sprout bean crop width of which was about 2 m, its effective field capacity was estimated for about 50 a/h.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.167-167
• /
• 2022

Seed production of italian ryegrass has a problem of lodging during ripening and a decrease in quality due to difficulty in drying seeds during harvest. Therefore, in order to produce high-quality Italian ryegrass in paddy fields, it was carried out to reduce the density and solve the lodging problem through transplanting. In this experiment, Lolium multiflorum cv. Kowinearly was transplanted in autumn from a paddy field in Sindong-ri, Gwansan-eup, Jangheung-gun, Jeollanam-do. var. Kowinearly was made into a bed at 90 g/box and stacked in boxes. It was transplanted on October 27th after 2 days of germination at 30℃ and 15 days of seedling and greening. When transplanting, they were transplanted at intervals of 30×14cm. The existing cultivation method, drill seedling, was sowed at a level of 50 kg/ha, and both transplanting and drilling were carried out at a nitrogen fertilization rate of 45 kg/ha. The number of ears during transplant cultivation was 1,016/m² and the drilling tended to be higher at 2,278/m², but this was probably due to the difference in seeding amount. The seed number of an ear tended to be 56% higher in transplantation, which had a significant impact on yield. The seed yield was 2,096 ka/ha in transplantation, which was 21% higher than that of drilling. When looking at the relationship with weed occurrence, there were areas where all the weeds, such as amul foxtail, occurred due to the low density. Even in the same transplanting area, the seed yield was about 1,000kg/ha less in the area where the weeds were abundant. It seems that weed management is important in paddy cultivation. Therefore, it seems necessary to develop an exclusive herbicide for Italian ryegrass cultivation.

• Korean Journal of Plant Resources
• /
• v.29 no.1
• /
• pp.128-135
• /
• 2016

This study examined radiation damage and the optimal gamma-ray dose for mutation breeding in oat (Avena sativa L. cv. Samhan). The seed germination rate decreased as the dose increased over 500 Gy. The median lethal dose (LD₅₀) was approximately 392 Gy. The median reduction dose (RD₅₀) for plant height, tiller number, root length, and flash weight was 411, 403, 394, and 411 Gy, respectively. The optimal dose of gamma irradiation for inducing oat mutation appears to be in the range 300-400 Gy. We performed the comet assay to observe nuclear DNA damage induced by gamma-ray irradiation. This assay showed a clear difference with gamma-ray treatments. DNA damage increased temporarily 7 days after treatment depending on the dose, while no significant difference was identified in response to 300 Gy 30 days after the gamma-ray treatments. The growth characteristics of the M₂ generation decreased as the dose increased over 400 Gy.

• The Plant Pathology Journal
• /
• v.37 no.1
• /
• pp.57-71
• /
• 2021

Rice sheath blight (ShB), caused by Rhizoctonia solani Kühn AG1-IA, is one of the destructive rice diseases worldwide. The aims of this study were to develop biocontrol strategies focusing on field sanitation and foliar application with a biocontrol agent for ShB management. Streptomyces padanus PMS-702 showed a great antagonistic activity against R. solani. Fungichromin produced by S. padanus PMS-702, at 3.07 mg/l inhibited 50% mycelial growth, caused leakage of cytoplasm, and inhibited the formation of infection structures of R. solani. Fungichromin could reach to 802 mg/l when S. padanus PMS-702 was cultured in MACC broth for 6 days. Addition of 0.5% S. padanus PMS-702 broth into soil decreased the survival rate of the pathogen compared to the control. Soil amended with 0.5% S. padanus broth and 0.5% tea seed pomace resulted in the death of R. solani mycelia in the infested rice straws, and the germination of sclerotia was inhibited 21 days after treatment. Greenhouse trials revealed that S. padanus cultured in soybean meal-glucose (SMGC-2) medium after mixing with different surfactants could enhance its efficacy for inhibiting the pathogen. Of six surfactants tested, the addition of 2% tea saponin was the most effective in suppressing the pathogen. S. padanus broth after being fermented in SMGC-2, mixed with 2% tea saponin, diluted 100 fold, and sprayed onto rice plants significantly reduced ShB disease severity. Thus, S. padanus PMS-702 is an effective biocontrol agent. The efficacy of S. padanus PMS-702 for disease control could be improved through formulation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.35 no.4
• /
• pp.342-351
• /
• 1990

Experiments were conducted to find out the possibilities of producing good quality seed of summer type soybean at Chuncheon, 74m above sea level and Jinboo, 600m above sea level in 1987. Local variety, Cheonan Jaelae was used. Seeds were sown June 25 harvested five times from 35 days after flowering with five days interval to 55 days. Vegetative period was longer in the early planting and high cool area, Jinboo, which resulted longer stem length than the late planting and in the plain area, Chuncheon. Pod number and 100 grain weight were shown more and heavier in Jinboo. Earlier planting and later harvesting resulted more pod number and heaveier 100grain weight. Grain yield was heigher in Jinboo, and earlier plainting shown more grain yield and its difference was greater in Jinboo. Long grain filling duration resulted more grain yield. Unripened seeds were produced more by earlier planting with earlier harvesting and earlier planting with late harvesting showed the high rates of pod and stem blight (Diaporthe Phaseolorum). Seed With high moisture content by early harvesting showed more rotten seeds in all planting dates production was more advantageous in the high cool area, Jinboo. Optimum planting date was between May 15 and June 5. Harvesting was desirable about 45-50 days after flowering with heigher germination rate seed yield.

• Journal of Korean Society of Forest Science
• /
• v.102 no.1
• /
• pp.66-73
• /
• 2013

This study was conducted to determine the effects of rice hull cover on seed germination and tray types, soil types, shading conditions for seedling growth of Codonopsis pilosuala. We also examined the feasibility of cultivation of small seedlings transplanted in the Gyeonggi-do area for a month. Under control condition, the seed germination was 8% whereas it dramatically increased to 78% under rice hull cover treatment. Under the different conditions (tray types, soil types, and shading conditions), young seedlings showed the best quality without shading in TKS soil of 50 plug cell tray, with the growth characteristics of plant height (11.9 cm), number of leaves (71), leaf width (3.1 cm), leaf length (2.6 cm), and root length (14.3 cm). Seedling quality was the best without any shading in TKS+perlite, with the physiological characteristics of evaporation (3.9 $mmol{\cdot}m^{-2}s^{-1}$), carbon assimilation (9.1 ${\mu}mol{\cdot}m^{-2}s^{-1}$), and water use efficiency (2.2 ${\mu}mol{\cdot}m^{-2}s^{-1}$). Considering the economical, morphological, physiological and survival rate of the seedlings, it was an ideal method for transplanting seedlings in the field after they have been grown for 30-45 days in TKS and TKS+perlite of 200 plug cell tray in 0% or 30% shaded conditions. As the results of 5 months examination on the possibility to cultivate Codonopsis pilosuala in the Gyeonggi-do area, 88% to 96% of survival rate was observed with normal induced flowers. Therefore, cultivation of Codonopsis pilosuala was possible in the Gyeonggi-do area. While there were symptoms of etiolation and wilting under no shading condition, they did not appear in 30% and 70% shading conditions. Therefore, cultivation of Codonopsis pilosuala is considered to be necessary 30% or 70% shading.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.2
• /
• pp.201-207
• /
• 2014

The changes of growth characteristics and antioxidant activity for selection of optimum germinated temperature on common bean (Phaseolus vulgaris L.). Common beans (IT100888, IT102849, and IT231267) were cultivated at $20^{\circ}C$, $23^{\circ}C$ and $25^{\circ}C$ during 5 days of germination. The range of whole length, hypocotyls length, thickness, abnormal germination and yield rate of sprouts was 7.27~27.62 cm, 3.10~18.86 cm, 1.80~2.27 mm, 5.54~18.34% and 205.95~ 618.71%, respectively. Antioxidant activities of common beans with germination temperature investigated. Common beans (IT100888, IT102849, and IT231267) germinated at $20^{\circ}C$, $23^{\circ}C$ and $25^{\circ}C$ during 5 days, and then extracted with 80% ethanol, and analyzed for total polyphenol content, DPPH and ABTS radical scavenging activity. Total polyphenol content increased from 474 mg GA eq/100 g sample for IT231267 to 1364 mg GA eq/g sample for $23^{\circ}C$ of germination. DPPH radical scavenging activity of IT102849 increased from 189mg Trolox eq./100 g sample ($20^{\circ}C$) to 1073mg Trolox eq./100 g sample ($23^{\circ}C$) also ABTS radical scavenging activity of IT234267 increased from 479 mg Trolox eq./100 g sample ($20^{\circ}C$) to 1134 mg AA eq/100 g ($23^{\circ}C$). These results suggest that germination temperature for increasing antioxidant activities may be $23^{\circ}C$.