• Korean Journal of Medicinal Crop Science
• /
• v.16 no.4
• /
• pp.238-241
• /
• 2008

Astragalus membranaceus have used as a medicinal herb and food in Korea. It is limited its harvest by diseases, pests and climate, therefore the main objective of Astragalus membranaceus breeding is the development of varities with the resistance for them. We used mutation breeding to obtain the genetic resources with the resistance for them. Pocheon, the local variety of Astragalus membranaceus, was treated with different levels Y-ray of $100{\sim}600$ Gy. There were investigated the sensitivity on germination and survival rate, plant height and the other characters. Germination rate from 4th day after sowing was significantly decreased above the 300 Gy as compared to the control. Compared to control, the decrements of survival rate were 32, 43, 63, 72, 84 and 89% for 100, 200, 300, 400, 500 and 600 Gy, respectively. The sensitive characters to Y-ray were plant height, number of branches per plant and survival rate, and the insensitive characters were number of leaves, length of leaf, and width of leaf. Plant height, number of branches per plant and survival rate seemed to be appropriate characters to decide the radiosensitivity, and radiation doses of $200{\sim}300$ Gy ($LD_{50}$) were recommend for mutation breeding.

• Journal of Life Science
• /
• v.31 no.4
• /
• pp.385-388
• /
• 2021

Anther cultivation for crop breeding is a method of rapid production of homozygosities by greatly reducing the time required for at least six generations to develop new varieties using conventional breeding methods. This technique of producing anther culture provides an opportunity to obtain more green plants from a methodological point of view, and the techniques that save time and effort in anther culture are also important because they increase the efficiency of culture. This study compared the callus induction rate and green plant regeneration rate of a one-step and a two-step culture that differ in their culture media and culture methods. One-step culture allows callus induction and plant regeneration in one medium, whereas two-step culture requires induction and plant regeneration in two different media. In this study, we compared the callus induction and plant regeneration rates of rice anthers as one-step and two-step cultures. The callus formation rate was 13.0% for one-step cultures and 8.6% for two-step cultures, so the rate was 4.4% higher for one-step cultures than for two-step cultures. The plant regeneration rate was 1.0% in one-step cultures and 3.0% in two-step cultures, so the regeneration rate was three times higher for the two-step cultures than for one-step cultures. This suggests that the two-step cultures are more efficient than the one-step cultures for haploid production.

• Korean Journal of Agricultural Science
• /
• v.41 no.1
• /
• pp.41-46
• /
• 2014

The pedigree data of 86,639 heads from six major swine breeding farms were investigated to check levels of inbreeding and effective population size of breeding stocks. The average rate of inbreeding was 1.04%, 0.87%, 3.17%, 1.05%, 3.23% and 3.33% for farms A, B, C, D, E and F, respectively. The average inbreeding rate was highest for F farm and lowest for B farm. In farms D and E, there were quite large numbers of immigrant animals per generation compared to other farms. The effective population sizes calculated from the average rate of inbreeding were distributed between 83.0 and 814.8. Specific values were 282.3, 225.5, 83.0, 814.8, 302.9 and 175.7 for farms A, B, C, D, E and F, respectively. The results showed that there was no cause for concern over the current inbreeding level of major swine breeding farm populations and the inbreeding level was within an acceptable range. In addition, internal sharing rather than importing pig is necessary to strengthen seed sovereignty.

• The Korean Journal of Malacology
• /
• v.26 no.2
• /
• pp.151-156
• /
• 2010

For industrialization of the hard clams, Meretrix petechiails (Lamarck), spawning was induced per spawning induction technique in the artificial maturation group administered of parent maturation control and the natural maturation group of which parents were transported for artificial spawning per time period. Then, fertilization rates, hatching rates and D-shaped larva development rates were investigated. In addition, growth and survival rates of larvae were investigated per larva breeding technique. The results of spawning induction by exposure in the artificial maturation group indicated that response rates were relatively higher at 23% and 32% respectively at the 4th hour and the 8th hour of exposure. In terms of water temperature increase, responses began only when the temperature reached $28^{\circ}C$ or higher. In the experiment group administered with both exposure and water temperature increase techniques, response rate was found to be 45% or higher at the 4th hour of exposure and the temperature of $28^{\circ}C$. At the temperatures of 29, 30 and $31^{\circ}C$, significant differences were not observed. Therefore, it was indicated that the response rates of parent hard clams were higher toward water temperature increase than exposure time. As for spawning induction per time period of the transported parent group, response rate and D-shaped larva development rate were the highest at 67.6% and 96% respectively on August 6, 2009. In terms of water temperatures during larva breeding experiment, growth was faster as water temperature was higher. In addition, growth and survival rates were relatively higher at the salinity of 25. In terms of stocking density, growth and survival rates were relatively higher at 5 inds./mL.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.20 no.1
• /
• pp.97-105
• /
• 2018

We assessed the effects of population density on the growth and survival rate of sea cucumber(Stichopus japonicus) in indoor tank Growth of S. japonicus in high density breeding was slow overall, and body weight on 250, 350 and 500 individual/m² group were 31.9g, 26.8g and 21.5g, respectively. The growth rate of body weight was 3.5~5.1 times according to the density of water, and the survival rate was 44.2~50.1%. The growth and survival rate were increased as decreasing the storage density. During the breeding season, small individuals tend not to be large and constantly culled, so it is necessary to set up the sorting period (etc.), and divide S. japonicus into groups of similar size.

• Asian-Australasian Journal of Animal Sciences
• /
• v.3 no.4
• /
• pp.287-292
• /
• 1990

1.86 million (Indigenous river, swamp, and swamp X river type) buffaloes are distributed mainly in the plain land, sugarcane belt and coastal area of Bangladesh and are raised by the small farm holders. Buffaloes per house-hold ranges from 5.79 to 2.12. Height at wither is $123{\pm}3.09$ and $112.5{\pm}2.15cm$ for buffaloes of central and eastern region respectively. Growth rate of buffalo calves ranges from 360 to 340 g/day. Late maturity ($1411.58{\pm}43.01d$) along with long life span facilitates farmers to use buffaloes longer period. Average daily milk yield is $2.32{\pm}0.63L$ with average lactation yield of $730{\pm}90l$ for $328{\pm}28.76d$. Both male and female individuals are used for draught purpose. A pair of buffalo can prepared $0.23{\pm}0.06ha$ of land daily and can work for $6.1{\pm}0.78hr$.

• Horticultural Science & Technology
• /
• v.17 no.4
• /
• pp.481-484
• /
• 1999

This experiment was conducted to examine the effects of chitosan and sucrose on the vase life of cut rose (Rosa hybrida L. cv. Cardinal). Addition of 5 mg/L chitosan and 3% sucrose to the holding solution prolonged the vase life for 3 days as compared to the control, and improved quality of cut rose in flower diameter and fresh weight. Development of bent-neck was delayed by supply of 2 mg/L or 5 mg/L chitosan and 3% sucrose about 2 or 3 days. When 3% sucrose was added to the holding solution, the rate of water absorption more slowly decreased compared to the other treatments.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.4
• /
• pp.431-435
• /
• 2015

Rice (Oryza sativa L.) ratooning is the production of a second rice crop from the stubble left behind after the main crop harvest. The objectives of this study were to evaluate the effects of main-crop stubble height, irrigation and fertilization on ratoon grain yield. Main crop 'Jinbuol' rice cultivar was harvested to leave with 10, 20, 30, or 40 cm stubble height. When the main crop stubble was harvested with 10 cm height, ratoon rice grain yield was increased by 2,810 kg/ha. Irrigation on stubbles after main crop harvest did not affect the ratoon crop yield and rice quality. The results showed a large variation in the ratoon performance by fertilizer application methods. Top-dressed nitrogen fertilizer on the stubble after harvest caused increase in panicle production and higher maturity rate. However, there was no significant difference in protein content, amylose content of milled rice and cooked rice characters between plots managed with and without nitrogen fertilizer.

• Korean Journal of Veterinary Service
• /
• v.36 no.2
• /
• pp.133-137
• /
• 2013

The purpose of this study was to investigate the seroprevalence of paratuberculosis in Korean cattle in western Jeonbuk area. From February 2012 to January 2013, blood samples were collected from 2,606 Korean cattle of 263 farms. As a result, 60 (2.3%) heads of 46 (17.5%) farms were positive on the ELISA test for paratuberculosis. Based on regional analysis, 18 (19.6%) out of 92 farms and 24 (2.5%) out of 941 heads in Iksan area, 28 (22.0%) out of 127 farms and 36 (2.8%) out of 1,291 heads in Kimje area were positive but samples from Gunsan area were all negative. According to scale breeding, small scale (below 50 heads) breeding showed the most high prevalence rate compared to middle (50 to 99 heads) or large (over 100 heads) scale breeding. To clarify the relation between number of heads and paratuberculosis prevalence, some additional analysis would be required in further, though.

• Korean Journal of Plant Resources
• /
• v.30 no.3
• /
• pp.318-322
• /
• 2017

The study was carried out to determine the changes of growth characteristics, anthocyanidin, and brown rice yield grown at coast and inland areas apart from the east coastline of Gyeongsangbuk-do province. Number of spikelets per panicle was much more increased in inland area. Regional difference in number of spikelets per panicle was observed in Jeongjinju cultivar. Among these red rice cultivars, the highest brown rice yield was Jeongjinju rice cultivar having 702 kg in inland area and 692 ㎏ in coast area, respectively. Anthocyanidin content ranged 524 to $610{\mu}g/g$ dry weight basis. Cyanidin content was 11.4 to 14.0 times higher than that of delphinidin under coast and inland area. Anthocyanidin content was higher in rice cultivar grown at coast area. Highest head brown rice rate was only observed in Geonganghongmi to 95.2 at coast area and 95.4 inland area. In considering brown rice yield and pigment content, Hongjinju rice cultivar was recommended in optimal pigment rice cultivar in eastern coast of Gyeongsangbuk-do Province.