• Journal of The Korean Society of Grassland and Forage Science
• /
• v.6 no.3
• /
• pp.164-168
• /
• 1986

This study was conducted at the forage experiment field of SNU, Snweon to investigate effects of sowing time and seeding rate on growth characteristics, winter survival and dry matter yield of forage rye (Secale cereale L.) as fresh-cut forage. Treatments involved 9 combinations of sowing times (September 8, 28 and October 18) and seeding rates(80, 130 and 180kg $ha^{-1}$). Plant height was not influenced by the time of sowing, but forage rye had a tendency to be taller as increasing seeding rate when sown on September 8 and October 28 and harvested in fall and spring, respectively, Winter survival was reduced by fall harvesting in the plot sown on September 8, however, total dry matter yield was increased by the fall harvesting. Average dry matter yields of 5884, 4993 and 3525kg $ha^{-1}$ were obtained when forage rye was sown on September 8, 28 and October 18, respectively. Dry matter yield was decreased as delaying the time of sowing, but a tendency toward higher yield of forage rye by increasing seeding rate was observed. Yield difference by seeding rates was markedly larger when forage rye was sown on October 18 than September 8 and 28. Based on the results of this study, it appears that the dry matter yield of forage rye could be enhanced by sowing early to late September under upland condition in the middle plain are of Korea. The seeding rates of 80 to 130 kg $ha^{-1}$ and 180kg $ha^{-1}$ would be suitable for early to mid fall and late fall sowings, respectively.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.16 no.1
• /
• pp.1-8
• /
• 1996

The objective of this study is to obtain the basic data for investigating the effects of organic reserves on winter survial or regrowth yield. Forage rape (Brussicu napus L.) was sown at 10 day> interval from Sep. I to Nov. 1. Field-grown palnts were sampled on the before wintering (Dec. 4) and on the wintering period (Jan. 16) to analyze the nitrogen and non-structural cahohydrate reserves. The rate of winter survival and regrowth yield were also measured in the spring of next year. On the before wintering, the dry matter yields from the plots sown on Sep. 1, Sep.11 and Sep. 21 were 860, 596 and 260 kg/lOa, respectively. No. harvest was canied out on the plots sown after Oct. 1 because the growth state was not enough to cut. Both of nitrogen and starch contents per plant significantly increased as the seeding date was later. On the wintering period, the contents of nitrogen reserves in roots were 176.8. 120.1, 71.7, 84.0, 72.1, 45.3 and 33.3 mg/plant, those of starch reserves were 199.0. 55.8, 21.8, 92.6, 86.5, 36.4 and 29.0 mglplant, resepctively, in the plots sown on Sep. 1, Sep. 11, Sep. 21, Oct. I, Oct. 11, Oct. 21 and Nov. 1. The rates of winter survival were 40, 36, 33, 85, 87, 59 and 49% and regrowth yields were 161, 86, 65, 520, 451, 121 and 33 kgD.M/lOa, respectively, in each plots. 'Ihese results clearly showed that seeding date has a close influence on the level of organic reserves and forage yield, and that the possibility of continuous utilization on the before and alter wintering is extremely limited by seeding date.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.37 no.2
• /
• pp.100-104
• /
• 2018

The rearing of black soldier flies in Korea is affected by seasonal factors such as temperature and sun light; for this reason, it requires a great deal of effort to rear and maintain black soldier flies during the winter. In this study, we investigated how starvation affects larval development. After hatching the larvae, they were fed for 5 or 10 d and then starved for a certain period to see how they recovered. The length and width of larvae were estimated to be 18.18 to 21.96 mm, 5.19 to 6.04 mm, respectively. Larvae survivorship to the pupal stage was significantly different between groups and periods of starvation. The groups of fed for 5 d then starved showed a high survival rate until 20 d starvation and then the survival of larvae rapidly decreased. The survival rate of the larvae was abruptly decreased for 20 d starvation in the groups of fed for 10 d and starved, and then gradually decreased until 60 d starvation thereafter. Our research attempted to influence larvae development through starvation and provides basic information on how to culture the black soldier fly effectively and economically throughout the year.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.28 no.1
• /
• pp.48-53
• /
• 2000

This study was carried out to investigate the growth characteristics and propagation methods of Prunus species as woody landscape plants. Both the flowering time and the survival rate of grafting were investigated. The results are obtained as follows: The total of flowering period of Prunus species in Kyonggi province area lasted for about 26 days. The flowering time of the species overlaps. These observations suggest that the possibility of interspecific pollination among Prunus species is very high in the kyonggi province area. The total number of flowers in the species in area was in as follows decreasing order : (1) Prunus yedoensis >Prunus pendula var. ascendens > Prunus subhitella > Prunus sesrulata for. fugenzo > Prunus leveillenana var. pendula. The number of carpels in each flower ranged from 0.3 for Prunus subhirtella to 1.8 for Prunus serulata for. fugenzo. In the caseof Prunus sesrulata for. fugenzo, the carpels appeared to be degenerated and thus losted their function. However, there exist two tyoes of Prunus subhirtella. While one type had normal carpel, the other had the degenerated one. The survival rate of grafting was investigated on May 19. Eighty there percent of the plants survived when the grafting was made in the greenhouse in January whereas the plants grafted in nursery in March survived less in that Prunus suhirtella showed 64%, Prunus leveilleana var. pendula 47%, Prunus sesrulata for. fugenzo 43%, Prunus yedoensis 62% and Prunus pendula var. ascendens 24%, respectively. Therefore, it suggested that high humidity and optimal temperature appeared to incase the survival rate of the grated plants. We therefore propose here that grafting should be done in the greenhouse that both humidity and temperature could be controlled to enhance the efficiency of grafting. This will enable as to perform grafting in winter as well.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.12 no.4
• /
• pp.218-225
• /
• 1992

This experiment was carried out to compare the varietal differences of winter hardiness based on the values of winter hardiness index(W1) and the dry weight of plant per relative tiller appearance rate (DWIRTAR), and the evaluate the method of measurements for winter hardiness in 17 orchardgrass varieties grown under mountainous area of Tackwalyon, Kangwon-do. Korea. The results were summarized as follows: 1. Seedling vigours(SV) of plant before wintering indicated highly significant negative correlation with the dry weight of 1st cutting(DW) and the dry weight of plant per relative tiller appearance rates (DWIRTAR). 2. The dry weight of 1st cutting(DW) indicated significant positive correlations with the number of tillers per plant(NT). dry weight of a tiller(WT), lield survival rate(SR). heading rate(HR) and the dry weight of heading tillers(HDW). 3. Correlation coefficients of the dry weight of 1st cutting(DW) with winter hardiness index(W1) was 0.499(p<0.05), and the dry weight of plant per relative tiller appearance rates(DW/RTAR) was 0.895(p<0.001), respectively. 4. Between the winter hardiness index(W1) and field survival rate(SR) showed highly significant positive correlation(p<0.001). And, the dry weight of plant per relative tiller appearance rates(DW/RTAR) showed highly significant positive correlation(p<0.001) with the dry weight of a tiller(WT) and the dry weight of heading tillers(HDW). 5. The varieties were classified into 2 groups by winter hardiness index(W1). The 13 varieties of Hallmark. lna, Rancho, Amba, Filippa, Sparta, Hokuto, Kitamidori, Okamidori, Wasemidori, Shinyo, Potomac and Summer-green belong to the group of W1)100, and 4 varieties of Able, Juno, Napier and Jesper belong to the group of WI(100, respectively. 6. And, also classified into 2 groups by the dry weight of plant per relative tiller appearance rates (DWIRTAR). The 4 varieties of Amba, Okamidori, Wasemidori and Summer-green belong to the group of DW1RTAR)l.O and 13 varieties of Able, Hallmark, Ina, Juno, Napier, Rancho, Filippa. Jesper, Sparta, Hokuto, Kitamidori, Shinyo and Potomac belong to the group of DW/RTAR(1.0, respectively. The variety with DW/RTAR)I.O is belong to the group of high potential winter hardiness, and also obtained a high values over the 100 of winter hardiness index(W1). 7. The dry weight of plant per relative tiller appearance rates(DW/RTAR) may be a very useful ecological character to evaluate the potential winter hardiness of orchardgrass varieties grown under mountainous area of Taekwalyon(altitudinal ranges about 800m).

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.54 no.3
• /
• pp.260-264
• /
• 2009

Sufficient seedling establishment of Chinese milk vetch (CMV) is the most important factor in the CMV cultivation. In order to obtain sufficient seedling stand, CMV seed should be planted at right seed planting date. An optimum CMV seed planting time for stable seedling establishment was determined based on the final water drainage time for rice harvest in fall. Five planting times from 10 days before water drainage (DBWD) to 15 days after water drainage (DAWD) at five day interval were evaluated during the period of 2006-2007 and 2007-2008 and the optimum CMV seed planting time was determined based on seedling stand, winter survival rate, and dry matter production. CMV seedling stand before winter was high with $575{\sim}1,050\;plants/m^2$ regardless of seed planting times but after overwintering, it was greater in seed planting date between 5 DBWD to 5 DAWD than that of 10 to 15 DAWD treatments. Winter survival rate, dry matter production and seed production yield also showed similar trend to the seedling establishment. On the other hand, when CMV seeds were sowed early at 10 DBWD, seedling stand and winter survival rate were lower than that of 5 DBWD to 5 DAWD. This result indicates that an optimum CMV seed planting time based on the final water drainage could be between 5 DBWD (September 20) to 5 DAWD (September 30).

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.36 no.4
• /
• pp.340-343
• /
• 2016

The present study investigated the effects of different seeding rates on growth characteristics and seed productivity of the "Kowinearly" cultivar of Italian ryegrass (Lolium multiflorum Lam.) in paddy fields. Sowing Kowinearly in paddy fields under growing rice at the rates of 20, 30, 40, and 50 kg/ha resulted in seed yields of 1.57, 1.92, 2.06, and 2.09 ton/ha, respectively. Seed yield of Kowinearly was the highest at a seeding rate of 50 kg/ha (p<0.05), at which the cultivar was able to survive in winter and the weed ratio was low. Under these conditions, most growth characteristics such as winter survival (85%), weed ratio (10%), stems per square meter (1,006) were superior than those sown at other seeding rates (p<0.05). In addition, it has been reported that the economic efficiency of the 50 kg/ha seeding rate was higher than that of the other seeding rates.

• Proceedings of the Korean Aquaculture Society Conference
• /
• 2003.10a
• /
• pp.28-28
• /
• 2003

Viable interspecific hybrids between yellowtail flounder (Pleuronectes ferrugineus, Store.) and winter flounder (Pleuronectes americanus, Walbaum) were produced by artificial insemination of yellowtail flounder eggs with winter flounder sperm. However, mean fertilization rate, hatching success and early survival up to 3 weeks post hatch were significantly lower than those of parental pure cross controls (P<0.01). Overall, cytogenetic traits (karyological analysis and estimation of cellular DNA contents using flow cytometry) of hybrid flounder were intermediate between the two parental species. Microsatellite assay was used to distinguish the parental genomes in the hybrids; in most cases, one allele was specific to each of the parents. Morphometrics assessed by body proportions indicated that hybrids generally displayed a morphology intermediate between the maternal and paternal species. Interspecific hybrids exhibited abnormal and retarded gonad development in both sexes based on histological analysis of gonads from adult fish. The sterility of the hybrids presents a significant advantage for their use in aquaculture, as potential escapees would not be capable of reproducing in the wild and contaminating natural stocks.

• Korean Journal of Weed Science
• /
• v.30 no.3
• /
• pp.291-299
• /
• 2010

Cyhalofop-butyl and penoxsulam, known for respective acetyl CoA carboxylase (ACCase) and acetolactate synthase (ALS) inhibitor, have been widely using as a post-emergence foliar application for many years in wet-seeded rice field in Korea. Since 2009, control of Echinochloa oryzoides with cyhalofop-butyl and penoxsulam was no longer satisfactory. Greenhouse and experiment in rice field were conducted to confirm E. oryzoides resistance to ACCase and ALS inhibitors and to compare herbicide treatments for control of the resistant E. oryzoides to ACCase and ALS inhibitors. Three resistant E. oryzoides to ACCase and ALS inhibitors accessions were tested for levels of resistance to cyhalofop-butyl and penoxsulam, base on survival rate. Iksan and Kimje accessions were not any affected to the survival by treatment with recommended doses of two herbicides tested. Buan accession displayed an intermediate response of 62 and 72% survival at recommended doses of cyhalofop-butyl and penoxsulam, respectively. Survival rates to herbicides mixed with ACCase and ALS inhibitors at 3.5 leaf stage of E. oryzoides was over 80%. Benzobicyclon+fentrazamide+bensulfuron SC, benzobicyclon+mefenacet+bensulfuron SC, benzobicyclone +cafenstrole+pyrazosulfuron-ethyl GR controlled effectively by 2 leaf stage of resistant E. oryzoides to ACCase and ALS inhibitors. In the field experiment, single treatment of benzobicyclon+ fentrazamide+bensulfuron SC and benzobicyclon+mefenacet+bensulfuron SC failed to control E. oryzoides, but squential treatment of benzobicyclon+thiobencarb SE and benzobicyclon+ mefenacet+ bensulfuron SC controlled effectively it in rice infant seedling culture with machine. Our results suggest that resistant E. oryzoides to ACCase and ALS inhibitors had not developed multiple resistance to herbicides with different modes of action. In particular, cafenstrole, fentrazamide, mefenacet were effective control measures.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.21 no.1
• /
• pp.149-157
• /
• 2019

This study interested on management of broodstock and the effect of raise the temperature for promotion of maturity in Tresus keenae. For management of broodstock, we performed indoor and outdoor culture. In addition, broodstock was put in exposure and immersion condition. This experimental design is aimed at knowing the optimal management of broodstock. In addition, we investigated the promotion of maturity, growth and survival rate when raise the temperature of the breeding seawater of broodstock in winter season. Result that, the management of broodstock was shown to be more effective obesity and survival rate in outdoor culture than indoor culture. In addition, there is no anthropogenic food supply in management and it is easy to management because it is kept under natural environmental conditions. Therefore, It is considered appropriate to management to outdoor culture. In raise the temperature, survival rate was lower in the experimental group than in the control group. However, obesity was significantly increased compared with the control group. Also, gonad showed that the sex maturity was promoted. If sex maturation is not developed due to seasonal water temperature, the promotion of sexual maturity through heating is considered to be an effective method in terms of artificial seed production.