• Asian-Australasian Journal of Animal Sciences
• /
• v.14 no.12
• /
• pp.1705-1711
• /
• 2001

Silage corn (Zea mays L) is grown extensively in livestock operations, and many managements focus on forage yield. This experiment was conducted at Seoul National University (SNU) Experimental Livestock Farm, Suwon in 1998. We determined the effect of planting date and harvest stage on forage yield and quality responses of corn hybrids (five relative maturity groups). The five maturity groups (100 d, 106 d, 111 d, 119 d and 125 d) were planted on 15 April and 15 May, and harvested at maturity stages (1/3, 1/2 and 2/3 kernel milkline). Whole plant dry matter (DM) and ear percentages had significant differences among corn hybrids. Ear percentages of early maturing corns (100 d and 106 d) were higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date for all corn hybrids. The DM and total digestible nutrients (TDN) yields of the 106 d and 111 d corn hybrids were higher than other hybrids, and the DM and TDN yields at the early planting date were higher than that at the late planting date. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) percentages were greater for the late maturity corn hybrids. For plants of the early planting date, the ADF and NDF percentages were lower than for those of late planting date for hybrids. From the comparison among harvest stages, ADF and NDF percentages were decreased as harvest stage progressed. The TDN, net energy for lactation (NEL), and cellulase digestible organic matter of dry matter (CDOMD) were decreased as maturity of corn hybrid delayed. The TDN, NEL, and CDOMD values at the early planting date were higher than those at the late planting date among for corn hybrids. From the comparison among harvest dates, TDN, NEL, and CDOMD values were increased as harvest stage progressed. The correlation coefficient for DM percentage of grain at harvest with DM and TDN yields were 0.68*** and 0.76***, respectively. And the correlation coefficient for ear percentage with ADF, NDF, and CDOMD were -0.81***, -0.82*** and 0.73***, respectively. Our study showed differences of silage corn in forage production and quality resulting from hybrid maturity, planting date, and harvest stage. We believe that for the best silage corn, selection of the hybrid and best management practices are very important.

• Research in Plant Disease
• /
• v.15 no.3
• /
• pp.222-229
• /
• 2009

A Pseudomonas strain SG3 producing biosurfactant and showing antifungal and insecticidal activities was isolated from agricultural soil severely contaminated with machine oils. The antagonistic bacterium inhibited mycelial growth of all of the tested fungal pathogens. The fermentation broth of SG3 also effectively suppressed the development of various plant diseases including rice blast, tomato gray mold, tomato late blight, wheat leaf rust, barley powdery mildew and red pepper anthracnose. An antifungal substance was isolated from the fermentation broth of SG3 by ethyl acetate partitioning, silica gel column chromatography and preparative HPLC under the guide of bioassay. The chemical structure of the antifungal substance was determined to be rhamnolipid B by mass and NMR spectral analyses. The antifungal biosurfactant showed a potent in vivo antifungal activity against gray mold and late blight on tomato plants. In addition, rhamnolipid B inhibited mycelial growth of B. cinerea causing tomato gray mold and zoospore germination and mycelial growth of P. infestans causing tomato late blight. Pseudomonas sp. SG3 producing rhamnolipid B could be used as a new biocontrol agent for the control of plant diseases occurring on tomato plants.

• Korean Journal of Weed Science
• /
• v.1 no.1
• /
• pp.52-56
• /
• 1981

A 2-year field experiment was conducted to determine the influence of early and late soybean (Clycine max Merr) seeding times on competitive relationships between soybeans and annual weeds. Soybeans were planted on May 20 and June 20. Durations of weed competition and weed control were 0, 3, 6, 9, and 12 weeks after planting sad for full growing season. Dominant weeds were Portulaca oleracia, Centipeda minima, Rorippa cantonienais, Chenopodium album, Acalypha australis, Echinochloa crusgalli, and Digitaria sanguinalis. The dry weight of weeds increased with extended competition, especially at early seeding time of soybeans. Soybean yields were decreased as duration of weed competition was extended. More severe yield reduction occurred at late-planted soybeans with early stage weed competition but at early-planted soybeans when weeds competed with soybeans for a 2 weeds and full growing season. The dry weight of weeds emerged after weeding was decreased at early and late seeding times of soybeans as duration of weed control was prolonged. Soybean yields decreased with shortening duration of weed control end this trend of yield reduction was slightly more remarkable at late-planted soybeans than at early-planted soybeans. Late-planted soybeans were required longer than 6 weeks of weed control period to achieve maximum yield as compared to early-planted soybeans.

• Development and Reproduction
• /
• v.5 no.1
• /
• pp.17-21
• /
• 2001

This study was conducted to investigate the expression pattern of Trypsin-like enzyme and the effect of a trypsin inhibitor(benzimidine) on hatching process during in-vitro culture of mouse preimplantation embryos. The Trypsin-like enzyme was identified by rhodamine-conjugated Trypsin substrate probe. The expression of trypsin-like enzyme was firstly detected at the late morula stage, and the enzyme was uniformly localized in the trophectoderm of late blastocysts. Especially, intense fluorescence was observed in the blebbing area of hatching blastocysts. Bisbenzamidine, contained in culture media, did not alter embryonic development from 4-cell stage to the expanded blastocyst but decrease the hatching rate in ImM concentration (15.8% vs 89.7%, p<0.02). In the treatment of bisbenzimidine (5mM) for 12 hours according to the embryonic stage of mouse, the hatching rate of control (83.0%) and treatment in late blastocysts (8.7%) were significantly (p<0.01) different. From these results, we suggested that the hatching enzyme having trypsin-like activity was localized from the late morula stage, and the hatching process by this enzyme was activated in the late blastocyst stage of mouse embryos.

• Korean Journal of Animal Reproduction
• /
• v.20 no.4
• /
• pp.459-465
• /
• 1997

The present study was undertaken to determine the effect of NT time on the rate of fusion a and suhseguent development In vitro and determine the optimal strength and duration of DC pulse for electrofusion of IVF donor embryo nuclei and IVM recipient oocytes. The recipient oocytes were enucleated 25 ~ 2Sh after IVM and further cultured for 18 ~ 20h prior to fusion for oocyte aging. IVF embryos as donor nuclei were C co cultured with BOEC for 16- to 32-cell stage development. The transfer time of donor bIas tomeres was 1~3h post-enucleation in early NT group and 1 ~ 18h post-enucleation in late NT group, respectively and fusion was performed 43~4Sh post-IVM. The fusion rate did not differ between the early NT and late NT group, but the rate of cleavage and 8- to 16-cell stage embryos in the late NT group was more higher than that in the early NT group. The fusion, cleavage and M+B development was high from O.7SkV /cm DC than from 1.0kV /cm DC voltage, resulting in 17.6% M+B from 0.75kV /cm DC voltage. No difference in fusion rate was among pulse durations, but 50 and 70 usec pulse duration showed slight high cleavage and M + B d development. The results indicate that the best NT time of IVF donor blastomeres into the enucleated oocytes was 42~44 post-IVM and the most suitable condition for electrofusion was a single 0.7SkV /cm DC voltage for SO~70$\mu$sec.

• Asian Journal of Turfgrass Science
• /
• v.23 no.1
• /
• pp.123-132
• /
• 2009

This study was designed to investigate the effect of the late fall fertilization applied with methyl urea(MU), compound chemical fertilizer(CF), humate(HM), and organic compost fertilizer(NS) on spring greenup of creeping bentgrass at following year. The plots were treated with various snow cover periods before transforming to ski slopes from golf holes during 2007 fall to 2008 spring. The highest visual quality and greenup rate were shown on MU or HM applications at 10 days before snow cover treatment. The CF treatment which had a highest phosphorus rate was most effective with a 13 cm of root length at the reconversion date to golf hole from ski slope of the following spring. However, the application of CF followed by immediate snow cover showed the worst results on visual quality and green color caused by a leaf burning damage from the residual effect of CF. At least 10 days were required to avoid phytotoxicant from undissolved granular of CF before snow cover practise. The application of NS showed the highest result on leaf dry weight at no snow cover plot in next spring, but not on green color and visual quality. Therefore, the proper interval period of snow cover after late fall fertilization should be an important management skill on the spring greenup of creeping bentgrass on following year transforming from ski slope to golf hole.

• The Korean Journal of Pesticide Science
• /
• v.15 no.3
• /
• pp.303-309
• /
• 2011

This study was carried out to investigate the evaluation of insecticidal efficacy and control effect in field of 10 environmental-friendly agricultural materials (EFAM) and seasonal occurrence at the vineyards to the Lycorma delicatula. L. delicatula nymphs occurred from late May to late August the highest early June (1st nymph) while adults occurred from late July to November with the highest peak of early October (preovipositing female) in 2010. Total population density of L. delicatula was the highest in early June. For the 3rd~4th nymphal instars and adults, EFAM (Spider, Jindikap-plus and Byejin-${\alpha}$) showed perfect insecticidal activity 2hour after treatment. Seoncho showed insecticidal activities 96.7% within 48 hour. Residual effects between EFAM showed 55.5% Spider at recommended concentration at 7 days after treatment(DAT), the other EFAM had low efficacy. Jindikap-plus and Spider showed 99% control value on nymphs in the field test at 3DAT, appeared control value more than 90% at 7DAT. Also, the control effects of Jindikap-plus and Spider were showed the adult mortality of 100% and 98.2% respectively at 3DAT, 90.6% and 84.6% respectively at 7DAT. Whereas the other EFAM had low efficacy. Jindikap-plus and Spider were excellent control effects compared with Acetamiprid WP.

• Korean Journal of Agricultural Science
• /
• v.43 no.3
• /
• pp.346-352
• /
• 2016

This study was conducted to obtain the correlation between the plant surface spray adhesion amount of pesticides and the pest control effect. The linearity of the standard curves of dinotefuran and thiodicarb was $R^2=0.9999$, and recovery was between 70% to 120% which was satisfactory for insecticide residue analyses. The pest control effect was evaluated by assessing the number of apple leafminers (Phyllonorycter ringoniella, Gracillariidae, Lepidoptera) captured by sex pheromone traps from late June to late September in 2015. For the adhesion amount, dinotefuran recovered from trap A and B, respectively were $47{\mu}g/50cm^2$ and $23{\mu}g/50cm^2$, which can be characterized as a very low adhesion amount in comparison to the average adhesion amount of $81{\mu}g/50cm^2$ in the field. In case of thiodicarb, $691{\mu}g/50cm^2$ and $71{\mu}g/50cm^2$ were recovered from trap A and B, respectively, and the average amount in the field is $325{\mu}g/50cm^2$. These results showed close correlation with the insect population captured by trap A and B. The numbers of insects captured by trap A and B between the end of July and late August were similar. After spraying thiodicarb on August 28, the number of apple leafminers captured by trap B is bigger than that of trap A. It appears that pest occurrence tended to be high at low adhesion amounts of the active ingredient. Therefore, in order to obtain an optimal control effect, it is suggested that uniform application of insecticides is critical instead of relying on the amount of insecticide applied in the field.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.1
• /
• pp.41-44
• /
• 2007

The callipyge mutation in sheep is a polar overdominant mutation that results in post-natal muscle hypertrophy in the loin and hindquarters of paternal heterozygotes (+/CLPG). Sheep that are homozygous for the callipyge allele (CLPG/CLPG) do not express the muscle hypertrophy phenotype, but serve as carriers for the mutation. Callipyge sheep are characterized by improved feed efficiencies and leaner carcasses. Leptin is a protein hormone secreted from adipose tissue and has been found to affect appetite and serve as an indicator of body fat mass. To date, very little knowledge is available as to the effect of the callipyge mutation on circulating leptin levels. Due to the interaction of leptin with feed intake and energy availability, and the fact that the majority of fetal growth occurs in late gestation, it is important to understand if the callipyge mutation interacts with leptin production in late gestational ewes. Therefore, our objective was to characterize serum concentrations of leptin in late gestational callipyge ewes vs. non-callipyge ewes. We evaluated genetically verified callipyge (n=6), homozygous (n=8) and normal (n=8) ewes weekly during the last eight wks of gestation through one wk post-partum. Weights were taken and body condition scores were assigned by trained personnel weekly. Blood was collected via jugular venipuncture on each sampling date and subjected to an ovine-specific leptin RIA. Genotype influences on peripheral concentrations of leptin were found to be highly significant (p=0.0005). Total leptin means for +/CLPG were 5.41${\pm}$0.40 ng/ml, CLPG/CLPG 8.11${\pm}$0.70 ng/ml, and +/+ 9.13${\pm}$0.93 ng/ml. Sampling date was also significant (p=0.0098) with all ewes showing a decrease in leptin levels throughout gestation and parturition. Using repeated measures, we were able to detect lower levels of plasma leptin in callipyge ewes, which may be indicative of their lower overall body fat content. These results indicate that the callipyge phenotype decreases the levels of adipose tissue and leptin production in gestating ewes.

• Korean Journal of Child Studies
• /
• v.38 no.1
• /
• pp.233-249
• /
• 2017

Objective: This study examined the effects of maternal grandmothers' positive parenting behavior and mothers' self-differentiation and positive parenting behavior on self-concept in late childhood. Methods: A total of 341 $5^{th}$- and $6^{th}$- grade elementary school children and their mothers participated in the study. Children were surveyed regarding perceptions of their mothers' positive parenting behavior and their own self-concept. Mothers responded to questionnaires regarding both positive parenting behavior of their mothers and their own self-differentiation. The data were analyzed using SEM. Results: Maternal grandmothers' positive parenting behavior had an indirect effect through mothers' self-differentiation and positive parenting behavior on children's self-concept. Mothers who perceived positive parenting behavior in their mothers in their childhood showed positive parenting behavior (as perceived by their children), and those children reported a higher level of self-concept. Mothers who perceived their mother's parenting behavior in their childhood more positively reported a higher level of self-differentiation, and those mothers showed more positive parenting behavior (as perceived by their children), which led to more positive self-concept in children. Conclusion: The findings specify the pathways from maternal grandmothers' positive parenting behavior to children's self-concept through mothers' self-differentiation and positive parenting behavior in an aspect of the intergenerational transmission of parenting. The findings also emphasize the importance of mothers' positive parenting behavior for positive self-concept in late childhood.