• Proceedings of the KSAR Conference
• /
• 2001.03a
• /
• pp.31-31
• /
• 2001

This study was to establish in uitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, This study was to establish in vitro culture system of mouse preantral follicles and to obtain higher in vitro development rates and production of live young. Preantral follicles were obtained from 12-day-old FI mouse (C57BL $\times$ CBA) by enzymatical methods. Oocyte-granulosa cell complexes (OGCs) of preantral follicles were loaded on Transwell-COL insert and cultured in $\alpha$MEM supplemented with 5% FBS, 100 mIU/$m\ell$ FSH and 100 mIU/$m\ell$ hMG for IVG. IVM was performed in $\alpha$MEM supplemented 1.5 IU/$m\ell$ hCG for 18 hrs and IVF was carried out in Ml6 medium. Embryos were cultured in modified Ml6 medium supplemented 10% FBS for 4 days. The effect of the OGCs size on the nuclear/cytoplasmic maturation was significantly higher in 120-150 ${\mu}{\textrm}{m}$ (MII: 33.0%, $\geq$2-cell: 36.7%, $\geq$morula: 20.9%) than in 70-110 ${\mu}{\textrm}{m}$ (MII: 12.2%, $\geq$2-cell: 10.2%, $\geq$morula: 4.8%) (p<0.001). In period of the IVG days, the rate of $\geq$2-cell was significantly higher in 10 days(38.2%) than in 12 days (20.0%) (p<0.01). In period of IVF time, 9 hrs ($\geq$2-cell: 31.5%, $\geq$ morula: 14.3%) indicated significantly higher cytoplasmic maturation rate than 4 hrs ($\geq$2-cell: 17.5%, $\geq$morula: 4.8%) and 7 hrs ($\geq$2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.morula: 4.8%) and 7 hrs (2-cell: 20.4%, $\geq$morula: 6.1%) (p<0.01). However, there was no difference in cytoplasmic maturation between co-cultured preantral follicle ( $\geq$morula: 17.4%) and preantral follicle cultured in Ml6 ( $\geq$morula: 17.4%). 22 morula and blastocysts produced in above optimal condition were transferred to uterus of 2 pseudopregnant recipients, 1 recipient was pregnant and then born 1 live young. This result demonstrates that in vitro culture system of preantral follicles can be used efficiently as another method to supply mouse oocyte.

• Horticultural Science & Technology
• /
• v.32 no.6
• /
• pp.872-878
• /
• 2014

This study aimed to enhance storage and freshness of strawberry fruits and foliage vegetables by spray treatment with Chlorella vulgaris as a bio-fertilizer. The tested strain, C. vulgaris CHK0008, was isolated from an organically cultivated rice paddy and identified as C. vulgaris by its morphology and 18S rDNA and 23S rDNA sequence homology. We successfully cultured C. vulgaris CHK0008 in BG11 modified medium (BG11MM) and adjusted $2.15{\times}10^6cell/mL$ C. vulgaris CHK0008 to one OD value by measuring the optical density at 680 nm using a UV-vis spectrophotometer. The soluble solid content of 'Seolhyang' and 'Yukbo' strawberry fruits treated by spray application with C. vulgaris CHK0008 was enhanced by 22.2% and 11.5% respectively, compared to untreated controls. Additionally, the decay rates of treated 'Seolhyang' and 'Yukbo' strawberry fruits decreased 63.8% and 74.4% respectively, compared to untreated control. Surface color changes and chlorosis of leaves in leaf vegetables such as lettuce, kale, red ornamental kale, white ornamental kale and beet were observed in samples treated with water spray for 10 days after cold storage. However, the decay rate of leafy vegetables treated with foliar application of 25% C. vulgaris CHK0008 liquid culture was significantly decreased compared to that of the untreated control during storage at $4^{\circ}C$.

• Applied Biological Chemistry
• /
• v.37 no.3
• /
• pp.182-188
• /
• 1994

Similar to the $^{42}K$ uptake, $^{86}Rb$ uptake by the roots of Hordeum distichum grown in the hydroponic culture was negatively correlated with the concentration of K supplied previously, showing that $^{86}Rb$ can be used for the K-bioassay. $^{86}Rb$ having longer half life (18.86 day) than $^{42}K$ (12.36 hr) allowed the use of larger number of root samples. $^{86}Rb$ uptake of 3 years old Citrus unshiu Marc. grown in water culture decreased drastically with the increase of K concentration of the culture solution, thus demonstrating that the nutrition status of K for citrus trees can be diagnosed by K-bioassay using $^{86}Rb$ tracer. $^{86}Rb$ uptake by the excised roots of Hordeum distichum grown in the pot with different K fertilizations was well correlated with the exchangeable K in soil. The amount of exchangeable K in soil for the optimal plant growth can be determined by its relationship. $^{42}K$ and $^{86}Rb-uptake$ by the Hordeum distichum roots were markedly inhibited by $5{\times}10^{-3}\; M$ KCN in the bioassay solution, indicating that uptake is energy-dependent. There was no significant relationship between K content in citrus leaves and K concentration in the water-culture medium. It is concluded that K-bioassay is a potentially useful tool for determining of K requirement in citrus trees.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.16 no.2
• /
• pp.3361-3394
• /
• 1974

The purpose of this thesis is to disclose some characteristics of water consumption in relation to the quantities of dry matters through the growing period for two statured varieties of paddy rice which are a tall statured variety and a short one, including the water consumption during seedling period, and to find out the various coefficients of evapotranspiration that are applicable for the water use of an expected yield of the two varieties. PAL-TAL, a tall statured variety, and TONG-lL, a short statured variety were chosen for this investigation. Experiments were performed in two consecutive periods, a seedling period and a paddy field period, In the investigation of seedling period, rectangular galvanized iron evapotranspirometers (91cm${\times}$85cm${\times}$65cm) were set up in a way of two levels (PAL-TAL and TONG-lL varieties) with two replications. A standard fertilization method was applied to all plots. In the experiment of paddy field period, evapotanspiration and evaporation were measured separately. For PAL-TAL variety, the evapotranspiration measurements of 43 plots of rectangular galvanized iron evapotranspirometer (91cm${\times}$85cm${\times}$65cm) and the evaporation measurements of 25 plots of rectangular galvanized iron evaporimeter (91cm${\times}$85cm${\times}$15cm) have been taken for seven years (1966 through 1972), and for TONG-IL variety, the evapotranspiration measurements of 19 plots and the evaporation measurements of 12 plots have been collected for two years (1971 through 1972) with five different fertilization levels. The results obtained from this investigation are summarized as follows: 1. Seedling period 1) The pan evaporation and evapotranspiration during seedling period were proved to have a highly significant correlation to solar radiation, sun shine hours and relative humidity. But they had no significant correlation to average temperature, wind velocity and atmospheric pressure, and were appeared to be negatively correlative to average temperature and wind velocity, and positively correlative to the atmospheric pressure, in a certain period. There was the highest significant correlation between the evapotranspiration and the pan evaporation, beyond all other meteorological factors considered. 2) The evapotranpiration and its coefficient for PAL-TAL variety were 194.5mm and 0.94∼1.21(1.05 in average) respectively, while those for TONG-lL variety were 182.8mm and 0.90∼1.10(0.99 in average) respectively. This indicates that the evapotranspiration for TONG-IL variety was 6.2% less than that for PAL-TAL variety during a seedling period. 3) The evapotranspiration ratio (the ratio of the evapotranspiration to the weight of dry matters) during the seedling period was 599 in average for PAL-TAL variety and 643 for TONG-IL variety. Therefore the ratio for TONG-IL was larger by 44 than that for PAL-TAL variety. 4) The K-values of Blaney and Criddle formula for PAL-TAL variety were 0.78∼1.06 (0.92 in average) and for TONG-lL variety 0.75∼0.97 (0.86 in average). 5) The evapotranspiration coefficient and the K-value of B1aney and Criddle formular for both PAL-TAL and TONG-lL varieties showed a tendency to be increasing, but the evapotranspiration ratio decreasing, with the increase in the weight of dry matters. 2. Paddy field period 1) Correlation between the pan evaporation and the meteorological factors and that between the evapotranspiration and the meteorological factors during paddy field period were almost same as that in case of the seedling period (Ref. to table IV-4 and table IV-5). 2) The plant height, in the same level of the weight of dry matters, for PAL-TAL variety was much larger than that for TONG-IL variety, and also the number of tillers per hill for PAL-TAL variety showed a trend to be larger than that for TONG-IL variety from about 40 days after transplanting. 3) Although there was a tendency that peak of leaf-area-index for TONG-IL variety was a little retarded than that for PAL-TAL variety, it appeared about 60∼80 days after transplanting. The peaks of the evapotranspiration coefficient and the weight of dry matters at each growth stage were overlapped at about the same time and especially in the later stage of growth, the leaf-area-index, the evapotranspiration coefficient and the weight of dry matters for TONG-IL variety showed a tendency to be larger then those for PAL-TAL variety. 4) The evaporation coefficient at each growth stage for TONG-IL and PAL-TALvarieties was decreased and increased with the increase and decrease in the leaf-area-index, and the evaporation coefficient of TONG-IL variety had a little larger value than that of PAL-TAL variety. 5) Meteorological factors (especially pan evaporation) had a considerable influence to the evapotranspiration, the evaporation and the transpiration. Under the same meteorological conditions, the evapotranspiration (ET) showed a increasing logarithmic function of the weight of dry matters (x), while the evaporation (EV) a decreasing logarithmic function of the weight of dry matters; 800kg/10a x 2000kg/10a, ET=al+bl logl0x (bl>0) EV=a2+b2 log10x (a2>0 b2<0) At the base of the weight of total dry matters, the evapotranspiration and the evaporation for TONG-IL variety were larger as much as 0.3∼2.5% and 7.5∼8.3% respectively than those of PAL-TAL variety, while the transpiration for PAL-TAL variety was larger as much as 1.9∼2.4% than that for TONG-IL variety on the contrary. At the base of the weight of rough rices the evapotranspiration and the transpiration for TONG-IL variety were less as much as 3.5% and 8.l∼16.9% respectively than those for PAL-TAL variety and the evaporation for TONG-IL was much larger by 11.6∼14.8% than that for PAL-TAL variety. 6) The evapotranspiration coefficient, the evaporation coefficient and the transpiration coefficient and the transpiration coefficient were affected by the weight of dry matters much more than by the meteorological conditions. The evapotranspiratioa coefficient (ETC) and the evaporation coefficient (EVC) can be related to the weight of dry matters (x) by the following equations: 800kg/10a x 2000kg/10a, ETC=a3+b3 logl0x (b3>0) EVC=a4+b4 log10x (a4>0, b4>0) At the base of the weights of dry matters, 800kg/10a∼2000kg/10a, the evapotranspiration coefficients for TONG-IL variety were 0.968∼1.474 and those for PAL-TAL variety, 0.939∼1.470, the evaporation coefficients for TONG-IL variety were 0.504∼0.331 and those for PAL-TAL variety, 0.469∼0.308, and the transpiration coefficients for TONG-IL variety were 0.464∼1.143 and those for PAL-TAL variety, 0.470∼1.162. 7) The evapotranspiration ratio, the evaporation ratio (the ratio of the evaporation to the weight of dry matters) and the transpiration ratio were highly affected by the meteorological conditions. And under the same meteorological condition, both the evapotranspiration ratio (ETR) and the evaporation ratio (EVR) showed to be a decreasing logarithmic function of the weight of dry matters (x) as follows: 800kg/10a x 2000kg/10a, ETR=a5+b5 logl0x (a5>0, b5<0) EVR=a6+b6 log10x (a6>0 b6<0) In comparison between TONG-IL and PAL-TAL varieties, at the base of the pan evaporation of 343mm and the weight of dry matters of 800∼2000kg/10a, the evapotranspiration ratios for TONG-IL variety were 413∼247, while those for PAL-TAL variety, 404∼250, the evaporation ratios for TONG-IL variety were 197∼38 while those for PAL-TAL variety, 182∼34, and the transpiration ratios for TONG-IL variety were 216∼209 while those for PAL-TAL variety, 222∼216 (Ref. to table IV-23, table IV-25 and table IV-26) 8) The accumulative values of evapotranspiration intensity and transpiration intensity for both PAL-TAL and TONG-IL varieties were almost constant in every climatic year without the affection of the weight of dry matters. Furthermore the evapotranspiration intensity appeared to have more stable at each growth stage. The peaks of the evapotranspiration intensity and transpiration intensity, for both TONG-IL and PAL-TAL varieties, appeared about 60∼70 days after transplanting, and the peak value of the former was 128.8${\pm}$0.7, for TONG-IL variety while that for PAL-TAL variety, 122.8${\pm}$0.3, and the peak value of the latter was 152.2${\pm}$1.0 for TONG-IL variety while that for PAL-TAL variety, 152.7${\pm}$1.9 (Ref.to table IV-27 and table IV-28) 9) The K-value in Blaney & Criddle formula was changed considerably by the meteorological condition (pan evaporation) and related to be a increasing logarithmic function of the weight of dry matters (x) for both PAL-TAL and TONG-L varieties as follows; 800kg/10a x 2000kg/10a, K=a7+b7 logl0x (b7>0) The K-value for TONG-IL variety was a little larger than that for PAL-TAL variety. 10) The peak values of the evapotranspiration coefficient and k-value at each growth stage for both TONG-IL and PAL-TAL varieties showed up about 60∼70 days after transplanting. The peak values of the former at the base of the weights of total dry matters, 800∼2000kg/10a, were 1.14∼1.82 for TONG-IL variety and 1.12∼1.80, for PAL-TAL variety, and at the base of the weights of rough rices, 400∼1000 kg/10a, were 1.11∼1.79 for TONG-IL variety and 1.17∼1.85 for PAL-TAL variety. The peak values of the latter, at the base of the weights of total dry matters, 800∼2000kg/10a, were 0.83∼1.39 for TONG-IL variety and 0.86∼1.36 for PAL-TAL variety and at the base of the weights of rough rices, 400∼1000kg/10a, 0.85∼1.38 for TONG-IL variety and 0.87∼1.40 for PAL-TAL variety (Ref. to table IV-18 and table IV-32) 11) The reasonable and practicable methods that are applicable for calculating the evapotranspiration of paddy rice in our country are to be followed the following priority a) Using the evapotranspiration coefficients based on an expected yield (Ref. to table IV-13 and table IV-18 or Fig. IV-13). b) Making use of the combination method of seasonal evapotranspiration coefficient and evapotranspiration intensity (Ref. to table IV-13 and table IV-27) c) Adopting the combination method of evapotranspiration ratio and evapotranspiration intensity, under the conditions of paddy field having a higher level of expected yield (Ref. to table IV-23 and table IV-27). d) Applying the k-values calculated by Blaney-Criddle formula. only within the limits of the drought year having the pan evaporation of about 450mm during paddy field period as the design year (Ref. to table IV-32 or Fig. IV-22).

• Journal of Life Science
• /
• v.19 no.5
• /
• pp.581-586
• /
• 2009

Bell pepper plants (Capsicum annuum cv. Plenty) were grown under low night temperatures (LNT: day/night temperature of $28/13^{\circ}C$) and optimum night temperatures (ONT: day/night temperature of $28/20^{\circ}C$) in growth chambers. Pollen grains were collected from plants in the growth chamber and incubated at 10, 15, 20, 25, and $30^{\circ}C$. After 24 hr incubation, in both ONT and LNT, the highest percent pollen germinations were observed at $25^{\circ}C$ followed by germinations at $30^{\circ}C$. Percent pollen germination at $25^{\circ}C$ was 42% in ONT - two times higher than in LNT at 21%. Pollen tube length was much longer at ONT than at LNT, regardless of incubation temperature. Compared with other treatments, earlier and quicker pollen tube elongation was observed in ONT pollen grains incubated at $25^{\circ}C$. To find pollen viability in plant growing conditions, pollen grains were incubated in LNT ($28/13^{\circ}C$) and ONT ($28/20^{\circ}C$) growth chambers for 24 hr. Petri-dishes with pollen grains were put in the growth chambers at the beginning of the night condition. Pollen grains in the LNT growth chamber did not germinate at night ($13^{\circ}C$), but began to germinate when the day condition ($28^{\circ}C$) started. Pollen grains in the ONT condition, however, started germinating from the early night ($20^{\circ}C$) and germination continued during the day ($28^{\circ}C$). Plants in LNT showed increased flower stalk length, ovary diameter, stamen length, flower weight, and fruit length. LNT conditions did not impair seed set. There were no differences in seed sets between fruits at LNT and ONT. Normal seed sets in LNT show that fertilization may be completed during daytime. However, further investigation is needed to find what extent of temperature stress causes malformed and/or parthenocarpic fruits in this bell pepper.

• Korean Journal of Ichthyology
• /
• v.3 no.1
• /
• pp.1-10
• /
• 1991

Spawning behavior and development of eggs and larvae of Mugilogobius abei were observed in the laboratory at Pusan, Korea. The adult male of Mugilogobius abei was observed making nest-like spawning-bed to lay eggs and showing territorial and courtship behaviors. The eggs were transparent and spherical in shape, measuring 0.40~0.50 mm in diameter. They have a bundle of adhesive filaments at their basal end and a cluster of small oil globules. The eggs became ellipsoid shape after the insemination and measured about 0.93~0.96 mm on the long axis. Hatching began about 110 hours after fertilization at water temperature of $24.5{\sim}25.5^{\circ}C$. The newly hatched larvae were 2.04~2.10 mm in total length, with 24~25(8~9+16) myomeres. Many melanophore and guanophore are distributed on eye cups, gas bladder, optic vesicle and the caudal region. Four days after hatching the yolk and oil-globule were completely absorbed and the larvae attained a total length 2.20~2.35 mm. The larvae swam actively in the aquarium and start to practice feeding on the rotifer. Twelve days after hatching, the larvae averaged 3.20 mm in TL and the caudal notochord flex at $45^{\circ}$. Rudimental second dorsal, anal, caudal and ventral fins are also formed. The larvae attained 10.40~10.80 mm in TL, 35 days after hatching, are found to start the bottom-life after having completely formed first dorsal and ventral fins. The larvae reached the juvenile stage at 50~60 days after hatching and attained 15.37~20.25 mm in TL. At this period all scales appeared on the body.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.459-465
• /
• 2012

This study was conducted to obtain investigated characteristic factors which has an influence on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature. It was done by the carrot cultivation at black volcanic ashes soil in the experimental field of Jeju Special Self-governing Province Agricultural Research and Extension Services from 2010 to 2011. During the carrot cultivation period, the more amount of nitrogen fertilizer applied, the more amount of $N_2O$ emissions were released. Generally $N_2O$ emissions were so deeply released to climate as that in the first and middle of cultivation with heavy rainfall released amount is high, otherwise it was released very low at the end of cultivation and drought season. $N_2O$ emissions type was considered to relate with the rainfall pattern and soil water content. We obtained the result correlated with $N_2O$ emissions, in 2010, as the soil water and soil temperature were significant to $0.5718^{**}$ ($r$) and $0.4908^{**}$ ($r$) respectively, but soil EC was not significant to 0.2704 ($r$). In 2011, soil water was significant to $0.3394^*$ ($r$), but soil temperature and soil EC were not significant to 0.2138 ($r$) and 0.2462 ($r$) respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NH_4-N$) were not significant to 0.0575 ($r$) and 0.0787 ($r$) respectively. During the carrot cultivation period, the average emissions factor released by the nitrogen fertilizer application for 2 years was presumed to be 0.0025 $N_2O$-N kg / N kg. This factor was 4 times than the IPCC (0.0100 $N_2O$-N kg / N kg) factor.

• Korean Journal of Soil Science and Fertilizer
• /
• v.45 no.3
• /
• pp.451-458
• /
• 2012

This study was conducted to investigate the characteristic factors which have been influenced on nitrous oxide ($N_2O$) emissions related to the environment change of nitrogen application level, rainfall and temperature during the soybean cultivation at black volcanic ash soil from 2010 to 2011. During the soybean cultivation, the more amount of nitrogen fertilizer applied, $N_2O$ emissions amounts were released much. $N_2O$ emissions with the cultivation time were released much at the first and middle of cultivation with heavy rainfall, but it was released very low until the end of cultivation and drought season. $N_2O$ emissions mainly were influenced by the rainfall and soil water content. The correlation ($r$) with $N_2O$ emissions, soil water, soil temperature and soil EC in 2010 were very significant at $0.4591^{**}$, $0.6312^{**}$ and $0.3691^{**}$ respectively. In 2011, soil water was very significant at $0.4821^{**}$, but soil temperature and soil EC were not significant at 0.1646 and 0.1543 respectively. Also, $NO_3$-N and soil nitrogen ($NO_3-N+NO_4-N$) were very significant at $0.6902^{**}$ and $0.6277^*$ respectively, but $NO_4$-N was not significant at 0.1775. During the soybean cultivation, the average emissions factor of 2 years released by the nitrogen fertilizer application was presumed to be 0.0202 ($N_2O$-N kg $N^{-1}\;kg^{-1}$). This factor was higher about 2.8 and 2 times than the Japan's (0.0073 $N_2O$-N kg $N^{-1}\;kg^{-1}$) value and 2006 IPCC guideline default value (0.0100 $N_2O$-N kg $N^{-1}\;kg^{-1}$) respectively.

• Journal of Embryo Transfer
• /
• v.19 no.2
• /
• pp.155-163
• /
• 2004

The aims of this study are 1) to test oocytes and embryos collected from in-vitro to achieving the valuable protocol by culturing, vitrifying and thawing of oocytes/embryos, and 2) to transfer them to recipient, and finally have resulted in pregnancies from recipient females after surgical or nonsurgical transfer. In vitro maturation and fertilization were performed according to Funahashi et al (1994). Glucose-free NCSU 23 supplemented with 5 mM sodium pyruvate, 0.5 mM sodium lactate and 4 mg/ml bovine serum albumin for 2 days at $39^{\circ}C$, and 10% fetal bovine serum albumin was added to the culture medium thereafter. Embryos were treated with 7.5 ${\mu}g/ml$ cytochalasin-B for 30 min, centrifuged at 13,000 rpm for 13 min and then exposed sequentially to an ethylene glycol(EG) vitrification solution, aspirated into OPS, and plunged/thawed into/from liquid nitrogen. In vivo embryos were surgically collected from three dornors after AI for control group. Forty-nine embryos were washed 3 times in mPBS + 10% FBS, followed treatments : cultured, centrifuged, vitrified, recovered and transferred to recipients as in vitro prepared embryos. Three recipients were transferred individually with 100, 100 frozen embryos derived from abattoir and 34 fresh embryos by surgically, and another three recipients were transferred individually with 150, 150 frozen embryos and 100 fresh embryos by nonsurgically, respectively. all recipient sows exhibited delayed returns to estrus. To our knowledge, theses results suggest that required an improved techniques, more vigorous embryos preparation and substitute to gilt with cleaner uterous condition.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.47 no.6
• /
• pp.479-485
• /
• 2002

This study was conducted in order to elucidate the effects of nitrogen level and split application method, and shading treatment during reproductive stage on sink formation. Japonica variety Choocheongbyeo and Hwaseongbyeo and indica$\times$japonica cross type variety Nampoongbyeo were used. Five levels (6 to 30 kg/10a at 6 kg/10a interval) of nitrogen fertilization, and two split application methods (50-25-25% and 30-30-40% as basaltillering-panicle fertilizer) for each nitrogen treatment were applied. In addition shading treatments (shading rate, 65%) were performed for N 12 kg/10a and 24 kg/10a plot. Shading were applied for 30 days from panicle initiation to heading, 15 days from panicle initiation and 15days before heading. Panicle per square meter, and primary rachis branches per panicle and differentiated number of secondary branch per panicle increased according as applied nitrogen amount increased up to 18 to 24 kg/10a, and there was no significant difference between two nitrogen application methods. Primary rachis branch and secondary branch per square meter also increased according as the amount of applied nitrogen increase up to 18 to 24 kg/10a, and there was no significant difference between nitrogen application methods. Panicle per square meter and primary rachis branch per panicle were significantly decreased due to shading treatments only in Choochengbyeo. In all varieties, shading reduced secondary rachis branch per panicle significantly and the reduction was greatest in 30 days shading during reproductive stage. Spikelets per square meter increased according as the amount of applied nitrogen increases up to 18 to 24kg/10a, but showed no move increase above this nitrogen application level. Significant difference was not shown between nitrogen split methods. Spikelets per square meter also decreased significantly due to shading treatment during reproductive stage, showing the greatest reduction by 30 days shading during reproductive stage, and the least by 15 days shading during booting stage. The variation of spikelets per square meter was influenced greatest by the variation of panicles per square meter and spikelets per secondary rachis branch.