• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.6
• /
• pp.523-526
• /
• 2006

When $GA_{4}$ was applied to heading stage, it was examined to understand the change of plant hormones and starch during grain filling and ripening. Exogenous gibberellin caused a dramatic decrease in endogenous ABA content. Endogenous $GA_{4}$ content in both superior and inferior part was more promoted in $GA_{4}-treated$ rice grain than in the control. $GA_{1}$ content of an inferior part was not detected in the control and $GA_{4}-treated$ rice otherwise $GA_{4}$ was detected in all grain parts. Ripened grain rate in $GA_{4}-treated$ rice grain was lower than that of the control plant. Amylopectin from $GA_{4}-treated$ grain contained more very short chains with degree of polymerization (DP) between 4 and 8 than amylopectin from the control plant. It suggests strongly that fine structure of rice endosperm may be changed by exogenously applied $GA_{4}$ in rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.58 no.2
• /
• pp.107-112
• /
• 2013

The aim of this study was to test hypothesis that low sink size could mitigate deterioration of grain filling characteristics under high grain filling temperature. To achieve this aim, we selected Donganbyeo as a tolerant and Ilpumbyeo as susceptible variety to high temperature during grain filling period through screening 6 rice varieties. Then their spikelets number and the ratio of superior and inferior spikelet were compared. Grain weight and head rice ratio of Ilpumbyeo decreased significantly in high temperature. Ilpumbyeo had more spikelets than Donganbyeo. However, there was no significant difference between two varieties in the ratio of superior and inferior spikelets. So we tried to investigate the varietal difference of grain filling characteristics with removing inferior spikelets. Removing inferior spikelet in both of varieties could recover grain weight but not improve head rice ratio under high temperature. These results showed that sink/source ratio affected grain weight but didn't affect head rice ratio. Therefore, new approach was required to improve head rice ratio beyond sink/source ratio under high temperature.

• Proceedings of the KWS Conference
• /
• 2006.10a
• /
• pp.123-124
• /
• 2006

This study aimed at exploiting low heat input characteristic of laser welding to effectively control grain coarsening in the fusion zone(FZ) and heat affected zone(HAZ) of 1.5mm thick 18wt% Cr ferritic stainless steel weld. The study demonstrated that as compared with gas tungsten arc welding(GTAW), laser welding brought about significant grain refinement in the FZ and HAZ. However, the impact absorbed energy of GTA weld was superior than that of laser weld because the strengthening effect during welding and cooling stage was higher In laser weld than that in GTA weld. The coarser grains in each weld than base metal resulted in an inferior toughness.

• Journal of Korea Foundry Society
• /
• v.17 no.5
• /
• pp.494-501
• /
• 1997

In order to manufacture large rod preforms of 2014 Al alloy with a good mechanical property by spray forming method, it was spray-formed at a droplet temperature of $715^{\circ}C$, a droplet flight distance of 400mm, and a spraying angle of $35^{\circ}$. The rod preforms were extruded at $397^{\circ}C$ with the die temperature of $420^{\circ}C$ under the hot extrusion ratio 21:1 and T6 heat treatment was performed. The 2014 Al alloys cast by hot top process were also extruded and heat-treated at the same condition as a reference material. Microstructural observation and tensile test were carried out to investigate the effects of extrusion on microstructure and mechanical property of spray-formed Al alloy. Spray-formed Al alloys had many porosities due to inappropriate process conditions such as long droplet flight distance and low droplet temperature but have fine equiaxed grain. These porosities were reduced with decreasing in grain size by hot extrusion. Ultimate tensile strength and yield strength of spray formed-extruded 2014 Al alloy were inferior to those of the normal cast-extruded 2014 Al alloy, but elongations were superior. The control of porosity was important to get spray formed preform with a good mechanical property.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.30 no.4
• /
• pp.460-470
• /
• 1985

Experiments were carried out to evaluate the standard gravity in determining potential kernel size and to determine the effective sampling way by analyzing intra - and inter - plant variations for some source and sink characters using eleven semi-dwarf indica and three japonica cultivars including four semi-dwarf indica nearisogenic lines. Also, additional experiments were conducted to understand yearly variation and variety x year interaction effects for ten characters related to source and sink and to characterize the varietal difference of pre- and post-heading self-competition employing three parental varieties and their F$\sub$5/ progenies in 1982 and 1983. It is desirable to determine the potential kernel size by average kernel wight of rice grains showing above 1.15 specific gravity. There was significant difference in leaf area per tiller, spikelets and sink capacity per panicle among vigorous, intermediate and inferior tillers classified by differentiated order and vigorousness. Although it was difficult to find out any significant difference in grain-fill ratio, ratio of perfectly ripened grain, potential kernel size and sink/source ratio between vigorous and intermediate tillers, there was big difference between them and inferior one. The coefficients of variation within each tiller-group for some characters related to source and sink were larger with the order of vigorous tillers < intermediate one '||'&'||'lt; inferior one, and the average heritability of all characters, evaluated by the ratio of varietal variance (equation omitted) to total variance (equation omitted), were higher with the order of inferior tillers '||'&'||'lt; intemediate one '||'&'||'lt; superior one. Therefore, it is desirable to sample the vigorous tillers to represent the varietal difference of these traits. '82-'83 year variations of three parental cultivars were significant for all traits except for leaf area/tiller, panicles/hill, leaf area index and rough rice yield. The characters showing highly significant variance of variety x year interaction were growth duration from transplanting to heading, leaf area/tiller, sink/source ratio, sink capacity/panicle and grain yield. Generalized yearly response of three parental varieties (Suweon 264, Raegyeong, IR1317-70-l) and their F$\sub$5/ progenies on the 1st and 2nd principal components extracted from ten source and sink characters generally exhibited reduction in both source and sink. However, there were diverse variety x year interactions such as progenies showing similar reaction with their parents and intermediate or recombinational yearly response with little or considerable yearly movement on the four-dimensional planes of the two upper principal components between 1982 and 1983. Sink characters revealing highly significant border effect were grain-fill ratio, spikelets and sink capacity per panicle. Among them the latter two especially showed significant variety x border effect interaction. Self-competition characterized by relative weakness of inside plant's sink characters compared to the border one was more severe during the reproductive stage before heading than maturing stage. Though the larger sink capacity per panicle generally disclosed the severer self-competition, some lines (like Suweon 264) revealed severe self-competition with small sink capacity while a few others showed tender self-competition in spite of big sink capacity per panicle.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.57 no.3
• /
• pp.219-225
• /
• 2012

Seed size has been considered as an effective criteria for selection of the most vigorous seeds in sorghum [(Sorghum bicolor (L) Moench]. The smaller seeds were inferior to the larger sizes in emergence and grain yield. This study was conducted to determine germination rate, field emergence and vigor of sorghum for selection of high quality seed by different seed size. Sorghum cultivar of two (Hwanggeumchal and Tojong) were separated into five seed size proportion (<2.36, 2.80, 3.15, 3.35 and >3.55 mm diam.) according to seed size. The larger seed was more higher 1,000 seeds weight, seed density, carbohydrates and protein content. Total seed germination performing varied 92% at the largest size (>3.55 mm diam.) frequently inferior to slightly 67% at smaller seed (2.36 to 2.80 mm diam.) in the standard germination test. Seed size did have a significant effect on mean emergence time (MET) and maximum emergence rate index (ERI) and percentage of emergence. It should be noted that the results refer to MET of sorghum seeds ranging from 4.26 to 4.74 days. The relationship of seed size was not only to stand establishment but to grain yield. Yield was most affected by seed size and large seeds were superior to the smaller seed in 25~37% of the cases. Especially, yield was significant under 3.15 mm the beginning.

• Journal of Veterinary Clinics
• /
• v.9 no.2
• /
• pp.407-416
• /
• 1992

This experiment was conducted to investigate the feed value of dried aloe leaf meal and the changes of blood values in growing pigs A total of 48 three crossbred pig(Landrace${\times}$Yorkshire${\times}$Hampshire) weighing average 25kg initially were randomly distributed into 12 groups of 4 heads(2 females and 2 males) each There groups were alloted on one of the following 3 dietary treatment : non-supplumented diet (control group), diet supplemented with 3% of dried aloe leaf meal(Aloe 3% group), diet supplemented with 6% dried aloe leaf meal(Aloe 6% group). The results obstained in feeding trial for 6 weeks and analysis of blood were summarized as follows : 1. In the chemical composition of dried aloe leaf meal contents of crude protein and crude ash were 9.43% and 15.10%, respectively. Amino acid composition was also inferior to other grain and bran feeds. 2. Daily gain of control, Aloe 3% and 6% groups were 740.5, 658.1 and 197.1 g respectively. Three were significant difference in daily gain among groups( p<0.05) and tended to be decreased with increasing levels of dried aloe leaf meal. 3. Daily feed intake of control, Aloe 3% and Aloe 6% groups were 1,960.5, 1,737.0 and 1,123.0 g, respectively. There were significant differences in daily feed intake among treatments(p<0.05) and tended to be decreased with increasing levels of dried aloe leaf meal. 4. Feed efficiency of control, Aloe 3% and Aloe 6% groups were 2.72, 2.63 and 5.70 respectively. Feed efficiency for pig fed diet supplemented with 3% of dried aloe leaf meal was a little superior to control, although no statistical difference was obstained between two treatments. 5. The digestibilities of dry matter, crude protein, nitrogen free extract and extract were significantly (p<0.05) higher for control group than for Aloe 3% and Aloe 6% groups. But there were no significant differences in digestibility of crude fat and crude fiber between control and Aloe 3% groups. 6. There were no difference between aloe leaf meal administrated groups and control group in blood picture and serum chemistry.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.59 no.1
• /
• pp.59-65
• /
• 2014

As for Ethephon treatment, the heading stage is 2 days later at the concentration of 250 ppm and 500 ppm for the booting stage that when there is no treatment, 4 days later at the concentration of 1000 or more ppm but no difference for the blossoming and ripening stage. The culm length get shorter as the concentration of Ethephon is higher and the rate of culm length damaged is 37% for 1500 ppm of booting stage, which is the most effective processing, and the inferior culm length damage rate is bigger than the superior culm length damage rate. There is no difference between the number of glumous flower, culm and litter weight and the non-processing and as for the thousand grain weight, it is slightly bigger than when there is not any processing. The rate of germination is indifferent, the number of seeds get numerous regardless of the concentration of treatment and the number augments by 5% maximum for the booting stage. The number of days it takes from treatment of desiccant to the moisture content for harvesting time is respectively 15 days for seeds of 30 day-treatment, 10 days for seeds of 35 days-treatment and 5 days for seeds of 40 to 45 day-treatment. As for the harvest time after treatment of desiccant, the treatment at $30^{th}$ days and $35^{th}$ after the earing is 8 days earlier than the culture by conventional methods, 8 days earlier for the treatment at $40^{th}$ day. When the desiccant treatment is implemented, the thousand grain weight is heavier as the number of days of treatment gets later. The rate of germination gets higher as the number of days of treatment after earing gets later but there is no statistically significant difference 35 days after the earing. Yields are 37% compared to the culture by conventional methods for the treatment of 30 days after the earing, 70% compared to the culture by conventional methods for the treatment of 35 days after the earing, and 92% compared to the culture by conventional methods for the treatment of 40 days after the earing. The treatment before the physiological maturity impacts greatly upon the quality of seeds.