• Journal of Industrial Technology
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• v.20 no.B
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• pp.3-8
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• 2000

Low cycle fatigue life of spheroidal graphite cast iron is determined by the morphological parameters of internal graphite. The aim of this study is to clarify the effect of the number of nodular grain of spheroidal graphite cast iron on low cycle fatigue life. Two specimens that have identical average nodular grain size by changing nodular grain volume fraction and different number of nodular grain count was tested. In this paper, the parameter governing fatigue life through fatigue test, the number of nodular grain seriously affect fatigue life and nodular grain size is no longer governing parameter of it.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.234-234
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• 2017

Recent abnormal weather, especially continued rainfall during sowing season causes difficulty in proper sowing of wheat and delayed sowing after November 15 is concerned about freezing damage during winter, resulting in reduction of wheat yield. To correspond government policy of crop sufficiency improvement and produce and supply raw wheat and barley steadily, expansion of cultivation area is necessary and spring sowing of wheat is required. To obtain basic information on the improvement of spring sown wheat and barley production, comparison and path coefficients analysis was conducted for yield and yield related components from autumn and spring sown wheat and barley. Path analyses were known as very useful in clarifying the effects of yield components on grain yield formation, which were not accurately reflected in simple correlation anaylses. Most cultivated 5 wheat and 9 barley cultivars were sown on October and February at Cheon-ju province according to standard sowing method. For the spring sowing of wheat and barley, the varieties having vernalization degree I~III are seeded in the mid of February and seeding rate is 200~250kg/ha which is increased by 25% than autumn sowing. N-fertilizer of 95 kg/ha and the same amount of P, K dressed in autumn are applied at once as basal fertilizer. The magnitude of direct effect in each yield components on yield was in sequence as follows. In autumn wheat, grain number per $spike{\geq}$ the number of spike per $m^2$>1000-grain weight and in spring wheat, grain number per $ spike{\geq}the$ number of spike per $m^2$> 1000-grain weight. In autumn naked barley, 1000-grain weight> the number of spike per $m^2$, grain number per spike and in spring barely, the number of spike per $m^2$> grain number per spike > 1000-grain weight. In autumn covered barley, grain number per spike>the number of spike per $m^2$ and in spring coverd barley, the number of spike per $m^2$> grain number per spike, 1000-grain weight. In autumn malt barley, the number of spike per $m^2$>1000-grain weight and in spring malt barley, the direct effects of three yield components were similar. According to the path analysis of yield components for spring sown wheat and barley, it was suggested that adequate number of spike per $m^2$ was most important factor for yield increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.2
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• pp.120-126
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• 2003

Four different rice varieties, Sindongjinbyeo, Dongjin #1, Saegyehwabyeo, and Iksan 467, were transplanted under three different nitrogen levels and two different seedling numbers per hill to obtain basic information on panicle traits under different cultural conditions and to propose the ideal panicle structure in Japonica rice. Sindongjinbyeo and Iksan 467 were characterized by more primary rachis branches (PRBs) per panicle and more grains on PRB than other cultivars. The two varieties also had fewer secondary rachis branches (SRBs) per PRB and fewer grains on SRB per PRB. These characteristics, consequently, resulted in higher ripened grain rate, contrary to that of Dongjin #1 and Saegyehwabyeo. In the correlation coefficient analysis, PRB number per panicle and grain number on PRB per panicle were positively correlated with ripened grain rate, while SRB number per panicle, number of grains on SRB per panicle, SRB number per PRB, number of grains on SRB per PRB and grain number per panicle were negatively correlated with ripened grain rate. Therefore, the number of grains on PRB per panicle, SRB number per PRB and the number of grains on SRB per PRB were the appropriate criteria for determining and achieving higher ripened grain rate in rice. High ripened grain rate over 90% was obtainable with over 12.5 PRBs per panicle and 63 grains on PRB per panicle, and with under 1.7 SRBs per PRB, 5 grains on SRB per PRB, 130 grains per panicle, and 14 panicles per hill. The study recommended that for over 90% high ripened grain rate, the critical limiting factors should be under 2 SRBs per PRB, 6 grains per PRB, and 130 grains per panicle, irrespective of the PRB number per panicle and the number of grains on PRB.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.14
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• pp.41-45
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• 1973

This study was carried out in the central part of Korea in 1972 to investigate optimum grain number per square meter and variation of the yield and its components in the direct sowing culture on irrigated paddy field. The results could be summarized as follows; 1. Number of maximum tillerings was directly increased with increase of grain number from 120 to 280 per square meter and it was gradually decreased with increase of number sowing grain. So number of maximum tillerings showed at the plot of 280 grain per square meter. Also it was showed remarkable competition at the plot more than 280 grain per square meter. 2. Percentage of effective tiller was decreased with increase of number of sowing grain from 120 to 280 per square meter and after it was gradually decreased with increase of number of sowing grain. 3. It was not remarkable competition in plot less than 1, 000 tillering per square meter on the number of maximum tillerings. 4. It was remarkable positive correlation between the number of panicle and the number of sowing grain, but it was tendency to negative correlation between the number of panicle and the number of spiklets per panicle, and between the number of panicle and the ripening ratio. 5. Correlation coefficient between the yield and the number of spiklet per square meter of land area was 0.929, r=0.695 in the yield and the number of panicle, r=0.796 in the number of panicles and the number of spiklets per square meter Also in rank correlation, it was showed most highly positive correlation(r=0.954) between the yield and the number of panicles, so number of panicles was most largely dominated on yield among the yield components in direct sowing culture on irrigated paddy field. 6. It was producted highest yield in the plot of 280 grain sowing per square meter.

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.163-170
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• 2008

The detection, characterization and use of quantitative traits loci, QTL, have significant potential to improve the efficiency of selective breeding of species. Therefore, a population with 59 advanced backcross lines($BC_2F_5$), derived from a cross between IR64 and Tarome molaei, were studied in Tonekabon Rice Research Station of Iran in order to map QTLs for panicle length, number of grain per panicle, and panicle grain sterility in rice. The parental screening wtih 235 SSR markers in agarose and polyacrylamide gels revealed 114 markers with clear polymorphic bands. To search for QTLs associated with panicle length, number of grain per panicle, and panicle grain sterility, we constructed a genetic linkage map using 114 microsatellite markers. Positive and negative transgressive segregations were observed in $BC_2F_5$ lines for all traits. Using multiple interval mapping(MIM), a total of 20 putative QTLs were detected, of which eight were for panicle length, three for number of grains, and nine for panicle grain sterility. The maximum number of QTLs were mapped on chromosomes 1 and 2 with eight QTLs. These QTL markers could possible be utilized for marker-assisted selection.

• Journal of Life Science
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• v.7 no.1
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• pp.59-65
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• 1997

In this experiment, gene actions were analysized for seven barley parents in order to obtain basic information on their genetic improvement by diallel crosses. The results obtained were summarized as follows. In analysis of variance, additive, dominant, maternal and reciprocal effects were observed significantly for culm length, tiller number, number of spiked per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight. Over-dominance was shown by Vr-Wr graphic analysis in five characters such as tiller number, number of spikes per plant, length of flag leaf, number of grains per spike, and 1000 grain weight, and partial dominance in four characters such as culm length, culm diameter, awn length, and leaf width. Component of genetic varience analyzed for four characters such as culm diameter, awn length, length of flag leaf, and leaf width showed that additive effects were higher than dominant effects. Culm length, tiller number, number of spikes per plant, number of grains per spike, and 1000 grain weight showed dominant effects higher than additive effects. The narrow-sense heritability for awn length, leaf width, and number of grains per spike showed high values as more than 0.62, while broad-sense heritability for culm length, number of spikes per plant, culm diameter, awn length, leaf width, number of grains per spike, and 1000 grain weight showed high values as more than 0.65.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.8 no.1
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• pp.1-4
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• 1970

To study the varital response of grain, protein and oil yield to different sowing dates and calcium levels in soybean, the most important crop as a protein source in Korea, this experiment was conducted in 1969. Three leading soybean varieties (Choongbukbaek, Ryooku＃3 and Changdanbaekmok) were sown at May 22,, June 11 and July 1 under 3 different calcium levels, 0.50 and 100kg per 10a respectively. The results are summarized as follows: 1. Ryonku ＃3 showed the highest grain yield because of the highest number of pods per hill. In order of protein content, and oil content of grain, Choongbukbaek>Ryooku＃3>Changdanbaekmok and Changdanbaekmok>Choogbukbaek>Ryooku＃3 were found. Ryooku＃3 also showed the highest protein and oil production per unit area owing to the highest grain yield. However. varietal differences of the grain yield the protein and the oil production per unit area varied along the different sowing dates. Interactions between varieties and sowing date on the grain yield should be considered in practice. 2. No difference in the grain yield was found between the first sowing date (May22) and the second (June11) on average. The grain yield in the plot of the third sowing date (July l)was strikingly decreased mainly by the smaller number of pods per hill. The protein and the oil content were not varied significantly by the different sowing dates. The protein and oil production per unit area were lowest in the plot of the third sowing date owing to the decreased grain yield. 3. More calcium application increased the number of branches per hill, the number of pods per hill, and the grain yield. The highest grain yield was found in the plot received 100 kg of calcium hydroxide per 10are. Protein content increased in higher calcium level, but oil content was highest in the plot of noncalcium. More protein production per unit area was gotten by more calcium application because of higher grain yield and protein content. all production increased in higher calcium level by the increased grain yield. 4. High plus (+) correlation was found between stem length and stem weight per hill stem length and grain weight, stem length and grain yield, stem weight per hill and number of pods per hill and grain weight, number of branches per hill and grain weight, number of pods per hill and grain yield, and grain weight and protein content of grain. Minus(-) correlation was recognized between number of pods per hill and grain weight.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.1
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• pp.1-7
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• 2023

We studied the changes in growth characteristics of major cultivated rice in low- density transplanting. The culm and spikelet length did not change in low density transplanting conditions. As the distance between hills increased by 10 cm, the number of tillers per hill increased by an average of 4.4 and the number of grains per spikelet increased by 7.5. The cultivar that had more tillers and higher grain number in 80 hills per 3.3 m² tended to have more tillers and grain in low-density transplanting conditions. However, the increase rate of tillers and grain in low-density transplanting was not significanty different from the tiller and grain number in 80 hills per 3.3 m². The total branch number and branch length in spikelets increased in low-density transplanting conditions. The grain number per spikelet was also increased by the in low-density transplanting method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.15
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• pp.33-59
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• 1974

A series of experiments were conducted at Crop Experiment Station from 1968 to 1971 to obtain basic information on effects of selection on yield of wheat varieties. Heritability estimates, correlation and path coefficients computed for yield and yield related characters from fixed variety groups-Korean, U.S., and Japan; early and late-$F_2$ and $F_3$ generations were studied. The same estimates for fixed variety groups grown under different fertilizer levels and years were also studied. The results were summarized as follow: 1. Three variety groups classified by their origins as Korea, United States and Japan showed high heritability estimates for heading date, plant height and spike length. The heritability estimates for grain number per spike and 1, 000 grain weight were moderate and those for the number of spikes per plant and grain yield were low. Very low estimates of heritability were obtained for grain number per spike and yield of variety group from the Unites States. 2. High genotypic correlation coefficients between 1, 000 grain weight and yield were obtained for all variety groups originated from Korea, United States and Japan and early variety group, except late variety group. The genotypic correlation coefficients between grain number per spike and yield were also high for all variety groups except variety group originated from the United States. 3. The direct effects of 1, 000 grain weight in terms of path-coefficients to yield were high for all variety groups except late variety group. 4. High genotypic correlation coefficients were obtained between 1, 000 grain weight and yield in $F_2$ from. two crosses. The same degree of genotypic correlation coefficients were obtained between grain number per spike and yield, although slight differences in its magnitude were found depending upon the cross combination. 5. The analysis of path-coefficients in $F_2$ shows that the direct effects of yield components to yield were negligible. 6. The characters that showed high genotypic correlation coefficients with yield in $F_3$ were 1, 000 gnain weight and grain number per spike. These characters showed also high direct effects to yield. 7. No great variations of heritability estimates for heading date, plant height and spike length were obtained for either fertilizer responsive or non responsive variety group due to fertilizer levels applied. 8. Heritability estimates of 1, 000 grain weight in fertilizer responsive group and yield in fertilizer nonresponsive group were high as level of fertilizer increased. 9. Heritability estimates for grain number per spike and 1, 000 grain weight of fertilizer non-responsive-group were higher than those of fertilizer. responsive group. 10. Genotypic corretation coefficients between yield and 1, 000 grain weight in fertilizer responsive group were getting lower as the level of fertilizer increased and those in fertilizer non-responsive group were vice versa. 11. Genotypic correlation coefficient between yield and spike number per plant in fertilizer responsive group was high. However, the genotypic correlation coefficient between yield and spike number per plant in fertilizer non-responsive group was low. 12. The direct effects of 1, 000 grain weight to yield were higher than other yield components either in fertilizer responsive or non-responsive group regardless of levels of fertilizer applied. The spike number per plant, however, was high only when high level of fertilizers were applied to fitilizer responsive group. 13. Slight variations of heritability estimates for heading dates, plant height, spike length, grain number per spike and 1, 000 grain weight were obtained between years. However, the spike number per plant with low heritabilility showed great variation between years. 14. The character that showed high genotypic correlation coefficients with yield in two years was 1, 000 grain weight, and this character was also high in direct effect to yield in terms of path-coefficients. 15. From the above experimental results, it might be concluded that 1, 000 grain weight would be one of the most important characters to increase the effects of selection for yield in wheat breeding in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.2
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• pp.174-179
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• 1985

Estimate of heritabilities, genotypic and phenotypic correlations and path coefficient analysis were performed for the seven characters of barley cultivars (Hordeum vulgare L.). Heritabilities of broad sense for stem length and spike length were 0.923 and 0.907. Kernels per spike, grain yield and 100 grain weight also showed high heritabilities. High genotypic and phenotypic correlations existed between stem length and 100 grain weight. Grain yield showed highly significant phenotypic correlation with spike length, 100 grain weight and kernels per spike. Genotypic correlations between those characters were moderately high. Number of stem had greatest direct effect but the number of spike had a strong negative direct effect upon grain yield. Kernels per spike via number of spike showed greatest indirect effect and the number of stem via number of spike showed strong negative indirect effect upon grain yield.