• Journal of the Korean Wood Science and Technology
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• v.52 no.4
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• pp.383-392
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• 2024

Laminated bamboo is an engineered bamboo technology to maintain its mechanical durability for both construction and furniture materials. This study was conducted to assess the properties of laminated bamboo made from Betung bamboo at different culm positions and laminate orientations. The materials used in this study were 4-year Betung bamboo (Dendrocalamus asper) obtained from a community forest in Yogyakarta and polyvinyl acetate resin as adhesive. Two factors were applied for this study, i.e., culm position (lower, middle, and upper) and laminate orientations (vertical and horizontal direction). To examine the mechanical properties, a static bending test and the hardness test were performed in accordance with ASTM D1037-99. Moisture content and density were determined in accordance with BS 373-1957. The results indicated that there was no interaction between the culm position and laminate orientation on the moisture content, density, static bending properties and hardness. The culm position affected the static bending and hardness, with the higher position of the culm resulting a greater strength. The laminate orientation also affected the strength of laminated bamboo, with the vertical direction resulting in higher strength than the horizontal.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.1
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• pp.123-130
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• 1996

Experiments were conducted to effect of seeding rates and growth regulator (KIM-112) application on lodging resistance and yield in direct seeding on flooded paddy surface. The number of seedlings per $m^2$ were ranged from 61 to 143, and seedling ratios were from 71.7 to 76.1％. The culm length was increased with the higher seeding rates. The culm length was significantly shortened by KIM-112 application, and the shortened effect of internodes were various with application times. The leaf angles with the culm and top leaves were errected and position of light reception by KIM-112 application, also the weight of culm base was increased. The bending moment at breaking of culm and culm diameter were decreased according to the higher seeding rates. The number of panicles per $m^2$ were increased according to the higher seeding rates. The ripened grain rate and 1, 000 grains weight became higher than the untreated control.

• Korean Journal of Agricultural Science
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• v.9 no.2
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• pp.569-575
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• 1982

Mechanical properties of rice plants were tested to determine compressive force, bending force, tensile force and shear force for improvement of harvesting machines and for efficient utilization of rice culm during the proper harvesting period. Rice varieties used in this study were two Japonica varieties with Irri 348 and Jinju, and two $Indica{\times}Japonica$ hybrids with Seogwang and Taebaeg, which were grown in the standard fertilization field of Chungnam Rural Development Office. Also Jinju and Taebaeg were tested to elucidate the shearing characteristics which included shear force-strain relationship, shear force and shear energy according to the position from the ground level, the shearing angle to the rice culm, and the moisture content. 1. Compressive force, bending force, tensile force and shear force were higher In Japonica varieties than $Indica{\times}Japonica$ hybrids. 2. Shear force to overall culm length decreased progressively to upper positions in Jinju variety but a constant shear force was approximately showed between the ground level and the position of 21cm in Taebaeg variety. 3. Shear force and shear energy increased with increase of the cross sectional area, and the rates of increase were high in general up to the cross sectional area of $10mm^2$ and then they became dull very much. 4. Shear force and shear energy decreased with decrease of moisture content of rice culm after cutting up to the moisture content of 60% (w. b.) and then they did not change significantly.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.5 no.1
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• pp.1-35
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• 1969

Attempts were made to obtain the fundamental knowledge on the quantitative constitution status of leaves and stem of elongating node-part, and the relationships between these morphological characteristics along with the nitrogen contents of leaves and grain yield were examined varing application amounts of nitrogen in rice plant. I. The agronomic characteristics of leaves and nodes of elongation node-part (4-node parts from the top of stem) were observed at heading stage with 20 leading rice varieties of Kang Won district. The results are summarized as follows: 1. Leaf area magnitude of the flag and the fourth leaf was smaller than that of the second and the third with the average value of flag leaf 18.61 $cm^2$, the second leaf 21.84 $cm^2$, the third 21.52 $cm^2$ and the fourth 18.56 $cm^2$. The weight of leaf blade showed an isotonic tendency with the magnitude of leaf area with the value of the flag leaf 97.0 mg, the second leaf 117.1 mg, the third 115.4 mg, and the fourth 95.3 mg. The weight of each leaf sheath was remarkably larger at the higher node-part than at the lower node-part of the stem with the value of flag leaf sheath 176.3 mg, the second 163.7 mg, the third 163.4 mg and the fourth 123.9 mg. Accordingly, the total leaf weight of each part was larger at the second and the third leaf than at the first and the fourth. Total plant weight of each part (weight of leaf blade, leaf sheath, and culm) also was larger at the middle node-part. 2. Coefficients of variation for the varietal differences of the morphological characteristics of elongating node-part were 12.75% for the leaf area, 15.29% for the weight of leaf blade, 15.90%, for the weight of leaf sheath, 11.42% for the weight of internode, 15.45% for the leaf weight (leaf blade ＆ leaf sheath) and 13.24% for the straw weight. And these coefficient values of the most characteristics were, on the whole, smaller at the second and the third node-part than at the first and the fourth node-part, but the coefficient value of the internode weight was rather small at the third and fourth node-part. 3. Constitutional ratio of each plant organ to the total plant weight in term of dry matter weight (excluding head and root wight) was 39.2% for the leaf sheath, 34.2% for the culm, 26.6% for the leaf blade. And ocnstitutional ratio of leaf sheath in term of dry matter weight was larger at the higher position in contrast with that of culm. 4. Average weight ration of leaf blade to culm, leaf sheath to culm, leaf blades to sheath and the leaf blades to culm plus leaf sheath were 77.7 %, 114.5%, 67.9% and 36.2%, respectively. With regard to the position of the plant organ, the weight ratio of leaf blade to culm and that of leaf sheath to culm were larger at higher part in contrast with that of leaf blade to leaf sheath. 5. Generally, there founded deep relationships between grain yield and each morphological characteristics of plant organ of elongating node-part as follows; Correlation coefficient between total area of 4 leaves (from flag to the fourth leaf) and grain yield was ${\gamma}$=0.666$^{**}$ In regard to the position of leaves, correlation coefficient values of flag, the second, the third and the fourth leaf were ${\gamma}$=0.659$^{**}$, ${\gamma}$=0.609$^{**}$, ${\gamma}$=0.464$^{*}$ and ${\gamma}$=0.523$^{*}$, respectively. Correlation coefficient between total weight of leaf blades and the grain yield was ${\gamma}$=0.678$^{**}$. In regard to the position of leaves, that of flag leaf was ${\gamma}$=0.691$^{**}$, and ${\gamma}$=0.654$^{**}$ for the second leaf, ${\gamma}$=0.570$^{**}$ for the third, and ${\gamma}$=0.544$^{**}$ for the fourth. Correlation between the weight of leaves (blade weight plus sheath weight) and the grain yield showed similar values. In the relationship between plant weight and grain yield there also was significant correlation, but with highly significant value only for the first node-part. There appeared correlation between total weight of leaf sheath and grain yield with the value of ${\gamma}$=0.572$^{**}$ and in regard to the position of each leaf sheath the values were ${\gamma}$=0.623$^{**}$ for the flag leaf, ${\gamma}$=0.486$^{**}$ for the second leaf, ${\gamma}$=0.513$^{**}$ for the third, ${\gamma}$=0.450$^{**}$ for the fourth. However, there was no significant correlation between culm weight and grain yield. 6. With respect to in gain yield, varietal differences in magnitude of leaf area, weight of leaf blade, leaf weight per unit area, weight of leaf sheath, culm weight, total leaf and stem weight were larger in the case of high yielding varieties and decreased in accordance with decreasing yield. And this tendency also was shown in the varietal differences of magnitude of each part. Variation in magnitude of each part for the leaf area, weight of leaf blade, culm weight was significantly small in high yielding varieties compared to low yielding varieties. 7. Plant constitutional ratio of each organ of the elongating node-part in term of weight magnitnde varied to som extent according to varieties indicating leaf blade 27.6%, leaf sheath 39.5%, culm 32.9% in the case of high yielding varieties, leaf blade 25.5%, leaf sheath 38.1%, culm 36.4% in the case of low yielding varieties, and medium yielding varieties showed intermadiate values. 8. Far higher values of the weight ration of leaf blade to culm and leaf sheath to culm were given to the high yielding varieties compared to low yielding varieties. And medium yielding varieties showed intermadiate values. II. Effects of application rate of nitrogen on the morphological characteristics of the elongating node-part, nitrogen content of leaf blade, and their relation with the grain yield of the rice were observed with 3 rice varieties; Shin No.2, Shirogane, and Jinheung varying application amounts of nitrogen as 8kg, 12kg and 16kg per 10 are. 1. As for the variation of morphological magnitude s affected by the amounts of nitrogen application, total leaf area (4 leaves from the flag leaf) increased to 16.5% at 12kg N plot, and about 30% at 16kg N polt compared to 8kg N plot and total weight of leaf blade also increased to similar extent, respectively, in contrast with weight of leaf sheath increasing 4.9% and 7.8%, respectively. However, the weight of culm decreased to 1.5% and 11.2%at the 12kg N plot and 16kg N plot, respectively, and these decreasing rate was noted at the nodes of lower part. 2. As for the verietal differences in variation of morphological magnitude as affected by the amount of nitrogen fertilization, leaf area coefficient value of variation of the total leaf area was 15.40% for Shin No. 2, 12.87% for Shirogane, and 10.99% for Jinheung. With respect to the position of nodes, the largest variation of leaf blade magnitude was observed at the fourth for Shin No. 2, the second for Shirogan, and flag leaf for Jinheung. And there also was an isotonic varietal difference in the weight of leaf blade. Variation in total culm weight showed varietal differences with the coefficient value of 7.72% for Shin No.2, 12.11% for Shirogane, and 0.94% for Jinheung. There also was varietal differences in the variation according to the position of nodes. 3. Variation of each elongating node-part related to the fertilization amount decreased with the increase of fertilization amount in the items of leaf area, weight of leaf sheath, culm weight, but weight of leaf sheath varied more at heavier fertilization than at others. 4. Constitutional ratio of each organ excluding head also varied with fertilization amount; constitutional ratio of leaf blade increased much with the increasing amount of fertilization in contrast with the response of culm eight. However, constitutional ration of the weight of leaf sheath was not much affected. 5. Lower value of the ration of leaf blade to culm was given to the 8kg N per 10 are plot, and the ratio of leaf blade to leaf sheath decreased with the increasing amount of fertilization in contrast with the increase in the ratio of leaf sheath to culm. however, the ration of leaf blade to culm plus leaf sheath decreased. 6. With the increase of nitrogen fertilization, leaf area, weight of leaf blade and leaf sheath increased. Accordingly, grin yield also increased to some extent. It was noted that culm weight was changed inversely to the changes in grain yield, but the degree of this variation varied with varietal characteristics. 7. Nitrogen content of leaves at heading and fruiting stage varied with the fertilization amount, and average nitrogen content of leaves of the varieties used 2.19%, 2.49% and 2.74% at the plot of 8kg N, and 12kg N and 16kg N per 10 are, respectively, at heading time, and 0.80%, 0.92% and 1.03% at each plot at fruiting stage. Thus, nitrogen content of leaves increased much with the increasing amount of fertilization, and higher value was given to the leaves on the higher position of elongating node-part. 8. There also was variation of nitrogen content of leaves in accordance with the varieties. However higher grain yield was obtained from the plants retaining higher nitrogen content in leaves at heading or fruiting stage.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.223-227
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• 2008

In rice, tillering is an important trait determining yield. To study tillering at the agricultural and molecular aspects, we have examined a spontaneous rice mutant that showed reduction in the number of culms. The mutant was derived from a $F^6$ line of the cross of Junambyeo*4 / IR72. It could produce, on average, 4 tillers per hill in the paddy field while wild-type plants usually have 15. Except the reduced culm numbers, they also show pale green phenotypes. The phenotypes of this mutant were co-segregated as the monogenic Mendelian ratio (${\chi}^b=0.002$, p=0.969). In order to locate a gene responsible for the rcn phenotype, the mutant with the japonica genetic background was crossed with Milyang21 of the indica background. Bulked segregant analysis was used for rapid determination of chromosomal location. Three SSR markers (RM551, RM8213, and RM16467) on chromosome 4 were genetically associated with the mutant phenotype. Each of the 217 $F_2$ plants was genotyped with simple sequence length polymorphisms. The data showed that RM16572 on chromosome 4 was the closest marker that showed perfect co-segregation among the $F_2$ population. We suggest the new rcn gene studied here name as $rcn10^t$ because there was no report which exhibit a rcn phenotype with a pleiotropic effect of pale green (chlorophyll deficiency), and mapped at same position on chromosome 4.

• Korean Journal of Medicinal Crop Science
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• v.12 no.3
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• pp.219-225
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• 2004

This study was conducted to evaluate growth and yield characteristics and the contribution to the yield according to the emergent sequence of tiller under two planting density $(60{\times}15\;cm,\;60{\times}25\;cm)$ in Coix lachryma-jobi L. var. mayuen Stapf. The average culm length and number of rachillas of $60{\times}25\;cm$ planting density were 20 cm shorter and 4.7 higher, respectively, whereas seed setting position of $60{\times}25\;cm$ planting density was 1.7 nodes lower compared with $60{\times}15\;cm$ planting density. Culm length and culm diameter of each tiller became shorter and thinner as the tiller emerged later. Length of rachillas was longer, number of grains was higher and ripening rate was also higher in $60{\times}25\;cm$ planting density than those of $60{\times}15\;cm$ planting density, whereas 100 grain weight in $60{\times}25\;cm$ planting density was lower by 0.5 g compared with $60{\times}15\;cm$ planting density. Length of rachillas and number of grains according to the emergent sequence of tiller were shown shorter and lower as the tiller emerged later. The highest number of bract was obtained from the main culm in both planting densities. 100 grain weight according to the emergent sequence of tiller became lower as the tiller emerged later in $60{\times}15\;cm$ planting density, but there was no clear tendency in $60{\times}25\;cm$ planting density. Among 8 tillers, 5th tiller and 4th tiller of main culm contributed 84.4% to the yield in $60{\times}15\;cm$ planting density, while it was 84.1% in $60{\times}25\;cm$ planting density. Analysis of path coefficient to grain yield showed that direct effect was the highest in the number of grain per tiller followed by in the 100 grain weight and in ripening rate.

• Korean Journal of Medicinal Crop Science
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• v.12 no.4
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• pp.279-284
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• 2004

This experiment was conducted to evaluate on agronomic traits of Korean local adlay (Coix lachryma L.) germplasm, 281 cultivars (lines). The largest collected cultivars was from Kyungsangbukdo (56 cultivars), and the next was in the order of Cheonlabukdo (48 cultivars), Kyungsangnamdo (44 cultivars), Kyunggido (39 cultivars) Chungcheongnamdo (23 cultivars), Kangwondo (23 cultivars), Cheonlanamdo (17 cultivars), and Chungcheongbukdo (16 cultivars) in distribution of collected region for 281 cultivars. In the growth stages, days to emergence from seeding were required $16.4{\pm}2.03$ days, days to heading from emergence was required $73.6{\pm}5.87$ days, days to ripening from heading was required $52.3{\pm}4.91$ days and cultivation period was required $142.5{\pm}5.87$ days. Culm length was $210.3{\pm}16.39$ cm, no. of tiller per plant was $10.4{\pm}2.13$, culm diameter was $11.7{\pm}1.09$ mm, fruiting position was $4.6{\pm}0.82$ node, no. of main culm node was $11.1{\pm}0.78$, degree of lodging was $5.3{\pm}3.42$ and severity of leaf blight was $56.1{\pm}0.78$ in the growth characteristics of the germplasm. In the yield of component, no. of grains per $m^2$ was $5,938{\pm}2,152$, percentage of ripening was $67.7{\pm}33.12$, 1,000 grains weight was $123.8{\pm}33.76$ g and grain weight was $473.0{\pm}207.90$ g. Grain weight was correlates significantly positively with no. of main culm node, percentage of ripening and no. of grains per $m^2$ among agronomic traits. Correlation coefficient between grain weight and 1,000 grain weight was positive, while grain weight and severity of leaf blight was significantly negative. Correlation coefficient between grain weight and days to ripening from heading was significant negatively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.3
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• pp.155-163
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• 2022

The tillering potential of panicle number type (PNT) rice greatly varies with planting density. Moreover, grain filling and ripening differ depending on the panicle position, which may further affect rice grain quality. The present study evaluated the grain quality of PNT rice sparsely planted to reduce production costs. The physicochemical characteristics of starch from the grains of PNT type rice 'Ilpum' planted at different densities (37, 50, 60, and 80 plants/3.3 m²) and at different positions of panicles (upper or lower on the culm) were determined. Overall, as the planting density decreased, the number of panicles increased but the starch content decreased, which further reduced the 1,000-grain weight. In particular, at the lowest density (37 plants/3.3 m²), protein content increased but particle size, enthalpy, and relative crystallinity decreased. The effects were more pronounced at lower than at upper panicle positions. These findings indicate that tillering potential differs with planting density, ultimately affecting the palatability of rice grains. Based on these findings, we propose restricting rice transplantation to a planting density of ≤37 plants/3.3 m² to achieve the best quality of grains at lower costs and with less labor.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.533-538
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• 2004

An introgression line, WH79006 was produced from a single plant from $BC_5F_3$ families from a cross between Hwaseongbyeo used as a recurrent parent and O. minuta (BBCC, Ace. No. 101154) as a donor parent, which was subsequently self-pollinated for three generations. WH79006 resembled the O. sativa parent, Hwaseongbyeo. However it differed from Hwaseongbyeo in several traits including days to heading, culm length, grain size, spikelets per panicle and fertility. These differences in the traits between WH79006 and Hwaseongbyeo can be attributed to the O. minuta introgressions. To detect the introgressions, 294 SSR markers of known chromosomal position have been used. At least, 28 introgressed chromosomal segments have been identified using SSR markers and they map to all chromosomes except chromosome 2. The size of the introgressed segments ranged from 4 to 35cM. A QTL related to culm length was detected using 75 $F_2$ plants from the Hwaseongbyeo/WH79006 cross. This QTL, cl6 located on chromosome 6 explained $9.6\%$ of the total phenotypic variation in the population. This QTL has not been detected in the previous QTL studies between Oryza sativa cultivars, indicating potentially novel alleles from O. minutan.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.236-243
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• 2009

This study was conducted to develop a japonica-type rice cultivar with brown planthopper (BPH) resistance using DNA markers. A doubled haploid (DH) population consisting of 120 pure-lines was established by anther culture of $F_1$ hybrids between 'Samgang', a Tongil type BPH resistance cultivar, and 'Nagdong', a japonica cultivar. To determine the map position of genes responsible for BPH resistance in rice, a genetic map was constructed based on 120 DH lines. A total of 162 molecular markers were classified into 12 linkage groups, covering 1,884 Kosami centimorgan (cM) with an average of 11.6 cM. Five QTLs (qBPR3, qBPR6, qBPR7, qBPR8, and qBPR12) associated with BPH resistance were identified and mapped on chromosomes 3, 6, 7, 8, and 12, respectively, using the genetic map constructed in this study. To analyze the relationship between BPH resistance and agronomic traits, a total of eight QTLs related to the agronomic traits were detected on 12 rice chromosomes. In an analysis of relationships, three QTLs (qBPR3, qBPR7, and qBPR8) showed a linkage with tested agronomic traits. A QTL (qBPR3) located on chromosome 3 (RM282-3023) was closely linked to culm length (qCL3). The QTL (qBPR8) for BPH resistance on the short arm of chromosome 8 also overlapped the region detected in culm length (qCL8).