• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.22 no.1
• /
• pp.52-60
• /
• 1977

The affect of annual weeds to rice yield with morphological characteristics was evaluated. Rice heading date was shortened 1～5 days and rice culm length was shortened 5～10cm in heavy weed growing condition. No. of grains per panicle and no. of panicle per hill were the major yield components in yield reduction.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.31 no.1
• /
• pp.112-119
• /
• 1986

The variations of antibiosis to whitebacked planthopper (Sogatella furcifera Horvath) in resistant varieties, N 22 (Wbph 1) and ARC 10239 (Wbph 2) was investigated at different seedling ages and different tillers within a plant. The antibiosis of the rice plants to the insect was measured as the nymphal survival rate on the rice plants. The survival rate of the WBPH on N 22 was greater than on ARC 10239. It was also different at different seedling ages and the tillers within a plant with different tendency of two resistant rice genotypes, N 22 and ARC 10239. NO significant differences of nymphal survival rate was found between 7 and 30 days old seedlings on N 22, and greatly reduced on the 60 days old seedling. On the other hand it was increased up to on 30 days old seedlings and gradually decreased from on 40 days old seedlings of ARC 10239. The nymphal survival rate was greater in tillers than in the main culm of the rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.21 no.1
• /
• pp.82-86
• /
• 1976

'Radiation No. 6' the first mutant variety of naked barley in Korea was developed from Bangju as .a mother variety. The new variety was characterized by early maturity, short-culm and stablized high yield by the increased number of spikes. 'Radiation No. 6' was registered as a leading variety in 1974, .after 7 years since induction of mutation started.of mutation started.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.27 no.2
• /
• pp.111-115
• /
• 1982

The trials were carried out for improvement of early maturing wheat varieties, desease resistant and good quality through transfering good characters of barley to the wheat, during 1980-'81. For these purpose, Chinese Spring, a wheat variety was used as male and Manker 16 a barley variety, as female parents. EACA($\varepsilon$-Amino Caprolic Acid) known as an inhibitor of blood coagulation was injected to all barley from 14 days until heading with 1$m\ell$ per culm at the level of 500ppM. $GA_3$ solution which accelerates pollen activity was also used with 75ppM concentration after pollination for two days including check to determine the single effect of EACA. Two different methods of the cross were used. One was bud-pollination, another was post-pollination. The result indicated that the post-pollination was better than bud-pollination in terms of pollination rate, even though formation rate of normal embryo was seemingly adversed. The new plant derived from barley-wheat cross was similar in phenotype to the wheat.

• Journal of the Korean Wood Science and Technology
• /
• v.51 no.4
• /
• pp.309-319
• /
• 2023

Bamboo culm is in the form of a tube/pipe, composed of internodes which are bounded by a partition/diaphragm (node). Anatomically, bamboo is composed of vascular bundles and parenchyma ground tissue. One of the constituents of vascular bundles is fibers that are grouped to form a fiber sheath. The anatomical structure of the nodes and internodes is thought to influence the strength of bamboo strips, including tensile strength. This study aimed to determine the characteristics of vascular bundles (distribution and fiber percentage) and their effects on the density and tensile strength of Gigantochloa apus bamboo strips with and without nodes. The bamboo culms were divided into three parts (outer, middle, and inner) along the radial direction. The results showed that the distribution of vascular bundles and percentage of fiber sheaths decreased significantly from the outer to the inner layer. This also had a significantly decreased density and tensile strength. Furthermore, the number of vascular bundles (in the transverse plane) was greater in the internodes than in the nodes. Anatomically, the orientation of the vascular bundles at irregular nodes is observed in the radial and tangential planes, where the direction is not only in the axial direction, but also in the radial and tangential directions. This caused the tensile strength of the G. apus bamboo strips to be lower at the nodes than at the internodes.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.124-124
• /
• 2022

Wheat (Triticum aestivum L.) is the major staple foods and is in increasing demand in the world. The elevated temperature due to changes in climate and environmental conditions is a major factor affecting wheat development and grain quality. The optimal temperature range for winter wheat is between 15~25℃, it is necessary to study the physiological characteristic of wheat according to the elevated temperature. This study presents the effect of elevated temperature on the yield and quality of two Korean bread wheat (Baekkang and Jokyoung) in a temperature gradient tunnel (TGT). Two bread wheat cultivars were grown in TGT at four different temperature conditions, i.e. TO control (near ambient temperature), T1 control+1℃, T2 control+2℃, T3 control+3℃. The period from sowing to heading stage has accelerated, while the growth properties including culm length, spike length and number of spike, have not changed by elevated temperature. On the contrary, the number of grains per spike and grain yield was reduced under T3 condition compared with that of control condition. In addition, the. The grain filling rate and grain maturity also accelerated by elevated temperature (T3). The elevating temperature has led to increasing protein and gluten contents, whereas causing reduction of total starch contents. These results are consistent with reduced expression of starch synthesis genes and increased gliadin synthesis or gluten metabolism genes during late grain filling period. Taken together, our results suggest that the elevated temperature (T3) leads to reduction in grain yield regulating number of grains/spike, whereas increasing the gluten content by regulating the expression of starch and gliadin-related genes or gluten metabolism process genes expression. Our results should be provide a useful physiological information for the heat stress response of wheat.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.252-252
• /
• 2022

Genotype-by-environment interaction (GEI) refers to the comparative response of genotypes to different environments conditions. Thus, understanding GEI is a fundamental component for selecting superior genotypes for breeding programs. The significance of utilizing early maturing cultivars not only provides flexibility in planting dates, but also serves as an effective strategy to reduce methane emission from the paddy fields. In this study, we conducted multi-environment trials (METs) to evaluate yield-related traits such as culm length, panicle length, panicle number, spikelet per plant, and thousand grain weight. A total of eighty-one Korean commercial rice cultivars categorized as early maturing cultivars, were cultivated in three regions, two planting seasons for two years. The genotype main effect plus genotype-by-environment interaction (GGE) biplot analysis of yield-related traits and grain yield explained 70.02-91.24% of genotype plus GEI variation, and exhibited various patterns of mega-environment delineation, discriminating ability, representativeness, and genotype rankings across the planting seasons and environments. Moreover, simultaneous selection using weighted average of absolute scores from the singular value decomposition (WAASB) and multi-trait stability index (MTSI) revealed six highly recommended genotypes with high stability and crop productivity. The winning genotypes under specific environment can be utilized as useful genetic materials to develop regional specialty cultivars, and recommended genotypes can be used as elite climate-resilient parents to improve yield-potential and reduce methane emission as part to accomplish carbon-neutrality.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.303-303
• /
• 2022

The purpose of this study was to evaluate agronomic characteristics and identify the useful traits to utilize the wheat genetic resources for breeding programs by understanding the phenotypic variation among germplasm through multivariate analysis. In this study, a total of 394 wheat accessions were characterized for 15 agronomic traits using the National Agrobiodiversity Center (NAC) descriptor list, of which 31 accessions from 6 species and 363 unidentified accession (Triticum spp.) available at the NAC, Rural Development Administration (RDA), Korea. Growth characteristics such as leaf width, culm length, spike length, spikelet length, solid stemmed, days to heading, days to maturity, grain-filing period, and also seed characteristics such as width, height, area, perimeter, circle, solidity, and germination percent were studied. Among the 15 agronomic characteristics, the germination percent showed the smallest variation between resources (CV = 0.4%), and the spikelet length (CV = 66.5%) showed the highest variation. A strong positive correlation was found between seed traits such as seed height and seed area (r = 0.90), seed height and seed perimeter (r = 0.87) and seed length and width (r = 0.80). Principal component analysis (PCA) was conducted and the first five principal components comprised 76.7% of the total variance. Among the first five PCs, PCI accounted for 28.5% and PC2 for 20.0%. Wheat resources (394) were classified into four clusters based on cluster analysis, consisting of 215 resources(I), 117 resources(II), 48 resources(III), and 14 resources(IV). Among the clusters, the resources belonging to Cluster III showed the lowest seed width, height, area, and perimeter characteristics compared to other clusters. The wheat resources belonging to cluster IV had small seed width and low germination percent, but took longer to form heads and mature than resources in other clusters. These results will serve as the basis for further genetic diversity studies, and important agronomic characteristics will be used for improving wheat, including developing high-yielding and resistant varieties to biotic and abiotic stresses via breeding programs.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2022.10a
• /
• pp.62-62
• /
• 2022

Among annual precipitation in Korea (1306.3 mm), 54% of it falls intensively in summer, and only about 12.4% falls in April and May, when the water requirement of wheat is the highest. Korean wheat also could be damaged by soil water excess stress as frozen soil thaws after winter (late Feb-Mar). This study was conducted to evaluate effect of soil water stress on yield and quality of Korean wheat cultivar 'Saegeumgang'. Soil water treatments consisted of 4 treatments; water excess treatment in tilling stage (3.23-3.30), drought treatment in ripening stage (Apr-Jun), irrigation treatment in ripening stage (5.10) and standard condition. There was no significant difference between the treatment conditions for culm length, and the number of spike number was the highest in the order of irrigation in the ripening period (951)> standard cultivation (876)> excess water treatment in the tilling stage (752)> drought treatment in the ripening stage (767/m²). Test weight and Thousand grain weight were 548g/L and 22. lg respectively, which were lower than other treatments, and there was no significant difference between the other treatments. Abortive grain was 5.4kg/10a which was lower than other treatment, and there was no significant difference between the other treatment than other treatments. In drought treatment, protein content was 11.9% which is the highest among all treatments, and SDS-sedimentation value was 27.2ml under drought treatment which was very low compared to other treatments. Therefore, wheat yield and spike number were decreased in excess water condition at tilling stage and drought condition at ripening stage. Furthermore, wheat quality became deteriorate in drought condition at ripening stage.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2020.08a
• /
• pp.48-48
• /
• 2020

Assessment of plant genetic resources is applicable when breeding improved plant caltivars. In Korea, early maturing wheat germplasm is anticipated for wheat-rice double-cropping. In this study, we assessed five agronomical traits including days of heading after sowing(HD), days of maturity after sowing(MD), culm length(CL), ear length(EL), and thousand grain weight(TW) of 500 wheat germplasms collected form 10 different countries (Mexico, the United States, Afghanistan, Ethiopia, India, Japan, China, Turkey, Pakistan and Portugal), and grown in Korea. Besides, the correlation between the agronomical traits was analyzed using XLSTAT softerware version 2019 (Addinsoft, NY, USA). The result showed wide-ranging maturity period. Among the entire population, 2 accessions (K256306/JPN/breeding line and K256328/JPN/breeding line) that matured early were identified. Furthermore, HD showed strong correlation with MD (r=0.684) and CL (r=0.610), and weak correlation with the rest two agronomical traits (EL and TW). Overall, the results of our study provides wide spectrum of prospects, and could be applicable to breed new wheat varieties with early maturity.