Chon-Sik Kang

Comprehensive identification of LMW-GS genes and their protein products in a common wheat variety

Although it is well known that low-molecular-weight glutenin subunits (LMW-GS) from wheat affect bread and noodle processing quality, the function of specific LMW-GS proteins remains unclear. It is important to find the genes that correspond to individual LMW-GS proteins in order to understand the functions of specific proteins. The objective of this study was to link LMW-GS genes and haplotypes characterized using well known Glu-A3, Glu-B3, and Glu-D3 gene-specific primers to their protein products in a single wheat variety. A total of 36 LMW-GS genes and pseudogenes were amplified from the Korean cultivar Keumkang. These include 11 Glu-3 gene haplotypes, two from the Glu-A3 locus, two from the Glu-B3 locus, and seven from the Glu-D3 locus. To establish relationships between gene haplotypes and their protein products, a glutenin protein fraction was separated by two-dimensional gel electrophoresis (2-DGE) and 17 protein spots were analyzed by N-terminal amino acid sequencing and tandem mass spectrometry (MS/MS). LMW-GS proteins were identified that corresponded to all Glu-3 gene haplotypes except the pseudogenes. This is the first report of the comprehensive characterization of LMW-GS genes and their corresponding proteins in a single wheat cultivar. Our approach will be useful to understand the contributions of individual LMW-GS to the end-use quality of flour.

Hydration and Pasting Properties of Oat (Avena sativa) Flour.

Three oat cultivars and one oat breeding line were evaluated for chemical, hydration and pasting properties. Protein, starch and β-glucan levels ranged 11.13∼14.37, 56.37∼64.86 and 3.44∼4.76%, respectively. The oat cultivars Daeyang and Seonyang contained higher β-glucan levels of 4.76 and 4.35%. The Daeyang variety had a higher water absorption index (WAI) of 2.83∼3.35 (g/g), but a lower water solubility index (WSI) of 8.67 ∼11.08%. Daeyang and Seonyang cultivars showed higher peak and trough viscosity, but lower breakdown and setback, indicating that they easily swell, and thus could possibly provide the desirable viscosity of an oat product. The β-glucan levels were correlated positively with WAI, peak and trough viscosity, and negatively to WSI, breakdown and setback viscosity.

Effects of different fertilization treatments on the physicochemical and noodle-making properties of Korean winter wheat cultivars

Changes in the quality of white salted noodles prepared with different types of Korean winter wheat were examined. Crude protein and amylose contents of various wheat cultivars ranged from 7.17 to 9.97 and 24.78 to 29.37%, respectively. The water holding capacities of Jokyung with base N-fertilizer (NF) and Keumkang with 40% increased NF compared with NF at the supplementary manuring (SM) were 95.70 and 70.69%, respectively. The dry gluten content of the Keumkang with 20% increased NF compared with SM at the panicle initiation stage (PS) was 12.5%, and the final viscosities of several cultivars with NF, PS, and SM did not differ. PS treatment increased the thickness of the noodle sheet, and the hardnesses of cooked noodles prepared using Goso, Baekjoong, Younbaek, and Keumkang wheat with PS or SM treatment were increased. The thickness was strongly positively correlated with dry gluten content (DG) and water binding in wet gluten. In order to improve the quality of fresh noodles, wheat flour prepared using Hojung, Goso, and Baekjoong cultivars under PS cultivation condition or wheat flour with higher protein content, DG contents, and WBG should be used.

Influence of amylose content on cooking time and textural properties of white salted noodles

White salted noodles were prepared from reconstituted flours of various amylose content to determine the effects of amylose content on noodle dough properties and texture of noodles cooked for optimum cooking time. With decrease of amylose content from 26.5 to 3. 0%, optimum water absorption of noodle dough increased from 39 to 49% and cooking time of noodles decreased from 16 to 7 min. Hardness of cooked noodles prepared from reconstituted flour consistently decreased with increase in proportion of waxy starch. Noodles less than 12.4% amylose content exhibited higher springiness and cohesiveness than noodles greater than 17.1% amylose content. Cohesiveness and springiness of noodles prepared with partial waxy starches, of which amylose content ranged from 16. 6 to 22. 7%, were comparable to those of noodles prepared from <12. 4% amylose content. Amylose content of starch was significantly correlated with hardness, springiness, and cohesiveness of cooked noodles prepared from reconstituted flours.

Allelic Variation of Rht-1, Vrn-1 and Ppd-1 in Korean Wheats and Its Effect on Agronomic Traits

The allelic variations at the Rht-1, Vrn-1 and Ppd-1 of 410 Korean wheat cultivars, including 111 Korean experimental lines, 238 Korean landraces and 61 North Korean collections, were investigated to provide the information of plant height and heading date and to elucidate the relationship between those traits and allelic variation of these genes because earliness is major consideration in Korean wheat production. All Korean wheats displayed vrn-A1 and Ppd-A1b alleles, while Rht-B1a, Rht-D1a, vrn-B1, Vrn-D1, Ppd-B1b and Ppd-D1a alleles were also predominantly found. Most Korean wheats carried both Rht-B1a and Rht-D1a alleles, both vrn-B1 and Vrn-D1 alleles, or both Ppd-B1b and Ppd-D1a alleles. The Rht-B1a, vrn-D1, Ppd-B1b and Ppd-D1b alleles were found to exhibit longer culm and spike length than their counterpart alleles. The Rht-B1a allele also showed longer spike length than Rht-B1b. Vrn-B1b and vrn-D1 alleles exhibited longer days to heading date than their counterpart alleles at the Vrn-B1 and Vrn-D1 loci. Lines carrying both Rht-B1b and Rht-D1b alleles displayed shorter culm and longer spike length and days to heading date than any other combination of alleles at the Rht-B1 and Rht-D1 loci. In contrast, lines carrying both Ppd-B1b and Ppd-D1b alleles exhibited longer culm and spike length than any other combination of alleles at the Ppd-B1 and Ppd-D1 loci.

Effects of agronomic characteristics and grain morphology on pre-harvest sprouting in Korean wheat cultivar.

Pre-harvest sprouting (PHS), which is the precocious germination of the grains in the spike before it is harvest, is the serious problem in the reduction of end-use quality in wheat. In this study, the relationships among PHS tolerance, agronomic and grain characteristics in Korean wheat cultivars were evaluated for two years to improve PHS tolerance in Korean wheat breeding programs. Grain characteristics including 1,000 grain weight and grain size (length, width and thickness), PHS tolerance conducted by the mist spray in the humid chamber (PHS-MS) and germination index (GI), and Agronomic traits including heading date, maturing date, culm length, awn length and the number of grain/spike, were significantly influence by genotype, year and the interaction between year and genotype, except in spike length, the number of spike/m 2 and test weight. PHS tolerance and GI were significantly correlated with 1,000-grain weight (r = 0.618, and r = 0.528, respectively) and length, width and thickness of grain, although no significant relationship between agronomic traits and PHS tolerance was found in Korean wheat cultivars. PHS-MS also showed positively correlated with GI value (r = 0.770, P < 0.001). White grain cultivars showed higher PHS-MS and GI values (61.86% and 0.58, respectively) than red grain cultivars (11.89% and 0.18, respectively). White grain cultivars also showed higher values in length, width and thickness of grain than red grain cultivars. Among red grain cultivars, Alchan, Goso, Suan and Sukang showed lower values in both PHS-MS and GI (< 2.63% and < 0.05, respectively) and these cultivars could be used to improve PHS tolerance in Korean wheat breeding programs.

Mineral Compositions of Korean Wheat Cultivars

Twenty-nine Korean wheat cultivars were analyzed for 8 important minerals (Cu, Fe, Mn, Zn, Ca, K, Mg and P) using Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). A hierarchical cluster analysis (HCA) was applied to classify wheat cultivars, which has a similarity in mineral compositions. The concentration ranges of the micro-minerals Cu, Fe, Mn, and Zn: 0.12~0.71 mg/100 g, 2.89~5.89 mg/100 g, 1.65~4.48 mg/100 g, and 2.58~6.68 mg/100 g, respectively. The content ranges of the macro-minerals Ca, K, Mg and P: 31.3~46.3 mg/100 g, 288.2~383.3 mg/100 g, 113.6~168.6 mg/100 g, and 286.2~416.5 mg/100 g, respectively. The HCA grouped 6 clusters from all wheat samples and a significant variance was observed in the mineral composition of each group. Among the 6 clusters, the second group was high in Fe and Ca, whereas the fourth group had high Cu, Mn and K concentrations; the fifth cluster was high in Zn, Mg and P. The variation in mineral compositions in Korean wheat cultivars can be used in the wheat breeding program to develop a new wheat cultivar with high mineral content, thus to improve the nutritional profile of wheat grains.

Effects of γ-irradiation on the quality changes of fresh noodles prepared from wheat cultivated with N-fertilization treatments

Quality changes of fresh noodles prepared from wheat cultivated with N-fertilization treatments, followed by γ-irradiation were investigated. The protein content of the KPS60 was the highest of all treated samples, and protein contents of wheat cultivated with N-fertilizer was increased. γ-Irradiation did not affect the protein contents of the samples. However, the water holding capacity and resistant starch contents was increased by irradiation. The dry gluten and wet gluten contents of samples were further increased by γ-irradiation. The pasting properties were influenced by γ-irradiation but not N-fertilization. The hardness of noodles made with irradiated wheat flour was decreased, but the degree of decrease was small compared with that of viscosity. The gumminess and chewiness of noodles made with irradiated flour having higher protein content and WG showed also higher score. Thus, treatment of wheat flour with N-fertilization and γ-irradiation may improve the quality of Korean-style noodles during storage.

The effects of Rht semi-dwarfing alleles on agronomic traits in Korean wheat cultivars

The allelic variation at Rht-B1, Rht-D1 and Rht8 loci of Korean wheat cultivars was determined to evaluate the relationship between agronomic traits and different Rht alleles. Korean wheat cultivars had high frequency of Rht-B1a (70.4%) and Rht-D1a (51.9%) alleles. Thirteen cultivars carried both Rht-B1a and Rht-D1b alleles but no cultivar carried both Rht-B1b and Rht-D1b alleles. Only two cultivars, Namhae and Ol, showed 206bp fragment and whereas remaining genotypes showed 196bp at Rht8 loci. Cultivars carrying Rht-D1a and Rht8196bp alleles exhibited higher thousand kernel weight and test weight (40.2g and 809.9g, respectively) as compared to their counterpart alleles (36.6g and 788.1g, respectively). Cultivars carrying Rht-B1a and Rht-D1a alleles showed lower number of kernels per spike than those with other alleles at Rht-B1 and Rht-D1 loci. Cultivars, Namhae and Ol, carrying Rht8206bp allele showed lower test weight regardless the allelic compositions at Rht-B1 and Rht-D1 loci. Significant differences were recorded in culm and spike length regardless of allelic variation of these semi-dwarf genes.

Effect of Film Layers and Storing Period on the Fermentation Quality of Whole Crop Barley Silage

Dept. Animal bio, Chanbuk National University, Jeonju, 561-756ABSTRACTThis study was undertaken to characterize feed value and silage quality according to storage period and film layers for whole-crop barley silage. The crude protein(CP) content increased in all silage during the storage periods compared to those before silage,this content slightly increased over the prolonged storage period but it was not significant(p>0.05). Depending on the film layers of silage, 6 layers were higher than 4 layers. The neutral detergent fiber(NDF) and acid detergent fiber(ADF) contents also increased in all silage during storage periods compared to those before silage(P<0.05), but they were maintained at similar levels during the storage period. Depending on the film layers of silage, 6 layers were higher than 4 layers. The total digestible nutrients(TDN) content decreased in all silage during the storage periods. However, it was maintained at a similar level for the duration of each storage period. Depending on the film layers of silage, 6 layers were lower than 4 layers. The pH value was decreased during the prolonged storage period and depending on the film layers, 6 layers were lower than 4 layers.In the organic acid contents during the prolonged storage period, lactic acid increased, acetic acid was lower, and butyric acid was significantly higher(p<0.05). Depending on the film layers, 6 layers showed higher levels of lactic acid and lower levels of butyric acid(p<0.05). Therefore, these results showed that 6 layer wrapping was advantageous for long term storage of whole crop barley silage, while also indicating that it is desirable to use 4 layer wrapping within a six month period.(Key words :Whole crop barley, Storing period, Film layers, Fermentation quality)