• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.219-219
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• 2022

Granule-bound starch synthase I (GBSSI), encoded by the waxy gene, is responsible for the accumulation of amylose during the development of starch granules in rice endosperm. Despite many findings on waxy alleles, the genetic diversity and evolutionary studies are still not fully explored regarding their functional effects. Comprehensive evolutionary analyses were performed to investigate the genetic variations and relatedness of the GBSSI gene in 374 rice accessions composed of 54 wild accessions and 320 bred cultivars (temperate japonica, tropical japonica, indica, aus, aromatic, and admixture). GBSS1 coding regions were analyzed from a VCF file retrieved from whole-genome resequencing data, and eight haplotypes were identified in the GBSSI coding region of 320 bred cultivars. The genetic diversity indices revealed the most negative Tajima's D value in the tropical-japonica, followed by the aus and temperate-japonica, while Tajima's D values in indica were positive, indicating balancing selection. Diversity reduction was noticed in temperate japonica (0.0003) compared to the highest one (wild, 0.0044), illustrating their higher genetic differentiation by F_ST-value (0.604). The most positive Tajima's D value was observed in indica (0.5224), indicating the GBSSI gene domestication signature under balancing selection. In contrast, the lowest and negative Tajima's D value was found in tropical japonica (-0.5291), which might have experienced a positive selection and purified due to the excess of rare alleles. Overall, our study offers insights into haplotype diversity and evolutionary fingerprints of GBSSI. It ako provides genomic information to increase the starch content of cooked rice.

• Korean Journal of Agricultural Science
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• v.33 no.2
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• pp.149-157
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• 2006

The objective of this research was to know useful genetic characteristics for breeding program of corn. These materials were inbreds after selfing of six or eight generations and had useful genetic informations. The emergence of Danyang Waxy Corn was faster than those of other inbred lines at 2~3 days in field conditions. The plant height of Dangyang Waxy Corn was the highest at 8 days after emergence. However the plant height of New Dangjin was the shortest with 6.25cm at 8 days after emergence, the fresh weight of New Dangjin was 0.046g at 2 days after emergence but that of Dangyang was the heaviest with 0.180g. The fresh weight of 9 inbred lines had more increments in 2 days after emergence. The mean values of dry weight also showed similar trends in 9 inbred lines. The shoot dry weight of inbred lines, Dangyang and New Dangjin was 0.045g and 0.018g at 8 days after emergence, respectively. The root length of inbred line, Dangyang, was the longest with 64.4cm at 8 days after emergence. But the root length of New Dangjin was the shortest with 20.4cm at 8 days after emergence. The fresh weight of endosperm was 0.35g at 2 days after emergence and 0.26g at 8 days after emergence in Dangyang Waxy Corn, because of reduced nutrition of endosperm.

• Preventive Nutrition and Food Science
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• v.21 no.4
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• pp.393-397
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• 2016

Whole grain wheat flour (WGWF) is the entire grain (bran, endosperm, and germ) milled to make flour. The WGWF of 31 Korean wheat (Triticum aestivum L.) cultivars were analyzed for the chemical compositions, and classified into groups by hierarchical cluster analysis (HCL). The average composition values showed a substantial variation among wheat varieties due to different wheat varieties. Wheat cv. Shinmichal1 (waxy wheat) had the highest ash, lipid, and total dietary fiber contents of 1.76, 3.14, and 15.49 g/100 g, respectively. Using HCL efficiently classified wheat cultivars into 7 clusters. Namhae, Sukang, Gobun, and Joeun contained higher protein values (12.88%) and dietary fiber (13.74 %). Regarding multi-trait crop breeding, the variation in chemical compositions found between the clusters might be attributed to wheat genotypes, which was an important factor in accumulating those chemicals in wheat grains. Thus, once wheat cultivars with agronomic characteristics were identified, those properties might be included in the breeding process to develop a new variety of wheat with the trait.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.516-521
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• 2018

"Nulichal" was developed by the National Institute of Crop Science, RDA, in 2010. The initial cross was conducted in 2000, and an elite line (HB15305-B-B-31-2) was selected in 2005. Subsequently, preliminary yield and advanced yield trials have designated it as "Iksan 95." It showed good agronomic performance in regional yield trials from 2008 to 2010 and was released as "Nulichal," with resistance against the barley yellow mosaic virus (BaYMV) and high yields with a waxy endosperm. The average heading and maturation dates of "Nulichal" were April 24 and May 30, respectively in paddy fields, which were 1 day later than those of the check cultivar "Saechalssalbori." It had culm and spike lengths of 82 and 4.0 cm, respectively. It showed $774spikes/m^2$, 63 grains/spike, 25.0 g of 1,000-grain weight, and 793 g of test weight. "Nulichal" showed higher levels of resistance to BaYMV than the naturally occurring Iksan (type III strain), Naju (type I), and Jinju (type II). The expansion rate was higher than that of "Saechalssalbori" and its hardness, gumminess, and chewiness were lower than those of "Saechalssalbori." Its average pearled grain yield in the regional yield trial was 4.00 MT/ha in paddy fields, which was 10% higher than that of the check cultivar. The combined availability of "Nulichal" was improved by its increased culm length compared with that of "Hinchalssal."

• Journal of Crop Science and Biotechnology
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• v.11 no.3
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• pp.181-186
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• 2008

To assess the potential as biofortified rice varieties, new endosperm and grain mutant lines were selected from $M_4$ generation seeds of the rice cultivar Shindongjin, which were either $\gamma$-irradiated or treated with N-methyl-N-nitrosourea(MNU) and lipid, sugar, and tocopherol content were analyzed. Amylose content in non-waxy mutants ranged from 8.8% in SM-4, a dull-type mutant, to 29.5% in SM-51, compared to 18.9% in the parental variety, Shindongjin. SM-23, a floury-type mutant, contained 0.09 ${\mu}g/g$ $\alpha$-tocopherol(40.9% of total tocopherol), was three times higher than in the parental variety. SM-32, a giant embryo-type mutant, had a 2.2-fold higher total tocopherol content, 2.1-fold higher $\alpha$-tocopherol, and 5.5-fold higher $\delta$-tocopherol content(47.3% of total tocopherol) than the parental variety(0.13 ${\mu}g/g$). Total free sugar content was elevated in all selected mutants and 1.2-8.6 times higher than in the parental variety(11.38 ${\mu}g/g$). These increased sugar levels were due to increase in sucrose concentration. SM-23(floury-type mutant) and SM-51(high amylose-type mutant) had 4.6 and 7.0 times more sugar, respectively, than the parental variety(11.38 ${\mu}g/g$). With relatively high concentrations, most mutants showed elevated fatty acid content in the SM 32(giant embryo-type) and SM-51(high amylose-type) mutants, at 124.56 and 89.59 mg/g, respectively. All selected mutants displayed valuable characteristics for the development of new varieties in rice-breeding programs.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.515-524
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• 2010

The amylose content of starch is a major factor in the texture of cooked cereal grains. Therefore, down-regulation of amylose synthesis is one of the alternative method to improve eating quality of rice. We developed transgenic rice plants designed to suppress granule-bound starch synthase I(GBSSI) gene using RNA interference(RNAi) technology. Transgenic plants with RNAi vector containing the 3'-UTR region of GBSSI showed a lower amylose content in rice endosperm than that of wild-type. The range of amylose content was 5.9~9.0% in the transgenic plants, whereas that of wild-type was 17.7~18.0%. Transgenic rices showed the decrease of short chain and the increase of long chain by analyzing chain length distribution of amylopectin in the endosperm. In the SEM micrographs, we found that compound starch granules in whole grains of the wild-type rice were readily split during fracturing, while the starch granules in RNAi-transgenic lines showed small voluminous, non-angular rounded bodies.

• Applied Biological Chemistry
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• v.46 no.2
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• pp.117-122
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• 2003

Starches from 4 rice cultivars, including Whachungchalbyeo and Whachungbyeo, together with two correspondiug conversion mutants with giant embryonic phenotype, Whachungchal-giant embryonic rice and Whachung-giant embryonic rice, were isolated to compare its physico-chemical properties. The amylose content and the length of glucose chains in the fractionated amylose was reduced in response to conversion of the rice cultivars for developing giant embryonic phenotype. For the fine structure of amylopectin, conversion to giant embyonic rice cultivars accompanied with slight increase in the length of B chain plus decrease in the amount of A chain, and also a slight increase in average glucose chains length of amylopectin fractions could be observed. X-ray diffractogram revealed 4 cultivars to be the representative A types. We could also obtain the results that the hydrolysis rate by glucoamylase in the waxy rice cultivars decreased in response to conversion to the giant embryonic rice cultivars, while the rate increased in the non-waxy rice cultivas. Termination temperature for gelatinization was observed to decrease in response to conversion into the giant embryonic rice cultivars, however, the enthalpy for gelatinization was found to increase with the same conversion process.

• Plant Resources
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• v.4 no.3
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• pp.140-146
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• 2001

This study was conducted to investigate the $\beta$-glucan contents and their characteristics of winter cereals according to particle sizes and milling recoveries. Sieved fractions differed in their average contents of $\beta$-glucans, and the coarse fraction had higher contents of $\beta$-glucan than finely milled fractions. In all winter cereals, the $\beta$-glucan contents of raw flours were higher than those of their brans, and the highest $\beta$-glucan contents of every cereals were observed at 100 mesh > or 100-140 mesh fractions except the Chalssalbori fractions which showed the higest $\beta$-glucan contents (12.9%) at 140-200 mesh fraction. As compared with the $\beta$-glucan content of Chalbori among the various milling recoveries, the $\beta$-glucan was distributed more evenly throughout the endosperm but $\beta$-glucan content in bran of Chalbori was only 1.5%. However, $\beta$-glucan content of Chalssalbori (hull-less waxy barley) was the highest in the subaleurone region (8.2%) and declined slightly toward inner layers of grain. This results suggest that $\beta$-glucan distribution between high (Chalbori) and low $\beta$-glucan barley (Chalssalbori) may explain the difference in milling performance of barley. On the other hand, $\beta$-glucan contents of two rye varieties (Chilbohomil, Chunchoohomil) were lower than those of two waxy barley varieties, and the higest $\beta$-glucan contents were observed at the 60% milling recoveries. In all winter cereals, the L-values (lightness) of raw flours were higher than those of brans. And the L-values of barley varieties were higher than those of oat and rye varieties. As the particle sizes and milling recovery ratios were decreased, the L-value were increased. The a-values (redness) in brans of every winter cereals were higher than those of every particle size flours and every milling ratio fractions, and this tendency was observed in the b-values (yellowness) of every particle size of cereal flours. The L and b-value of barley, the b-value of oat, and L, a, b-value of rye have the significant relationship with the $\beta$-glucan contents, respectively. This results represent the fact that $\beta$-glucans affected the color of the flours and pounded grains of winter cereals.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.335-339
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• 2006

The level of ${\beta}-glucan$ which is a major soluble dietary fiber found in the grain endosperm cell wall was highly variable among 25 barley genotypes grown at four locations including Suwon, Naju, Jinju, and Jeju. Statistically significant genotypic effects were observed for ${\beta}-glucan$ content at each or across growing sites (P<0.001). On average, 'Chalssalbori' showed the lowest percentage ${\beta}-glucan$ (4.04%) among genotypes in the grain, whereas 'Yonezawa Mochi' was highest in percentage ${\beta}-glucan$ (6.46%) compared to other genotypes. The significant difference between genotypes was approximately 1-2% across environments. The effects of location or interaction between locations and genotypes were not significant on the variation of ${\beta}-glucan$ contents. High ${\beta}-glucan$ content seemed to be greatly associated with such grain traits as waxiness and presence of husk except for 'Chalssalbori'. The waxy genotypes had a mean of 5.37% and values ranging from 5.28 to 5.47%, but normal genotypes had a mean of 4.78% and values ranging from 4.69 to 4.88% over environments. Hulless barley genotypes were also higher than hulled barley genotypes for the average ${\beta}-glucan$ content in both individual and over all environments. The difference between the hulled and hulless gene pools was on average of 0.37% with ranges from 0.19% to 0.56% at four environments. ${\beta}-glucan$ content measured from a mapping population of $F_5$-derived 107 lines derived from the cross between 'Yonezawa Mochi' and 'Neulssalbori' was not significantly associated with other agronomic traits except for 1,000-kernel weight at the '01 Suwon environment. Not too much information on the relationship of ${\beta}-glucan$ content to agronomic traits was available.

• Korean Journal of Breeding Science
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• v.41 no.2
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• pp.92-100
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• 2009

To investigate the mutagenecity of sodium azide (SA) and to select mutants having various agronomic characteristics in rice (Oryza sativa L. ssp. japonica), dry seeds of rice variety 'Suweon 472' were treated with 0, 0.5, 1.0, 2.0, and 4.0 mM SA solutions prepared in 0.1 M phosphate buffer (pH 3.0). Germination rate, seedling height and sterility were investigated in $M_1$ generation and chlorophyll mutations were observed in $M_3$ generation. Germination rate and seedling height decreased as the increase of SA concentration in $M_1$ generation, the maximum seed sterility (40.8%) was found at 4.0 mM SA concentration. Chlorophyll mutants were occurred in $M_3$ generation and the frequency calculated on a line basis was 13.5% at the same treatment. Many kinds of mutations for morphological and agronomic characters were observed and mutations with short culm and glabrous leaf were frequently found in $M_3$ generation. Interestingly, five mutant lines resistant to blast or bacterial blight (BB) were selected and evaluated with several isolates in $M_3$ generation although Suweon 472 has been known to be susceptible to blast and BB. These mutants showed all resistance to seven isolates of blast and a total of 76 lines among 2,567 lines evaluated showed resistant to race K1 of bacterial blight. Two mutant lines (440172 and 41272) showed different reaction to BB isolates from the other resistant mutants. A few kinds of endosperm mutants were also identified and most of them were waxy mutants.