• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.6
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• pp.489-494
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• 1993

The amount of maize being imported from other countries to meet the national demand are increasing every year. Regardless of the usage whether it is for silage or for human consumption, amount of seeds for farmers are ever being increased. In order to solve the problems arising from the seed import, a program for developing waxy hybrids with high quality was set up at the College of Agr., Chungnam National University. The main breeding targets for high quality waxy hybrids are focused on the pericarp thickness. In order to obtain basic information needed for developing hybrids with thin pericarp, six inbred lines all derived from open pollinated Korean waxy lines were diallel crossed. Results obtained indicate that waxy hybrids with thin pericarp can be developed by choosing proper parental lines. Of the six inbreds, Jewon inbred had utmost thin pericarp compared with other lines. Hybrids crossed with Jewon showed also thinner pericarp than other hybrids. However, Danyang which has thick pericarp showed thicker pericarp in hybrid combinations. Variance due to general combining abilities was greater than the variance due to the specific combining abilities, indicating that additive gene effects are more important. The pericarp thickness of waxy hybrid endosperm varied with the parts of pericarp. The germinal side of the pericarp is comparatively thinner than the abgerminal side. The upper part (crown) has thicker pericaip than lower part (tip) of the kernel.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.430-441
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• 2011

Maize is divided into two types based on the starch composition of the endosperm in the seed, normal maize(or non-waxy maize) and waxy maize. In this study, genetic diversity and population structure were investigated among 80 waxy maize and normal inbred lines(40 waxy maize inbred lines and 40 normal maize inbred lines) using 50 SSR markers. A total of 242 alleles were identified at all the loci with an average of 4.84 and a range between 2 and 9 alleles per locus. The gene diversity values varied from 0.420 to 0.854 with an average of 0.654. The PIC values varied from 0.332 to 0.838 with an average of 0.602. To evaluate the population structure, STRUCTURE 2.2 program was employed to confirm genetic structure. The 80 waxy and normal maize inbred lines were separated with based on the membership probability threshold 0.8, and divided into groups I, II and admixed group. The 13 waxy maize inbred lines were assigned to group I. The 45 maize inbred lines including 7 waxy maize inbred lines and 38 normal maize inbred lines were assigned to group II. The 22 maize inbred lines with 20 waxy maize inbred lines and 2 normal maize inbred lines were contained in the admixed group. The cluster tree generated using the described SSR markers recognized three major groups at 31.7% genetic similarity. Group I included 40 waxy maize inbred lines and 11 normal maize inbred lines, and Group II included 27 normal maize inbred lines. Group III consist of only 2 normal maize inbred lines. The present study has demonstrated the utility of SSR analysis for the study of genetic diversity and the population structure among waxy and normal maize inbred lines. The information obtained from the present studies would be very useful for designing efficient maize breeding programs in Maize Experiment Station, Kangwon Agricultural Research and Extension Services.

• 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.

• Proceedings of the Korean Society of Crop Science Conference
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• 2007.11a
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• pp.221.2-221.2
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• 2007

• KOREAN JOURNAL OF CROP SCIENCE
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• v.67 no.4
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• pp.265-273
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• 2022

Waxy corn (Zea mays L.), which contains homozygous mutant alleles for the waxy1 (wx1) gene, is widely consumed as a snack food in Asia. This study evaluated sixteen agronomic characteristics of inbred Korean waxy corn lines to aid development of high-quality waxy corn cultivars. The plant materials studied were 177 inbred waxy corn lines developed by the National Institute of Crop Science, Rural Development Administration, Republic of Korea. For the tested lines, days to tasseling and silking averaged 77.69±2.22 days (with a range of 56-97 days), and 81.12±7.56 days (66-99 days), respectively. Plant length ranged from 88 to 237 cm (averaged 164.88±22.67 cm), ear length averaged 11.75±2.52 cm (5.0-18.5 cm), and ear width averaged 2.94±0.68 cm (1.4-4.5 cm). The number of rows on each ear of corn averaged 12.22±2.22 (7-32 rows) and the kernel number averaged 24.30±4.22 (9-37 kernels) per row. The crude protein content was 12.05±1.53% (8.90-21.80%) and total starch content was 69.27±5.74% (49.5-83.9%). Principal component analysis revealed that ear width, grain length, ear length, days to tasseling, days to silking, percentage of ear setting height, and total starch are features that allow distinction between the 177 waxy inbred corn lines. Hierarchical cluster analysis identified twelve waxy inbred lines that produce tall plants and have a short silking period. These lines may improve yield among quickly growing corn varieties.

• Korean Journal of Breeding Science
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• v.42 no.1
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• pp.1-10
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• 2010

Five mutants were investigated at the molecular level to determine the factors responsible for mutated endosperm types. They were classified as high (HA) or low amylose (LA) phenotypes based on the amylose content in endosperm. The five were previously produced from Ilpum and Shindongjin cultivar treated with N-methyl-N-nitrosourea and gamma-ray irradiation, respectively. Analysis of the genomic structure and expression of Granule-bounded Starch Synthase I (GBSSI) genes revealed that mutants generally showed a higher incidence of nucleotide transition than transversion, and the $A:T{\rightarrow}G:C$ transition was particularly prevalent. The rates of nucleotide substitution in HA mutants were generally higher than those in the LA mutants, leading to higher substitutions of amino acid in the HA mutants. Neither nucleotide substitutions interfering with intron splicing or causing early termination of protein translation were found, nor any large-sized deletions or additions were found in all the mutants. In principle, amylose content can be regulated by three factors: internal alterations of GBSSI protein, the strength of gene expression, and other unknown external factors. Our results indicate that the endosperm mutants from Shindongjin arose from internal alterations of GBSSI proteins, which may be the result of amino acid substitutions. On the other hand, the Ilpum mutants might be principally caused by the alteration of gene expression level. Analysis of another three glutinous cultivars revealed that the major factor leading to glutinous phenotypes is the 23-bp duplicative motif (5'-ACGGGTTCCAGGGCCTCAAGCCC-3') commonly found in exon 2, which results in the premature termination of protein translation leading to the production of a non-functional GBSSI enzyme.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.3
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• pp.197-203
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• 1991

Several types of endosperm and embryo mutants were induced by the treatment of MNU (N -methly- N -nitrosourea) on fertilized egg cell of rice plant. These mutants were named as dull. waxy, white core, floury, sugary, shrunken, colored seed coat and giant embryo according to their appearence, micro-scopic feature on SEM and amylose content. White cored mutant was the most frequent one among them. All of the mutants were segregated as controlled by a single recessive gene except 47320 (dull). Futher studies on the genetics and physico-chemical properities of the mutants are ongoing.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.375-382
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• 2011

A chemical, MNU-induced hulless barley mutant line designated as 'Mutant 98 (M98)' was developed from a Korean hulless waxy barley cultivar, 'Chalssalbori'. The objective of the study was to determine the genetic basis of 'M98' and the possibility of using 'M98' as breeding parent to improve lysine level. Compared to 'Chalssalbori', 'M98' had large embryo and higher lysine content in both the embryo and endosperm. Significantly different lysine content in 'M98' and the other high-lysine barley mutant stocks was observed for two years. However, the genotype by year interaction was not significant. 'M98' was higher than the other high-lysine barley mutant stocks in the percentage of lysine of total amino acid composition (0.75%). The trait of shrunken endosperm of 'M98', which was typical in the high-lysine mutants, was inherited by a single recessive gene. Based on seed morphology and lysine content of $F_1$ seeds, 'M98' had a genetically different gene from the other high-lysine mutants for shrunken endosperm. Segregation of $F_2$ for plump/shrunken endosperm did not fit the expected ratio of Mendelian inheritance except for only one cross combination (GSHO1784 (lys1)/M98). The amino acid analysis of $F_5$ and $F_6$ progenies from the cross between 'M98' and 'Chalssalbori' revealed that the attempt to increase the range of lysine content of plump lines did not go beyond the limit of the average high-lysine barley germplasm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.5 no.1
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• pp.57-64
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• 1969

Several field and sweet corn varietiea from several sources were crossed with a variety carrying the opaque-2 gene to determine the phenotypic interactions in the breeding of high lysine maize. Although opaque-2 lines showed lower protein content than the corresponding normal varieties, there was no correlation between the protein levels of the two types. opaque-2 maize contained more lysine, but no relationship was found between the protein content and the lysine content of either normal or opaque-2 types, suggesting that high lysine corn using the opaque-2 gene may be developed independently from the protein content. The F2 segregation ratios for normal and opaque-2, 100-kernel weights, percentage seed set, opaque-2 phenotype, disease susceptibility, and the relationship between protein and lysine content of normal and opaque-2 were investigated. The determinations and observations were made on the F2, F3, and BC1 Lysine content was determined by the ion exchangeresin combined with paper chromatography method. Most crosses segregated in a 1-opaque-2 : 3-normal ratio as expected. Opaque-2 segregates were lighter than the normal type and smaller in size. A mottled phenotype of opaque-2 maize observed in the Philippines yellow endersperm. In some varieties opaque-2 maize was very susceptible to the ear and kernel rot disease. No. 5(female) and opaque-2(male). Selectlon of a double mutant of waxy and opaque-2 by using the iodine technique and electric lamp was discussed. opaque-2 and floruy-2 were not allels. Different percentage of seed set were observed in the segregation of aewx crossed with opaque-2. An unusual gametophytie relationship was involved in a cross between Glutinous.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.181-191
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• 2009

To investigate the genetic variation of high-and low-molecular-weight glutenin subunits (BMW-GS and LMW-GS), granule-bound starch synthase I (GBSSI) and puroindoline in 24 Korean wheat cultivars. At the BMW-GS compositions, three Glu-A1 alleles, five Glu-B1 alleles and three Glu-D1 alleles were identified. The high frequency of alleles at each locus was Glu-A1c allele (15 cultivars), Glu-B1b allele (16 cultivars) and Glu-D1f allele (16 cultivars). Four alleles were identified at the Glu-A3 and Glu-B3 loci and three at Glu-D3 locus and Glu-A3d, Glu-B3d and Glu-D3a were mainly found at each Glu-3 locus. Glu-A3d, Glu-B3d, Glu-D3b or c (4 cultivars, respectively) and Glu-A3d, Glu-B3d, Glu-D3a and Glu-A3c, Glu-B3d or h, Glu-D3a (3 cultivar, respectively) were predominantly found in Korean wheats. At the GBSS compositions, 2 waxy wheat cultivars, Shinmichal and Shinmichal1, showed null alleles on the Wx loci and other cultivars were wild type in GBSS compositions. At the puroindoline gene compositions, Korean wheat cultivars carried 3 genotypes, which 10 cultivars (41.7%) were Pina-D1a and Pinb-D1a, 11 cultivars (45.8%) had Pina-D1a and Pinb-D1b and 3 cultivars (12.5%) carried Pina-D1b and Pinb-D1a. These genetic variations could present the information to improve flour and end-use quality in Korean wheat breeding programs.