The composition of high-molecular-weight-glutenin subunits (HMW-GS) is a key determinant of wheat baking properties. These subunits are encoded by the GLU-A1, GLU-B1, and GLU-D1 loci on the long arm of chromosome 1 and consist of x- and y-type subunits. Allelic variations in composition are a major factor influencing bakery quality. Unlike sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) or ultra-performance liquid chromatography (UPLC), which often fail to resolve closely related allelic variants, PCR-based markers allow for clear and definitive discrimination at the DNA level. Building on the results of a previous study that determined the GLU-B1 allele composition, we aimed to confirm—through the use of PCR markers—the allele compositions of GLU-A1 and GLU-D1 in 44 domestic wheat varieties. The results showed that “Jonong” and “Sinmichal1” contained the Glu-A1b (A1x2*) allele rather than Glu-A1a (A1x1) or Glu-A1c (A1x-null). Additionally, “Jonong” and “Sinmichal1” exhibited the allelic composition Glu-D1a (D1x2+D1y12), rather than Glu-D1d (D1x5+D1y10) or Glu-D1f (D1x2.2+D1y12). These results were compared with those obtained by SDS-PAGE and UPLC. The PCR-based markers used to identify GLU-A1 and GLU-D1 alleles in this study will be valuable for determining the allelic composition at the GLU-A1 and GLU-D1 loci in domestic wheat varieties. Furthermore, the re-evaluated genetic composition is expected to improve the precision of assessments related to the baking quality of domestic wheat.

Improving nitrogen use efficiency (NUE) is essential for sustainable wheat production, given the global demand for high-yielding and environmentally resilient crop varieties. NUE is a complex trait governed by multiple genetic, physiological, and environmental factors. This review synthesizes recent advances in the genetic dissection of NUE in wheat, focusing on quantitative trait loci (QTL) mapping, genome-wide association studies (GWAS), and transcriptome analyses. Furthermore, novel approaches such as protein turnover quantification, epigenetic regulation, NIR-based quality prediction, and genomic selection optimization are discussed as emerging strategies to enhance NUE. Key genes identified include nitrate transporters (NRT1, NRT2), nitrogen assimilation enzymes (GS, GOGAT), transcription factors (NLPs, WRKYs, NACs), and signal transduction components (SnRK, CIPK). Integrative studies combining genomics, transcriptomics, and machine learning offer new insights into the dynamic regulation of NUE. This review highlights the importance of multi-layered breeding approaches and provides valuable genetic resources and methodological frameworks for future wheat NUE improvement programs.

A comprehensive evaluation of 515 Korean wheat germplasms, including cultivars, experimental lines, and landraces, was conducted over 2 years under upland field conditions to characterize major agronomic and grain traits. Allelic variation at 13 key functional loci was assessed using Kompetitive Allele-Specific PCR (KASP) and PCR-based markers. The winter-type vrn-A1 with a single copy (CNV=1; 40.2%) advanced heading by approximately 5 days compared to multiple-copy genotypes, and winter-type vrn-B1 (88.5%) advanced heading by 2 days compared to the spring-type. The photoperiod-insensitive alleles Ppd-B1a (5.6%) and Ppd-D1a (76.3%) advanced heading by 3 and 4 days, respectively, with a combined effect of up to 6 days. Semi-dwarfing alleles Rht-B1b and Rht-D1b showed reduced culm lengths of 2.1 cm and 4.7 cm, respectively, and the Rht-B1a/Rht-D1b genotype was 6 cm shorter than Rht-B1a/Rht-D1a. The Pina-D1a/Pinb-D1a genotype had the lowest kernel hardness value (32.2), whereas Pina-D1b/Pinb-D1a had the highest (60.5). The thousand kernel weight ranged from 36.1 mg to 42.5 mg depending on the allelic combinations of TaCwi-A1, TaGW2-6A, and TaSus2-2B. Cultivars and experimental lines were clearly distinguished from landraces based on phenotype-based clustering, with the majority of cultivars (81.6%) and experimental lines (68.3%) grouped into cluster III. In contrast, landraces were predominantly distributed in clusters I (55.1%) and II (29.2%). Random forest analysis identified four genes, Ppd-D1, Pina-D1, Pinb-D1, and WAPO-A1, as major contributors to cluster classification. Cluster III was highly enriched with alleles favorable for earliness (Ppd-D1a, 98.3%) and grain hardness (Pina-D1b and Pinb-D1b, 57.9%). WAPO-A1b, an allele associated with an increased spikelet number per spike, was more frequently observed in clusters I (94.6%) and II (79.1%) than in cluster III (58.4%).

Wheat is a fundamental staple crop worldwide, contributing significantly to global food security due to its versatility and nutritional value. However, gluten proteins, including gliadins and glutenins, have been implicated in various health problems, such as celiac disease, non-celiac gluten sensitivity, and wheat allergies. These disorders affect a wide variety of people globally, creating demand for wheat varieties that balance high-end-use quality with reduced immunogenic potential. This review examines the molecular and genetic mechanisms that regulate gluten protein synthesis, highlighting recent advances in genomic and mutagenic approaches aimed at modifying gluten proteins to enhance the health and quality traits of wheat. Technologies such as RNAi and CRISPR/Cas9 offer promising avenues for reducing wheat immunogenicity without compromising its functional properties in food production. This study also examines the challenges and prospects of utilizing these genetic tools to develop wheat varieties that achieve the dual
objective
s of enhanced health outcomes and high product quality.

Salt stress is a major abiotic factor that limits wheat production worldwide. However, this threat is increasing significantly because soil salinity affects approximately 20% of the irrigated agricultural land globally, leading to significant yield losses by impairing plant growth and photosynthetic efficiency. This study aimed to identify single-nucleotide polymorphisms (SNPs) associated with salt tolerance in wheat core collections during the heading stage under saline stress conditions. Chlorophyll content, a physiological indicator of salt tolerance at heading, and soil electrical conductivity (EC) were measured in 609 accessions and a Salt Tolerance Index (STI) was subsequently constructed. Genome-wide association studies (GWAS) were performed using a 35 K SNP chip to identify significant marker-trait associations. Three models (MLM, FarmCPU, and BLINK) were employed for the GWAS, with FarmCPU and BLINK demonstrating superior power over the MLM in controlling false positives. GWAS results revealed four significant SNPs (AX-94929101, AX- 94615611, AX-94510535, and AX-94411611) located on chromosomes 3D, 5D, and 7D. AX-94510535 exhibited significant phenotypic differences based on SNP genotype, suggesting its potential as a marker for STI. Furthermore, the identified candidate genes, TraesCS3D02G218100, TraesCS5D02G059500, and TraesCS5D02G175000, were implicated in biological processes such as DNA replication, cell death, and photosynthesis.

Wheat (Triticum aestivum L.) is a major cereal crop grown worldwide, providing approximately 20% calorie and 25% protein intake. Wheat productivity is significantly affected by high temperatures, particularly during the grain-filling period. Heat stress accelerates leaf senescence, impairs photosynthesis, reduces starch accumulation, and alters protein synthesis, ultimately leading to a decrease in grain yield and quality. To mitigate the adverse effects of heat stress, wheat utilizes adaptation mechanisms, including the expression of heat shock proteins, activation of antioxidant defense systems, osmotic regulation, and transcription factor-mediated gene regulation. Stay-green traits also play a role in maintaining photosynthetic efficiency at high temperatures. Breeding strategies such as traditional breeding, marker-assisted selection , genomic selection , and genome editing are being explored to improve heat tolerance. Recent advances in the CRISPR-Cas9 technology enable precise gene editing, thereby enhancing the resilience of wheat to heat stress. Additionally, quantitative trait locus mapping and genome-wide association studies facilitated the identification of genetic regions associated with heat tolerance, thereby accelerating the development of climate-resilient wheat varieties. Future research should focus on integrating genetic and molecular approaches with sustainable agronomic practices and crop modeling strategies to optimize wheat productivity under rising temperatures. The integration of advanced breeding techniques and improved crop management can facilitate the development of wheat varieties that are more resilient to climate change.

Wheat, in conjunction with rice and maize, constitutes one of the three most significant staple crops worldwide, sustaining over 40% of the global population. In Korea, the annual per capita wheat consumption exceeds 30 kg, totaling approximately 4 million tons nationwide. However, more than 95% of this demand is met through imports, resulting in a meager self-sufficiency rate of approximately 0.7%, raising concerns regarding supply stability and price fluctuations. Enhancing wheat self-sufficiency in Korea requires addressing yield reductions caused by abiotic stressors, including elevated temperatures, drought, cold damage and pre-harvest sprouting induced by climate change, as well as biotic stressors such as Fusarium head blight. The development of high-quality wheat varieties with superior processing characteristics that satisfy consumer demands is crucial. This study provides critical insights for future research on the development of novel wheat cultivars in Korea. It reviews the current state of wheat cultivation and production, environmental and biological factors affecting growth, compositional elements influencing quality, domestic cultivars developed through conventional crossbreeding currently in commercial distribution, and contemporary breeding trends, with particular emphasis on novel breeding technologies, such as biotechnology.

A new winter wheat (Triticum aestivum L.) cultivar “Joongmo2015” was developed by the NICS (National Institute of Crop Science), RDA (Rural Development Administration) in 2019. Its heading date was April 20 and its maturity date was June 1, which was similar to Keumkang. “Joongmo2015” had a longer culm length (80 cm), similar spike length (7.8 cm) and spikes per m² (804), lower 1,000-grain weight (43.0 g) than “Keumkang” (78 cm, 7.8 cm, 804 g, 46.3 g, respectively). “Joongmo2015” was showed stronger to winter hardiness than “Keumkang”, and susceptible to fusarium head blight and powdery mildew. The average grain yield in the advanced yield trial (AYT) was 4.97 MT/ha, which were 26% more than “Keumkang” and in the regional yield trial (RYT) was 5.75 MT/ha in upland and 5.27 MT/ha in paddy field, which were 16% and 18% higher than those of “Keumkang” (4.95 MT/ha and 4.46 MT/ha, respectively). “Joongmo2015” showed lower protein content (11.7%), SDS-sedimentation volume (42.8 ml), gluten content (9.0%) and flour lightness(90.76) than “Keumkang” (13.6%, 61.8 ml, 11.4% and 91.50, respectively). “Joongmo2015” showed higher lightness (83.10) of noodle dough sheet than “Keumkang” (82.48). “Joongmo2015” exhibited higher hardness (3.92N) and similar springiness and cohesiveness of cooked noodles (0.94 and 0.60) compared to “Keumkang” (3.65N, 0.93, and 0.59, respectively). High molecular weight gluten subunits (HMW-GS) composition are Glu-D1d (5+10), granule-bound starch synthase (GBSS) composition are Wx-A1a, Wx-B1a, Wx-D1a and composition of puroindolines are Pina-D1a, Pinb-D1a (Registration No. 9790).

Breeding wheat cultivars with high nitrogen use efficiency is crucial for sustainable agriculture. In this study, 130 durum wheat accessions from 53 countries were cultivated under two nitrogen fertilization levels to investigate variations in agronomic traits and identify accessions suitable for low-nitrogen conditions. Under no nitrogen fertilization, SPAD value (-99.2), flag leaf length (−15.8 mm), grain area (−0.52 mm²), grain length (−0.27 mm), thousand-grain weight (+5.2 g), and grain protein content (−4.2%) showed significant differences compared to that under standard nitrogen fertilization. Among these traits, the SPAD value exhibited a strong positive correlation with protein content in the absence of nitrogen fertilization, suggesting its potential as an indicator for selecting germplasm with superior nitrogen use efficiency. Hierarchical cluster analysis, based on the differences in the six traits under the two nitrogen fertilization levels, classified the 130 durum wheat accessions into three groups (Groups 1, 2, and 3). Accessions in Group 2 exhibited superior adaptability under no nitrogen fertilization compared with those in the other two groups. We identified seven accessions in Group 2 that exhibited minimal decreases in SPAD values and protein content under no nitrogen fertilization for use in wheat breeding programs aimed at developing cultivars with high nitrogen use efficiencies.

In common wheat (Triticum aestivum L.), the protein content and glutenin protein composition are the key quality-determining parameters. Allelic variations, especially in high-molecular-weight glutenin subunits (HMW-GSs), affect bread quality significantly. The HMW-GS Glu-1 locus consists of two tightly linked genes encoding x- and y-type subunits that exhibit highly variable frequencies. In this study, we evaluated Glu-B1 alleles using allele-specific PCR markers in 44 domestic wheat cultivars. The composition of Glu-1Bx7+Glu-1By8 in the 24 cultivars was either Glu-1Bx7+Glu-1By8, Glu-1Bx7*+ Glu-1By8, or Glu-1Bx7*+Glu-1Bx8*. In addition, the two cultivars initially identified Glu- 1Bx7+Glu-1By8* were corrected to Glu-1Bx7*+Glu-1By8*. Seven cultivars previously classified as having Glu-1Bx7+Glu-1By9 composition contained Glu-1Bx7*+ Glu-1Bx9. The allele composition of the cultivar was identified as Glu-1Bx20+Glu-1By20 instead of Glu-1By20. The HMW-GSs of 21 wheat varieties were analyzed using ultra-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These results will be helpful for evaluating the composition of Glu-B1 alleles in domestic wheat and accurately assessing the quality of domestic wheat flour.

Fusarium head blight (FHB) causes yield reduction, quality deterioration, and mycotoxin contamination in wheat, highlighting the need for resistant wheat varieties. In this study, we evaluated FHB resistance genes and infection rates in 44 domestic wheat varieties. Among them, 42 had the Type I resistance gene Fhb4, 37 had Fhb5, and 35 possessed both. For Type II resistance, 14 had Fhb1, 11 had Fhb2, and five had both. Twenty cultivars had both type I and type II resistance genes, and among them, Chungkye, Dahong, Gobun, Namhae, and Ol had all of the Fhb1, Fhb2, Fhb4, and Fhb5 genes. The average infection rate over three years was 42.6% in cases with both Type I and Type II resistance genes and 44.3% in cases without Type II resistance genes. The infection rate was very high in 2020 and very low in 2021, complicating the analysis of the three-year average. However, when the infection rate was evenly distributed in 2019, there was a tendency for increased resistance among the varieties carrying Type II resistance genes. This suggested that external factors may influence infection rates, emphasizing the need for a precise evaluation system suitable for selecting additional resistance genes. In addition, it is necessary to develop resistant varieties suited to the domestic environment through additional resistance gene selection and integration of resistance genes. This study contributes to understanding FHB resistance genes in domestic wheat varieties and developing resistant domestic wheat varieties.

To stably produce domestic wheat under water-scarce environmental conditions due to climate change, root characteristics with excellent water utilization rates are crucial. In this study, we analyzed the root and grain phenotypes of 37 domestic wheat varieties over a two-year period by combining the results of genetic mutations related to semi-dwarfing and grain size. Root length was positively correlated with maximum root depth (r=0.76**) and total seminal root length (r=0.54**), whereas it was negatively correlated with the number of roots (r=-0.33**) and root angles (r=-0.51**). The thousand-kernel weight was positively correlated with embryo width (r=0.34**) and embryo area (r=0.33**) but was not correlated with other root traits. Embryo length was positively correlated with the number of roots (r=0.34**) and coleoptile length (r=0.42**). Phenotypic analyses of roots and grains, along with genotypic analyses of semi-dwarfing (Rht-B1 and Rht-D1) and grain size (TaCWI-4A, TaCWI-5D, TaGW2-6A, TaSus2-2B) genes, revealed that the Rht-D1b genotype led to reduced root depth, increased root angles, and reduced coleoptile length. TaCwi-A1, TaCWI-5D, TaSus2-2B, and TaGW2-6A, possessing the alleles TaCwi-A1a, Hap-5D-C, Hap-L, and Hap-6A-G associated with a larger grain size, resulted in an increased number of roots and root depth. Domestic wheat varieties were categorized into three clusters based on root, grain, and coleoptile trait characteristics, with 15 varieties in Cluster I, 9 in Cluster II, and 13 in Cluster III. The results of this study can be utilized in basic research to develop varieties that can produce stable domestic wheat by selecting resources with excellent root growth and seed characteristics.

Preserving and utilizing genetic diversity is crucial in crop breeding to address unpredictable situations such as climate change and evolving consumer demands. It serves as a source of new traits and alleles. Core collections are established from approximately 10-20% of conserved resources, and they are not only used for efficient management of genetic resources in seed banks but also applied in crop improvement programs and new gene discovery. These core collections demonstrate diversity based on the geographic origin of genetic resources and provide information on genetic similarity among resource types and collection regions. Recent advances in high-throughput genotyping has enabled high-resolution association mapping, allowing for the precise discovery of new genes and QTLs. The wheat genetic diversity and population structure of core collections are important in determining appropriate GWAS statistical methods for detecting these novel genes and QTLs. To maximize their utility, collecting detailed phenotypic data is crucial. This will expand their application in gene discovery, marker development, and more. In this study, we provided reviews for wheat core collection in the world to face the digital breeding era, where precise gene detection and manipulation are possible. The accumulation of genetic diversity, and phenotypic and genotypic information by core collections will contribute to breeding cycle acceleration and trait selection optimization.

Since iron (Fe) and zinc (Zn) are essential micronutrients for human immunity and metabolic activities, it is important to biofortify major food crops such as wheat and improve the bioavailability of Fe and Zn. In this review, we focused on analyzing studies conducted to identify and evaluate QTLs, genes, and associated molecular markers related to Fe and Zn content in wheat, their absorption mechanisms, and bioavailability in terms of genetics and breeding. Because bread wheat has a limited Fe and Zn content in its grains, many studies have used wild, synthetic, or mutant wheat resources with high Fe and Zn contents. Many studies have been conducted to characterize related genes, of which Gpc-B1 is the major gene that increases the final content of Fe, Zn, and protein in association with an Gpc-B1 increase in Fe uptake and regulate Zip and YSL expression. Research determining the appropriate phytic acid content and increasing phytase activity to improve bioavailability was also highlighted.

A new winter wheat (Triticum aestivum L.) cultivar “Hwanggeumal” was developed by the National Institute of Crop Science (NICS) Rular Development Administration (RDA) in 2019. Its heading date was April 20, and its maturity date was June 1, which was similar to that of Jokyung. “Hwanggeumal” had a shorter culm length (75 cm) and spike length (7.1 cm). However, it had lower spikes per m² (699) and 1,000-grain weight (44.2 g) than “Jokyung” (78 cm, 8.2 cm, 776, 46.6 g, respectively). “Hwanggeumal” displayed stronger winter hardiness than “Jokyung”, and was susceptible to powdery mildew (PM) and fusarium head blight (FHB). The average grain yield in the advanced yield trial (AYT) was 6.20 MT/ha, which was 11% more than “Jokyung”. In the regional yield trial (RYT) it was 5.13 MT/ha in upland and 4.77 MT/ha in paddy field, which were 16% and 13% less than “Jokyung”, respectively. “Hwanggeumal”s flour yield (71.4%) and flour lightness (91.82) was similar to that of “Jokyung”, while the protein content (14.0%), gluten content (10.3%), and SDS-sedimentation volume (60.3 ml) were higher than that of “Jokyung”. These results display that the “Hwanggeumal” dough strength of flour is stronger than “Jokyung”. High molecular weight gluten subunit (HMW-GS) composition is Glu-D1d (5+10), the granule-bound starch synthase (GBSS) composition are Wx-A1a, Wx-B1b, and Wx-D1a, and the composition of puroindolines are Pina-D1a and Pinb-D1b (Registration No. 9173).

Powdery mildew (Blumeria graminis f. sp. tritici) significantly affects wheat yield and flour quality. Plant resistance to powdery mildew has been investigated for decades, and numerous resistance genes and quantitative trait loci (QTLs) for molecular markers have been discovered. In Korea, powdery mildew occurs initially in spring, due to frequent rain and low temperatures, becoming severe during the harvest season. In Korea, systematic monitoring and quantitative and qualitative impact assessments of powdery mildew outbreaks have never been conducted properly. Herein, the lifecycle of powdery mildew, resistance genes, QTLs, and selection markers in wheat were examined to elucidate powdery mildew resistance, develop resistant varieties, and genetic markers suitable for the domestic environment.

Fusarium head blight (FHB) is a severe disease of wheat, mainly caused by Fusarium graminearum, which greatly reduces wheat production and directly affects human and animal health due to the mycotoxins produced in wheat grains. To develop high-quality, stable yields, and mycotoxin-free crop, it is essential to first understand the genetic basis of wheat FHB-resistance, and to design molecular markers facilitating the selection of FHB-resistant varieties. However, despite extensive global research efforts, genetic research and marker development for the selection of FHB-resistant varieties, in Korea, are insufficient. Here, we summarize recent studies on FHB-resistance genes, resistance resources, quantitative trait locus analysis, and genome-wide association studies to enhance our understanding of FHB and the breeding of FHB-resistant domestic wheat cultivars.

Wheat (Triticum aestivum L.) is one of the world's three staple crops and accounts for approximately 20% of the total calories consumed by the world's population. It is known that wheat is a difficult crop to introduce foreign genes into, having a large genome (16 Gb) containing three highly related subgenomes (AABBDD). Owing to the low transformation efficiency of wheat, it is difficult to apply new technologies such as genome editing and basic research based on molecular biology, such as the discovery of useful genes and functional analysis. Recently, the completion of a wheat genome map by the International Wheat Genome Sequencing Consortium (IWGSC) and the development of a stable and reproducible wheat transformation system have accelerated research regarding the expression and control of useful genes. In this review, we introduce in detail the recently developed highly efficient Agrobacterium-mediated wheat transformation system and its applications in plant biotechnology, such as RNA interference (RNAi), overexpression, and gene editing using this system.

Low-temperature damage at the seedling stage is one of the most significant natural obstacles to wheat’s growth. In domestic wheat breeding programs, the selection of cold-tolerant varieties is crucial for the development of superior wheat varieties. Traditionally, the extent of damage caused by freezing wheat is estimated through visual observation. In this study, we compared the RGB image analysis method with conventional visual evaluation and chlorophyll content analysis methods to determine if this method could accurately quantify the cold tolerance discrimination of wheat in the field. First, single-leaf-level RGB image analysis revealed a pattern similar to dead leaf ratio and chlorophyll content in three grades of freezing injury. Next, we compared the significance of plant-level RGB image analysis. The greenness index by RGB image analysis showed a higher correlation with dead leaf ratio by visual evaluation. Finally, 40 wheat varieties were planted in the field and wheat canopy images were collected at the seedling stage after wintering. There was a high correlation between the greenness index and the visual evaluation. However, there was no correlation between dead leaf ratio and visual evaluation or greenness index as determined by RGB image analysis. These findings suggest that using RGB image analysis rather than visual evaluation can be useful in assessing freeze damage in wheat fields.

To improve the seed purity management system of Korean wheat cultivars, 50 Korean wheat cultivars were subjected to chemical assays for grain color, genotyping of grain weight-related genes, and grain image analysis. The tested cultivars were primarily classified by NaOH and ninhydrin tests as white (26%) and red (74%) cultivars, as well as high PPO activity (48%), and low PPO activity (52%) cultivars, respectively. The allelic variations of Tamyb10 gene revealed Tamyb-A1a/Tamyb-B1a/Tamyb-D1a as the major allelic combination in white wheat and five different Tamyb10 genotypes (i.e., aba, abb, baa, bba, and bbb) in red wheat. Those cultivars with high PPO activity possessed the Ppo-A1a/Ppo-B1b/Ppo-D1b genotype, while those with low PPO activity possessed the Ppo-A1b/Ppo-B1a/Ppo-D1a genotype. In the grain image analysis, long grain cultivars displayed increased grain width, circularity, and area. Based on cluster analysis of grain traits, the Korean wheat cultivars were classified into two groups - 1) large red grain cultivars released before 2000, and 2) small red grain cultivars and white wheat cultivars released after 2000. Further research is required to determine the effects of grain filling conditions on the grain characteristics of Korean wheat cultivars and to develop efficient and reliable molecular markers for an improved seed purity management system.

This study aimed to develop an agarose gel-based multiplex PCR assay using sequence-tagged site (STS) and simple sequence repeat (SSR) markers that can differentiate Korean wheat cultivars. Forty-nine Korean wheat cultivars were primarily classified based on seed coat color into red (36) and white (13) groups. Red wheat cultivars were further differentiated by three multiplex PCRs using molecular markers for Ppo-A1/Vrn-D1a/Rht-B1b, Glu-A3ac/TaCwi-A1b/Lr34, and Glu-A1ac/Glu-B1b/KWSM003/TaSE96. Similarly, white wheat cultivars were further differentiated using two multiplex PCRs using the molecular markers for Ppo-A1/Vrn-D1a/Pina-D1a and Ppo-B1/Glu-B3h. A multiplex PCR assay using molecular markers for Glu-A1b/Glu-D1d/Wx-B1 was developed to differentiate four Korean wheat cultivars used as government certified seeds: Baekkang, Hwanggeumal, Keumkang, and Saekeumkang. A multiplex PCR assay using molecular markers for Glu-B3h and Pin-D1a was used for colored wheat cultivars, Arijinheuk, Ariheuk, and Chinese colored wheat. The multiplex PCR assays developed in this study can provide useful molecular tools for differentiating Korean wheat cultivars, developing wheat seed management systems, and guaranteeing wheat seeds in Korea.

Globally, wheat (Triticum aestivum) is a major food crop for humans with no regional restrictions. However, it is still difficult for Korea to achieve self-sufficiency owing to production limitations. Moreover, food security is unstable owing to the unpredictable climate and unstable international economy. Pre-harvest sprouting (PHS) is among the factors that occurs frequently due to irregular climates, and damages the value of wheat. In this study, RNA-seq was conducted on PHS-treated samples (for Korean representative cultivar ‘keumgang’) and PHS-resistant mutation line ‘Jeonju 377ho’. Gene functional annotation and DEGs analysis were performed using 234,131,980 mapped reads. Associated transcripts were analyzed using Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and were mainly used to search for genes associated with ATP synthesis and starch and sucrose metabolism related to seed germination and seed dormancy. Candidate DEGs were compressed through cluster set analysis, and gene expression was conducted to search for genes related to seed germination and dormancy to explain them in greater detail based on biological and chemical mechanisms.

Wheat (Triticum aestivum) is one of the three major food crops, along with rice and corn, and is the second most consumed crop after rice in Korea. However, the domestic production of wheat is insufficient, and the self-sufficiency rate is recorded in single digits. As wheat has a large genome size of 17 Gbp, and contains many repeated nucleotide sequences, it is difficult to conduct breeding studies and genome-based breeding lags behind that of other crops. To overcome the above challenges, we constructed a wheat core collection using simple sequence repeat markers that are suitable for the domestic cultivation environment with excellent reproducibility. Genetic diversity and population structure were analyzed using a core collection. Agricultural traits were evaluated in the Korean wheat core collection. Single marker analysis was correlated with 21 agricultural traits to identify potential molecular markers. These results may be useful for wheat breeding programs in the precision breeding era.

Wheat transformation was first initiated in 1992, and several studies were conducted to increase its efficiency; however, a very low probability of less than 0.3% was achieved. In 2011, the EU Commission announced a new plant breeding technology that modifies the DNA of seeds and plant cells to develop new varieties with desired characteristics. With the commercialization of the CRISPR/Cas9 technology, a site-directed nuclease technology, the possibility of its application in agriculture has increased with the rapid development of the technology. Recently, genome editing studies have been conducted in wheat, and they have been used for the functional analysis of genes related to various agricultural traits. The wheat full-length genome information was released in the form of a draft sequence in 2018, belatedly in comparison to other crops owing to allohexaploidy and a large genome (17 Gb) size. The recent pre-harvest sprouting resistance wheat breeding material developed in Japan suggests that it is possible to rapidly develop breeding materials through precision breeding technology. Finally, it is necessary to systematically achieve the goal of optimizing agricultural traits of crops through precise breeding technology to increase the breeding accuracy of allohexaploid wheat and rapid genetic fixation using the reduction in generation technology.

This study was conducted to investigate the effect of starch properties on the texture of cooked noodles from Korean wheat. The genetic composition of GBSS I (granule bound starch synthase I, called waxy protein) and puroindoline, which affect the amylose content and kernel hardness, was also evaluated. Waxy wheats carrying Wx-1 null alleles showed clearly different starch properties, high swelling power, pasting viscosity, breakdown and paste clarity, unsuitable texture of cooked noodles, and low hardness and springiness. Two partial waxy soft wheats carrying single or double null alleles at the Wx-1 locus gene, and Pina-D1a and Pinb-D1a alleles exhibited a softer and higher elasticity texture of the cooked noodles than Korean wheats carrying wild-type Wx-1 null alleles. There were no significant differences in the starch properties and texture of cooked noodles according to the puroindoline composition. A principal component analysis showed a strong negative relationship between the amylose content and starch swelling power, and these traits also improved the springiness and cohesiveness of the cooked noodles prepared from non-waxy Korean wheat. Joongmo2012, a double null partial waxy wheat, showed higher starch swelling power and springiness of the cooked noodles than other non-waxy Korean wheats.

A new winter wheat (Triticum aestivum L.) cultivar ‘Baekkang’ was developed by the National Institute of Crop Science (NICS) and Rular Development Administration (RDA) in 2015. Its heading date was April 23, and its maturity date was June 3, similar to that of ‘Keumkang’. ‘Baekkang’ had a shorter culm length (75 cm), longer spike length (8.0 cm), more spikes per m² (703), and more 1,000-grain weight (47.5 g) than those of ‘Keumkang’, which were 76 cm, 7.6 cm, 631, 46.4 g, respectively. ‘Baekkang’ was not a winter hardy crop and is susceptible to powdery mildew. However, it has moderate resistance to fusarium head blight. The average grain yield in the advanced yield trial was 5.5 MT/ha, 20% more than ‘Keumkang’. In the regional yield trial, this average yield was 5.1 MT/ha upland and 5.2 MT/ha in the paddy field, which were 10% and 18% more than that of ‘Keumkang’, respectively. Baekkang’s flour yield (71.2%) and flour lightness (92.40) showed similarities to those of ‘Jokyung’. ‘Baekkang’ also showed a higher protein content (12.4%), gluten content (10.1%), and SDS-sedimentation volume (60.0 ml). These results showed that the ‘Baekkang’ flour’s dough strength was greater than that of ‘Jokyung’. Baekkang’s high molecular weight gluten subunits composition was Glu-D1 (5+10), granule-bound starch synthase composition was Wx-A1 (a), Wx-B1 (a), and Wx-D1 (a), and puroindoline composition was Pina-D1(a) and Pinb-D1(b) (Registration No. 6966).

The National Agrobiodiversity Center of the RDA, Korea, has more than 22,700 accessions of global wheat genetic resources, including Korean wheat cultivars and landraces. Despite the numerous efforts to develop high-quality, hard winter wheat, the employment of new genetic resources into Korean wheat breeding programs is still hampered by the different growing environments. To overcome this limitation, 200 germplasms that were screened using the Genebank Management System (GMS) were evaluated in three different regions in Korea. In the 2018–2019 trial, 55 lines that showed superior field performance and high protein content were selected from among the 200 germplasms. These lines were re-evaluated in the 2019–2020 trial, and 24 lines that had suitable traits for growth, grain yield, and grain protein content in three locations were finally selected. These winter wheat germplasms also showed high yield stability throughout the three different environments in Korea. Preliminary screening using GMS information, consecutive regional tests, and quality tests could be effective procedures for the development of hard winter wheat in Korea. Therefore, introduction breeding could be a favorable breeding method aiming to improve quality, where useful genetic resources are limited.

This study was performed to evaluate the characteristics of wheat flour and sourdough bread quality of five Korean bread wheat cultivars, hard red winter wheat (HRW), and T55 (a French commercial wheat flour). Among the cultivars assessed, the protein and gluten contents and SDS-sedimentation values of Joongmo2008 were the highest, Keumkang were similar to those of HRW, and those of the Baekkang, Jokyung, and Hwanggeum were similar to those of T55. Joongmo 2008 and Keumkang had glutenin contents similar to those of HRW and T55, whereas Baekkang and Hwanggeum had higher HMW-GS (high molecular weight-glutenin subunit) and lower LMW-GS (low molecular weight-glutenin subunit) contents than HRW and T55. The α+β gliadin contents of Jungmo2008 and Keumkang were higher than those of other varieties and similar to those of HRW, whereas the γ- and ω-gliadin contents of Baekkang and Hwanggeum were similar to those of T55. Mixolab analysis revealed that Joongmo2008 and Keumkang had water absorption and kneading characteristics similar to those of HRW, and that Baekkang, Hwanngeum, and Jokyung showed characteristics similar to those of T55. Campagne and baguettes prepared using Korean wheat flour were similar in appearance to those prepared using T55 or HRW, the bread volume of campagne bread was smaller than that of T55, and the volume of baguettes were similar to that of T55. Joongmo2008 showed a higher bread volume than other Korean wheat cultivars, which was similar to that of HRW. The quality of sourdough bread prepared from Korean wheat flour was similar to that made with commercial flour, although the bread prepared using Joongmo2008 was found to be superior to that prepared using the flour of other Korean wheat cultivars.

The regeneration rate of plantlets cultivated via tissue culture is an important factor for wheat transformation. Similar to other monocotyledons, the most efficient tissue culture materials for wheat are immature embryos. However, stable year-round production of immature embryos is not possible in the field where various stress factors co-exist. In this study, we investigated the generation and subsequent plantlet incident rates of callus induced from immature embryos obtained from different sowing times in 2020 and compared these among wheat cultivars. We found that the rates of regeneration and plantlet incidence obtained using immature embryos of the Ariheuk cultivar were higher than those of other domestic cultivars, and that the tissue culture efficiency was similar to that of Bobwhite, which has been established as a cultivar with excellent transformation efficiency. Furthermore, the Baekkang cultivar showed high tissue culture efficiency only when sown from early to mid-March, whereas Keumkang showed higher tissue cultivation efficiency only by sowing in mid- and late February. Among the five cultivars assessed in this study, Jopum showed the lowest tissue culture efficiency. It is anticipated that the findings of this study will contribute to enhancing the transformation efficiency of domestic wheat varieties.

Kernel weight is a vital trait for selecting high-yielding wheat in breeding programs. We evaluated the thousand-kernel weight (TKW), test weight (TW), grain length (GL), grain width (GW), grain thickness (GT), and grain roundness (GR) of 41 Korean winter wheat cultivars over a period of 4 years. Correlation analyses revealed that TKW was positively correlated with GL (r=0.76***), GW (r=0.85***), and GT (r=0.84***), whereas TW was negatively correlated with GL (r=-0.38*) and GT (r=-0.31*). Allelic variation was analyzed for 13 kernel weight-related genes/loci (TaCwi-A1, TaCWI-4A, TaCWI-5D, TaGW2-6A, TaTGW6-A1, TaTGW-7A, TaGS1a, TaSus1-7A, TaSus1-7B, TaSus2-2B, TaCKX6-D1, TaCKX6a02-D1, and TaSnRk2.3). Significant associations between the allelic variation and kernel traits were identified in TaCWI-4A (TW, GL, and GR), TaCWI-5D (TKW), TaGW2-6A (TKW, GL, GW, and GT), TaSus2-2B (TKW, GL, GW, and GT), and TaGS1a (TW). In contrast, we detected no significant association between the allelic variation of TaCwi-A1, TaTGW6-A1, TaSus1-7A, and TaSus1-7B and variations in kernel traits. Also, TaTGW-7A, TaCKX6-D1, TaCKX6a02-D1, and TaSnRK2.3 were found to be monomorphic. The four loci TaCWI-4A, TaCWI-5D, TaGW2-6A, and TaSus2-2B showed significant phenotypic differences, a totalof 10 different haplotypes (AC1-AC10) were observed at four loci among the Korean wheat cultivars. Cultivars with the AC1 haplotype exhibited significantly higher TKW than those with the AC8 haplotype, which comprises alleles for high TKW at all four loci, indicating that additional loci controlling kernel weight might be present in the high TKW cultivars.