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 (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.

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).

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.

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.