In Asia, where climate change is increasing the damage caused by cold stress, it is crucial to cultivate varieties with enhanced cold tolerance. In this study, the Tongil variety ‘Hanareum2’ was crossed with the Japonica variety ‘Unkwang’ to improve plant growth ability at low temperatures during the seedling stage. This led to the development of 234 recombinant inbred line (RIL) populations, and a linkage map was constructed using 249 single nucleotide polymorphism (SNP) markers. The RIL populations were transplanted to the field one month earlier than the standard transplanting period, and plant height (PH), leaf number (LN), and dry weight (DW) were measured to identify quantitative trait loci (QTL) associated with plant growth ability at low temperatures during the seedling stage. QTLs related to cold tolerance, particularly those carrying the ‘Unkwang’ allele, were identified in the PH and DW traits. For PH, the QTLs qPH1, qPH5, and qPH8 were located on chromosomes 1, 5, and 8, respectively. Regarding DW, the QTLs qDW1, qDW8, and qDW9 were identified on chromosomes 1, 8, and 9. For the LN trait, qLN3 carrying the ‘Hanareum2’ allele was located on chromosome 3. If the identified QTLs are utilized, they can be incorporated into breeding programs for plant growth at low temperatures during the seedling stage.

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.

Pear (Pyrus spp.) is an economically important fruit tree that grows extensively worldwide. To facilitate the identification of agronomically important traits and provide new information for genetic and genomic research concerning this fruit tree, a high-density genetic linkage map of pear was constructed using 178 F₁ populations derived from a cross between ‘Manpungbae’ and ‘Oharabeni’. Single nucleotide polymorphisms (SNPs) detected by genotyping-by-sequencing (GBS) and simple sequence repeats (SSRs) developed from pears were analyzed to construct a genetic linkage map. SSR markers were used to locate the corresponding chromosome number for each linkage group (LG). A total of 1,807 GBS-SNPs and 41 SSRs were anchored to the integrated genetic linkage map. Seventeen LGs were identified, covering a genetic distance of 1,519.4 cM with an average marker density of 0.87 cM. The lengths of the LGs ranged from 70.9 cM (LG 14) to 160.4 cM (LG 15). Each LG had SSR markers from 1 to 5, except for LGs 7, 8, and 9. Our integrated genetic map of pear could be used as a basic frame map for comparative analysis of genomic structure between different pear research groups.

Rice production is largely affected by various environmental conditions such as cold, heat and flooding. Here, to identify cold tolerant QTLs at seedling stage in rice, we generated RIL population derived from a cross between Hanareum 2 and Unkwang which are a highly cold sensitive and cold tolerant, respectively. We observed cold phenotype of this population in the growth chamber conditions and natural field conditions. For observation of cold tolerant phenotype of RIL population in the growth chamber, we treated cold stress (5~13°C) for 14 days and recovery for 4 days. When we examined the phenotype of RIL in the field conditions, temperature range in the field conditions was about 6 to 25°C in 2015~2016. We named QTLs as Seedling Cold Tolerant (SCT) in growth chamber and Cold induced Yellowing Tolerant (CYT) in the field, respectively. Three QTLs for SCT and 5 QTLs for CYT were detected on chromosome 1, 6, 7, 8, 10, 11 and 12. Among these QTLs, qSCT12 on chromosome 12 showed 26.3 LOD score with 25.5% of phenotypic variation. When qSCT11.1 and qSCT12 were combined, cold tolerant was most strongest in our experimental conditions. qCYT10 on chromosome 10 was identified in field experiment on both 2015 and 2016. These results may provide useful information for a marker-assisted breeding program to improve cold tolerance in rice.

Seed dormancy is an important adaptive mechanism to protect seeds under the unfavorable environments. Unlike to wild type species, the seed dormancy trait of cultivated crops has been weakened by breeding programs during the domestication period. Weak seed dormancy often causes preharvest sprouting (PHS) problem in many cereal crops that result in significant economic loss. The seed dormancy is a quantitative trait loci (QTL) controlled by multiple genetic and environmental factors. So far, many QTLs for seed dormancy have been identified from rice and wheat as well as in the model plant Arabidopsis. Unveiling of QTL genes and complex mechanisms underlying seed dormancy is accelerated by the rapid progress of crop genomics. In the present study, we reviewed current status of research progress on the seed dormancy QTLs and correlated genes in Arabidopsis and cereal crops.