Pears (Pyrus spp.) are economically important fruit trees grown extensively world-wide. To identify QTLs related to key agronomically important fruit traits, we conducted QTL analysis using an interspecific 178 F₁ populations derived from a cross between ‘Manpungbae’ and ‘Oharabeni’. Phenotyping data, including fruit weight, fruit length and diameter, fruit shape index (FSI), soluble sugar content, fruit firmness (FF), and titratable acidity (TA) were investigated from 2016 to 2018. Using the previously constructed genetic linkage map together with the three-year phenotypic dataset, we detected 14 significant QTLs associated with the control of fruit weight, fruit length and diameter, FSI, FF, and TA on linkage groups 3, 10, 11, 12, and 13. These findings provide a useful resource for advancing genetic and genomic studies in pears and will aid breeding efforts to improve major fruit traits.

To diversify the grain quality characteristics of Korean varieties of japonica rice (Oryza sativa japonica), recombinant inbred lines were developed from a cross between the Korean cultivar “Boramchan” and the tropical japonica cultivar “Pecos” from the United States. Quantitative trait locus (QTL) analysis was performed to investigate the traits related to grain quality. Sixteen traits were evaluated, including five related to grain appearance, six associated with pasting properties and glossiness of cooked rice, and four related to eating texture. QTLs were detected on chromosomes 3, 5, 6, and 10, and candidate genes, including Hd1, qLTG3-1, GW5, and qGS10 were identified. The heading date-related gene Hd1 was associated with the following traits: head rice (HR), opaque rice (OR), damaged rice, pasting temperature, peak viscosity (PV), breakdown viscosity (BD), and glossiness. Most quality-related traits were influenced by allelic variation at Hd1, and the Hd1⁺ allele from “Boramchan”, which delays heading, positively affected both grain appearance and eating quality. The low-temperature germinability gene qLTG3-1 was identified as a candidate gene for broken rice and several pasting properties, including trough, final, and breakdown viscosities, and was shown to influence pasting characteristics depending on allelic variation. The grain shape gene GW5 was a candidate gene for HR and whiteness, whereas qGS10 was associated with OR, PV, BD, and setback viscosity. The GW5⁺ and qGS10^P alleles, derived from the slender grain shape of “Pecos,” contributed positively to both grain appearance and eating quality, indicating their potential as favorable alleles for improving grain shape and diversifying quality traits in Korean japonica rice. The results of this study demonstrate that key agronomic trait-related genes, such as heading and grain shape, significantly affect various quality-related traits, highlighting the potential of introducing and combining novel alleles to enhance grain quality in Korean japonica rice.

Genetically modified (GM) crops have been developed to enhance various agronomic traits and increase the production of functional compounds. In the present study, the major agronomic characteristics of protopanaxadiol (PPD)-enriched GM rice, which was developed by introducing dammarenediol-II synthase (PgDDS) and protopanaxadiol synthase (CYP716A47) genes from Panax ginseng into Oryza sativa cv. Dongjin, were evaluated. The stability of the introduced genes was confirmed using PCR and immunostrip tests, which showed consistent expression across multiple generations (T5-T7). Agronomic traits, including days to heading, culm length, panicle length, tiller number, and grain weight per plant, were compared between GM rice and its non-GM counterpart, Dongjin rice. No significant differences were observed for these traits, indicating that genetic modification did not affect the overall plant growth. However, seed morphology analyses revealed that PPD-enriched GM rice had significantly longer brown rice grains. In contrast, other seed traits remained within the natural range of commercial rice varieties. Furthermore, PPD was consistently detected in GM rice, whereas it was absent in non-GM Dongjin rice. These findings suggest that PPD-enriched GM rice maintains a stable agronomic performance while successfully accumulating PPD, supporting its potential as a functional crop. However, further research is required to evaluate its environmental impact, food safety, and efficacy as a functional food source.

‘Chamdongjin’ is a rice cultivar with a distinctively large grain size and good palatability, similar to ‘Sindongjin,’ which is a mega-cultivar in Korea. ‘Younghojinmi’ is a rice cultivar known for having the highest taste value among premium quality cultivars. In this study, we conducted quantitative trait loci (QTL) analysis of quality-related traits using recombinant inbred lines (RILs) derived from a cross between ‘Chamdongjin’ and ‘Younghojinmi’ to elucidate their genetic interactions. We analyzed 20 traits, including protein content, amylose content, glossiness of cooked rice, 7 traits related to grain appearance, 6 traits related to pasting properties, and 4 traits related to texture. Quality-related QTL were primarily detected on chromosome 3. In particular, GS3, one of the candidate genes for QTL, significantly influenced quality by affecting 14 different traits, including appearance traits such as head rice and the texture of cooked rice. Furthermore, RILs with the gs3 allele, which exhibited the large grains of ‘Chamdongjin,’ showed a lower protein content and higher amylose content than RILs with the GS3 allele. These lines also had lower head rice percentages and higher percentages of whiteness, opacity, and broken rice, indicating an inferior appearance quality. In terms of pasting properties, RILs with the gs3 allele showed a lower pasting temperature, peak viscosity, and breakdown, but a higher setback than RILs with the GS3 allele. Although the gs3 allele did not affect the glossiness, hardness, or toughness of the cooked rice, it resulted in higher adhesiveness and stickiness. Allelic alteration of the preharvest sprouting gene qLTG3-1 was found to affect seven quality-related traits, including pasting properties. Genes related to heading date (Hd18), culm length (SD1), and tiller number (OsTB1) were also associated with quality-related QTL. Alterations in the alleles of these genes caused variations in quality-related traits. Our identification of the association between quality-related traits and key agronomic genes is expected to support the effective development of rice cultivars with improved quality.

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 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.

Recently, crossbreeding between Asian rice (O. sativa) and African rice (O. glaberrima) has become an important solution for hunger refugees and food problems in Africa by improving grain yield. O. glaberrima exhibits important traits such as stress tolerance, and genetic diversity evaluation and structural analysis of agronomic traits have been conducted. In this study, 11 yield-related agricultural traits were analyzed in 45 lines of O. sativa and 28 lines of O. glaberrima under Korean climatic conditions. Through cluster analysis using the investigated yield-related traits, O. sativa and O. glaberrima were grouped into clusters by characterizing the remaining traits, except for the number of spikelets, grain width, and grain thickness. The number of spikelets was highly influenced by the environment and had the greatest variation, whereas grain width showed the least variation. In addition, rice yield components are quantitative traits, and in breeding to improve yield, it is important to analyze the interaction of agricultural traits and the influence of the environment to maintain an optimal balance and improve plant potential. Although O. sativa was found to exhibit different agricultural traits depending on its ecotype, it still belonged to the same group when clustered. The results of this study provide basic information on the yield-related agronomic characteristics of O. sativa and O. glaberrima under Korean climatic conditions, suggesting that O. glaberrima can be used as breeding material to diversify Korean rice genetic resources.

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.

The
objective
of this study is to assess the impacts of additional N fertilization on agricultural traits, flour characteristics, and noodle quality of O-free, a variety known for reduced allergy effects. With increasing fertilization rates, both culm length and spike length showed an increase, accompanied by a rise in grain nitrogen removal due to higher protein content in the grains. The leaf area index (LAI) reached its peak during the booting stage, while the canopy LAI peaked at 21 days after flowering (21-DAF). Although LAI of plant was higher in the treatments with additional nitrogen (N1 and N2) compared to the control (N0), there was no significant difference observed in canopy LAI. Chlorophyll fluorescence values were highest at 21-DAF and lowest at 35-DAF, regardless of the fertilizer rate. The dry weight of leaves and stems was highest at 7-DAF in N0 and N1 treatments, but at 21-DAF in N2 treatment. During grain filling, the nitrogen content decreased in leaves and stems, while it increased in the grains. With higher fertilization rates, there was an increase in the moisture content, flour color value, protein content, and sedimentation value of flour, whereas the particle size of flour decreased. Dough extensibility, mixing time, and protein strength showed an increase as the fertilizer rate increased, but dough stability decreased. The control exhibited the highest starch gel stability and aging, while N1 had the lowest starch swelling. Cooked noodles demonstrated increased brightness, thickness, and hardness with increasing fertilizer rate, but elasticity and viscosity showed no significant changes.

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.

To compare agronomic and seed traits of 135 common bean landraces originating from Korea, Bulgaria, and El Salvador, we evaluated 20 morphological traits and performed principal component analysis (PCA). In the PCA, the first and second principal components accounted for 55.15% and 15.97% of the total variance, respectively. The first component showed a strong positive correlation with seed size and 100-seed weight, whereas the second component produced a strong negative correlation with days to flowering and days to maturity, indicating that these traits may explain the differences between landraces originating from different countries. Landraces from Korea showed higher variation in days to flowering and days to maturity; those from Bulgaria produced larger and heavier seeds; those from El Salvador produced smaller and lighter seeds and flowering and maturity occurred earlier. In addition, the landraces from El Salvador had relatively lower diversity compared to those from other countries, as they were grouped within a small cluster in the PCA. These evaluation results may provide important information for selecting breeding materials, and diversity analyses of landraces from different countries provide information for securing genetic resources.

In Korea, black soybeans are traditionally consumed after cooking with rice to supplement protein and oil which are lacking in rice. Seed cooking quality including seed traits after cooking with rice, which is important for consumers, were so far not comprehensively considered during the process of breeding. In this study, we first evaluated seed quality after cooking with rice, we tested the correlation between seed cooking quality and seed water absorption ratio, and we attempted to identify the Quantitative trait locus(QTL)/gene using two recombinant inbred line (RIL) populations, i.e., Daepung × Socheong2 and Daepung × Ilpumgeomjeong. Based on phenotype and correlation analyses, the main factors affecting the hardness of soybeans cooked with rice may differ between RIL population. In the Daepung × Socheong2 RIL population, one QTL associated with seed hardness after cooking with rice was identified on chromosome 11, and Glyma.11g049600, encoding peroxidase, is proposed as a candidate gene. In the Daepung × Ilpumgeomjeong RIL population, two QTLs associated with seed hardness after cooking with rice were identified on chromosomes 7 and 19, one QTL related to seed water absorption on chromosome 3, and Glyma.19g092600 encoding pectin methylesterase inhibitor are proposed as candidate genes. This is the first study on soybean cooking quality after cooking with rice, and the locations of four related QTLs were identified. The results will be of use for future development of high-quality black soybean varieties with high consumer preference using molecular breeding methods.

Plant germplasm is a part of living genetic resources, including seeds and plant materials, such as roots, leaves, and stems, and should be conserved and managed to maintain ecological biodiversity and to consistently generate the product and supply food crops. Plant germplasm can be categorized based on various genetic traits such as race, and clustering based on similar genetic traits is an efficient method for managing large numbers of germplasms. Therefore, we developed an algorithm, termed cacGMS (Clustering Analysis for Categorical genetic traits of germplasms in Genebank Management System), using categorical variables which statistically differentiate the datatype of genetic traits such as seed-coat color, seed shape, and flower color. Briefly, using Newman’s modularity method, cacGMS combines the hierarchical clustering algorithm using the Ward2 method and representative-based algorithms such as K-medoids, and it regroups all germplasms using germplasm core sets. We tested cacGMS using 2,378 pepper germplasms with 46 different categorical genetic traits, and it exhibited better performance than the hierarchical and K-medoids algorithms for the average distance among clusters (0.4534) and entropy (1.2672). Moreover, cacGMS showed better performance in terms of threshold (from 15 to 30) for genetic traits than other algorithms and provided similar results in a test run using tomato germplasm. From these results, we expect that cacGMS will be a useful tool for managing each group with numerous plant germplasms and facilitate the analysis of other studies, such as analysis of representative characteristics of clustered germplasms and of correlations among germplasms in a particular cluster.

In this study, composition and agronomic traits, including yield-related traits, were investigated and compared among 35 Korean landrace germplasm for two years (2019 and 2020). The contents of 12 isoflavones were measured using high-performance liquid chromatography, and agronomic trait data were collected according to the Rural Development Administration criteria. Comparing isoflavone composition between the two years, all isoflavones, except glycitein, were generally higher in 2019. The values of yield-related and major agronomic traits decreased in most accessions in 2020. ANOVA showed highly significant differences (p<0.001) in genotypes, years, and genotype-by-year interaction for all isoflavones, the number of pods per plant, and 100-seed weight. The number of seeds per pod, days to flowering, and days to maturity also showed significant differences among genotypes, as well as between the two years. Correlation analysis revealed that daidzin and genistin were positively correlated with their malonylated form. Malonyl daidzin was also positively correlated with malonyl genistin levels. The accessions with the least variation in the total isoflavone content were IT 153844 (907.5 µg/g, 898.6 µg/g) and IT 252252 (663.2 µg/g, 636.4 µg/g). Some of the evaluated landraces will be a promising genetic source for developing soybean varieties with high levels of environmental stability in isoflavone content and agronomic traits.

Understanding plant morphological and seed characteristics is an essential step for the utilization of genetic resources to improve targeted traits in soybean breeding programs. The purpose of this study was to evaluate the agronomic traits and seed pigments of 469 black soybean germplasms with green cotyledons to identify useful resources using multivariate analyses, correlation, principal component analysis (PCA), and cluster analyses. The results showed that the range of flowering days from planting were 37.7-71.5 days, harvesting days from planting were 112.3-153.0 days, plant height was 49.6-151.6 cm, and 100-seed weight was 9.1-49.3 g. According to the correlation analyses with agronomic traits, flowering and harvesting days were positively correlated with the plant height, number of nodes, and number of branches. Additionally, it was found that the chlorophyll a and total chlorophyll content had the greatest effect on the green color of the cotyledon. Based on the PCA, 13 quantitative traits were compressed into three components. The first three principal components accounted for 82.5% of the total variance. In this study, black soybean germplasms with green cotyledons were divided into four clusters by the K-means cluster analysis (non-hierarchical procedure), based on the PCA. The cluster analysis showed that chlorophyll a and plant height had a significant effect on the clustering of the black soybean germplasms used in this study. This study provides opportunities to easily select useful genetic resources for the development of new black soybean cultivars.

Hypoxia caused by water seeding of rice inhibits germination and often leads to serious problems in seedling establishment and early growth. To solve this problem, it is necessary to develop rice cultivars that can stably germinate and grow under anaerobic environments. In this study, we performed QTL analysis on anaerobic germination (AG) tolerance using 139 recombinant inbred lines (RILs) derived from a cross between Milyang23 and Gihobyeo, and identified two QTLs (qAG2.1, qAG2.2) on chromosome 2. The LOD scores at qAG2.1 and qAG2.2 were 3.30 and 5.31, respectively. The phenotypic variances explained by the QTLs were 9.19% and 14.99%, respectively. The japonica cultivar Gihobyeo provided alleles for AG tolerance at both QTLs. While the chromosomal location of qAG2.2 overlapped with previously identified QTLs for AG tolerance, qAG2.1 was detected in a locus that has not been reported previously. The RILs carrying favorable type alleles for the AG tolerance at both QTLs (qAG2.1 + qAG2.2) expressed 41.0% survival rate under the AG condition, which was significantly higher than those of the RILs carrying single QTL, qAG2.1 (22.0%) or qAG2.2 (26.2%). As the favorable alleles for the two QTLs found in this study derived from the japonica cultivar Gihobyeo, it is expected that they would accompany less linkage drag such as shattering and lodging compared to those derived from indica or landraces. The result of this study would provide useful information for improving AG tolerance of japonica rice cultivars that can be used for water seeding cultivation.

Oats are known for their abundance of quality proteins and lipids compared to those of other grain crops; they especially contain a large amount of good quality fibers, including β-glucan. The Korean domestic consumption of oats is rapidly increasing due to their high nutritional value. However, the research for functional food breeding material has been insufficient because oats have been focused on as feed. Therefore, this study aimed to evaluate the agronomic traits and important nutritional ingredients, including β-glucan, protein, lipid, fiber, and dietary fiber, of 142 oat germplasms from Korea, China, and Japan, which are maintained in the National Agrobiodiversity Center. In addition, the diversity by origin of the germplasms was analyzed based on their agronomic traits. For the agronomic characteristics, Korean oat germplasms were on average headed and matured earlier than the Chinese and Japanese ones. Seven accessions, including IT151107, were matured before mid-June, which makes double cropping possible in the Southern region of Korea. In the diversity analysis by origin based on quantitative agronomic traits, Korean oat germplasms were in the distinguished group compared to Chinese and Japanese germplasms. Oat germplasm had a wider range of main ingredients compared to that of Korean domestic oat cultivars. However, Chinese germplasms had a significantly higher β-glucan content, while Korean germplasms had significantly higher crude protein, crude lipid, and crude fiber contents, than did other germplasms from other origins. Dietary fiber contents showed no significant differences between origins. IT129802 (China), IT166594 (Korea), IT166584 (Korea), IT151108 (Korea), and IT129798 (China) showed the highest β-glucan, protein, lipid, fiber, and dietary fiber contents, respectively. These selected oat germplasms can be superior breeding materials for various functional and agronomic purposes.

This study was carried out to investigate the utilization value of legume crops collected in tropical and subtropical areas. We examined agronomic traits to assess domestic adaptability and evaluated useful components of foreign legumes. We used a total of 201 genetic resources of three legumes, consisting of 68 lentils, 72 chickpeas and 61 guars. The average number of days to flowering of the three legumes ranged from 56.7 to 60.8 days; the shortest in guar and longest in chickpea. The average number of days to growth of the three legumes ranged from the shortest 86.8 days in lentil, to the longest 163.9 days in guar. The maturation period of the three legumes lasted from the end of May until mid-September, based on sowing in March. However, the average yield of lentil was very low, ranging from 0.5 g to 30.6 g, with an average 16.4 g based on 10 plants per accession. The average 100 seed weight of the three legumes was 2.2 g for lentil, 22.9 g for chickpea, and 3.8 g for guar. The crude protein content ranged from 14.1% to 32.4% with an average of 20.4%, the highest for guar and the lowest for chickpea. The average crude oil content in the three legume crops was generally low, ranging from 0.8% in lentil, to 4.3% in chickpea. The average dietary fiber content in the three legume crops varied from 15.7% to 50.7%. Guar was the highest source of fiber, followed by chickpea (19.3%) and lentil (15.7%). From the agricultural traits analysis, chickpea and guar could grow domestically. However, lentil was difficult to flower and fruit normally during the warmer season after May. Therefore, lentil should be considered for late summer cropping during the cool season. The physicochemical properties of the three legumes seem to be useful as they are similar to, or better than, those of the control common bean.

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.

A doubled haploid (DH) lines derived from the cross between high-yielding japonica rice cultivars ‘Deuraechan’ and ‘Boramchan’ was developed to increase diversity of panicle and yield-related traits and select high-yielding lines. Panicle and yield-related traits of DH population consisting of 163 lines and 13 selected high-yielding lines were analyzed using correlation, principal component, and path analysis. Among panicle-related traits, number of spikelets on secondary rachis-branches (SRBs) was more highly correlated with and had more positive effect on number of spikelets (NS) than number of spikelets on primary rachis-branches (PRBs) per panicle. In the DH population, NS had the most positive effect on yield, whereas panicle number per hill (PN) was in the selected lines. PN was significantly positive correlated with ratio of ripened grain (RGG) in both case. The enhancement of ripening and increase of total spikelets number by increasing PN had more effect on yield than increase of total spiekelts number by increasing NS in the selected lines. Among 13 lines, four lines, AC60, AC152, AC156, and AC161 showed higher yield than Deuraechan (481 kg/10a) and Boramchan (558 kg/10a). Deuraechan exhibited panicle-weight type with low tiller and heavy panicles and Boramchan was slightly panicle-number type with more PN and higher RGG. Selected high-yielding lines showed medium characteristics of parents with improved yield potential. These elite lines could be utilized to develop high-yielding japonica rice.

Grain yield, agronomic traits, and correlation between genetic distance of 36 F₁ hybrids produced by half-diallel crosses using nine maize inbred lines were analyzed. In the analyses of F₁ hybrids and their mid-parent heterosis (MPH) for agronomic traits, grain yield showed highest MPH value of 156%. One-hundred kernel weight showed the lowest value of 7%. In addition, when genetic distance based on agronomic traits was estimated, parental inbred lines did not agree with their own pedigree. Therefore it had the limitation to estimate genetic distance using agronomic traits. In this study, 92 SSR markers were used to calculate genetic distance at DNA level. However we did not confirm their own pedigree of nine parental inbred lines. There was no correlation between grain yield and SSR markers. Therefore molecular marker selection was conducted in relation with grain yield by the step-by-step method using 92 SSR markers. The selected nine SSR markers showed a significant positive correlation (r²=0.703**) between grain yield and SSR markers. The correlations between the selected SSR markers and agronomic traits of ear length, ear width, plant height, and ear height were particularly showed positively correlated. The nine SSR markers selected in this study would help predicting heterosis and planning crosses for hybrids in maize breeding programs.

One hundred sixty four wheat (Triticum aestivum L.) lines expressing the long spike were developed by the National Institute of Crop Science, Rural Development Administration. Six of 11 genes showed allelic variation among 164 lines and they were highly related to yield traits containing spike and kernel number, kernel length, 1000-kernel weight and grain yield. Analysis of allelic variation of each gene showed high correlation between allelic variation and agricultural characteristics. Coefficient of correlation between culm length and spike length was the highest 0.436. The heading date of the lines expressed Vrn-D1 allele was late and the lines expressed Vrn-D1 allele had longer spike length and higher number of kernel per spike than other lines. There was no significant difference in agronomic characteristics of analysis of Vrn-B1. Ppd-D1b was related to heading date and higher number of spike/m². Ppd-D1a was corresponded to number of kernel per spike and 1000-kernel weight. Three haplotypes, Hap-L, Hap-6A-G and TaCwi-A1a, were related to 1000-kernel weight.