Gluten proteins in wheat grains are generally considered one of the most important factors in determining dough properties and bread quality. In this study, wheat protein quality characteristics were investigated in 607 varieties collected from seven countries grown in a South Korean wheat breeding field for two years. The average protein content was 12.2±1.86%, and the sodium dodecyl sulfate-sediment volume (SDSS) was 46.9±8.39 mL. HI-LINE had the highest protein content (18.3±0.35%) and SDSS (76.7±1.98 mL), while both NE 84557 and Iksan 374 showed small deviations in protein content and SDSS. Protein content and SDSS values were higher in Ax2*+By8 and By9+Dy10 combinations at Glu-A, Glu-B1, and Glu-D1 loci of high molecular weight gluten subunit (HMW-GS) than in other combinations. However, no difference in Glu-A3 and Glu-B3 loci in LMW-GS was observed. Furthermore, in HMW-GS, the composition of Glu-D1 Dy10 and Dy12 had a greater effect on protein quality than Glu-B1 By8 and By9 when the allele of Glu-A1 had Ax2*. Significant differences were found between Dy10 and Dy12 genes of the HMW-GS Glu-D1 and between protein content and SDSS, but not among others. These results suggest that Glu-D1 is extremely important for improving protein quality in HMW-GSs. As a result of this study, HMW-GS allele selection using functional markers, protein content, and SDSS investigation are expected to enable the development of varieties with high protein quality that are stable amid various environmental changes.

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.

Consumer demand for Triticale cultivars as a winter forage crop in Korea has been increasing because of its ability for high and stable yield. However, more than 10 years are required to develop new varieties with conventional breeding programs. A speed breeding system using long-day photoperiodic treatment has recently been suggested and applied in wheat and barley, but not in the triticale breeding program in Korea. To evaluate the availability of the established speed breeding system for triticale breeding programs in Korea, we used nine domestic triticale cultivars to investigate their growth characteristics under a 22 h photoperiod. The average days to heading (DTH) of the nine cultivars was 38 days, and Gwangyoung and Minpung showed the most delayed DTH at 42 days. Therefore, all nine triticale cultivars were able to shorten the growth duration under the tested photoperiod condition. One productive tiller and more than 10 seeds were obtained from each cultivar. The germination percentage was over 82% when the spikes were harvested 20 days after heading, dried, and chilled for a week to break dormancy. These results suggest that in Korea, the rapid generation advancement system with simple long-day photoperiodic treatment can be applied to triticale breeding programs to reduce the breeding time.

Rice doubled haploid (DH) lines derived from crosses of the indica cultivar 93-11 and japonica line Milyang352 were used in genetic mapping and QTL analysis studies of days to heading (DTH), an important trait that controls rice yield and biomass. QTL mapping was conducted using the inclusive composite interval mapping method. We used 234 single-nucleotide polymorphic markers in the whole-genome region, including 100 KASP markers and 134 Fluidigm markers, to construct a genetic map. DH populations were raised in Milyang, Korea, over three different periods. Two major DTH QTLs, qDTH3-1 and qDTH7, were detected under natural conditions in Milyang, and explained 14.88%~24.56% and 24.20%~37.39% of the phenotypic variation, respectively, in 93-11×Milyang352 DH populations. During three different rice cultivation periods, qDTH3-1 and qDTH7 were repeatedly detected with significant logarithm of the odds scores and phenotypic variability explained. The findings of this study will make a valuable contribution to breeding high-yielding and early-maturing rice in Korea.

AbstractThe high-molecular-weight glutenin subunit (HMW-GS) composition of wheat is the main factor controlling gluten strength related to bread baking quality. Reported molecular markers for HMW-GS were validated and selected for improved breeding efficiency in South Korean wheat breeding programs. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, lab-on-a-chip electrophoresis, sequence-tagged site (STS) markers, and Kompetitive Allele-Specific PCR were performed to re-evaluate the known HMW-GS of 14 wheat cultivars. Glu-A1b and Glu-A1c alleles were separated by the STS marker, UMN19, and KASP marker, namely Glu-Ax1/2*_SNP, at Glu-1 loci. At the Glu-B1 locus, Glu1-By8 and Glu1-By9 could be distinguished from Glu-B1b and Glu-B1c alleles by two STS markers, namely ZSBy8 and ZSBy9a, respectively. Glu1-Bx17 and Glu1-7^OE could respectively be separated from non-Glu-B1i and non-Glu-B1al alleles by cauBx642 and BX7^OE_866_SNP. The Glu-D1d allele, used to determine bread baking quality, could easily be distinguished from other alleles by Glu-D1d_SNP at Glu-D1 loci. Validated molecular markers in this study could therefore be used to select wheat lines for good bread baking quality in South Korean wheat breeding programs.

A speed-breeding system using photoperiod characteristics has recently been developed to reduce the entire growth period in wheat. In this study, the entire growth period of four Korean varieties was examined to investigate whether this speed-breeding system would be beneficial for our wheat breeding program. When four varieties were cultivated under a 22-hour light/2-hour dark cycle in a glasshouse, the number of days to heading of Jokyoung and Baekkang was 44 and 43, respectively, and the number for Keumgang and Joongmo2008 was more than 75. Around twelve seeds per plant were obtained from Jokyoung and Baekkang, and the seeds of these varieties completely germinated when harvested at 20 days after heading. These results suggest that this speed-breeding system can be a reliable method of reducing the growth period in Korean wheat breeding.

The rice recombinant inbred lines derived from Hanareum2 and Unkwang (HURILs) cross were used in genetic mapping and QTL analysis studies using the inclusive composite interval mapping (ICIM) method. In this study, we constructed the genetic map using 241 SNP markers based on the SNPs in the whole genome region between these varieties. As a result, the total genetic distance and average distances were 1,142 cM and 4.7 cM, respectively. Both heading date and plant height are important traits related to grain yield in rice. Twelve heading date QTLs were detected under natural condition in Korea. A major QTL qDTH3-2 for heading date and qCL1-2 for plant height explained 25.8~27.4% and 30.8~56.9% of the phenotypic variations in the HURIL populations. Four panicle traits, grain number (GN), panicle length (PL), number of panicle per plant (NPP), grain filling ratio (GFR) were evaluated for QTL effects in HURILs population during two years. Results showed that a total of twelve QTLs for GN, PL, NPP, and GFR were detected on chromosome 2, 3, 4, 6, 7, 8. A major QTL qGNP4 for GN was detected in HURIL populations with LOD score 7.7-19.3 and explained 6.7-17.69% of phenotypic variations. Twenty-five QTLs for the four traits TGW, GL, GW, and GT were identified in the HURIL populations for two years (2014~2015). The three QTLs, qTGW8, qGL8-2, and qGW8-2, shared the same interval between id8007093 and id8007764 on chromosome 8 with explained 4.8-4.1%, 4.2-6.8%, and 5.3-10.5% of phenotypic variations, respectively. Furthermore, two QTLs, qTGW3-2 and qGL3-2, were detected in the same chromosomal interval at the same position. These findings will benefit breeding design for development of high yielding variety in rice.

Rice stripe virus (RSV) is one of the major constraints in rice production which is transmitted by the small brown plant hopper, Laodelphax striatellus. Identifying new resistance genes from diverse sources is important for rice breeding programs to enhance the resistance level and/or to overcome the breakdown of resistance genes. This study was conducted to identify novel sources of resistance against RSV. We used five RSV resistant varieties that do not harbor Stv-bⁱ. The presence of known genes for RSV resistance was identified using the InDel7 marker for Stv-bⁱ, two Indel (Sid primer set) markers for Stv-b, and DNA sequence analysis for OsSOT1. We revealed that two varieties, 02428 (IT236925) and Tung Ting Wan Hien 1, are novel RSV resistance sources.

Rice tungro disease is a serious threat to rice production in South and Southeast Asian countries. Rice production in these countries has been intensified, often through continuous cultivation of rice. We conducted a screen of the resistance to tungro virus disease in Korean japonica rice. Dongjin, Hwaseong, and Sangju were varieties resistant to Rice tungro spherical virus (RTSV) but susceptible to Rice tungro bacilliform virus (RTBV). RTSV-resistant variety Sangju was crossed with RTSV-susceptible variety Unkwang to conduct a genetic analysis for RTSV resistance originating from Sangju. Evaluation of 201 F2 plants from the cross between Unkwang and Sangju showed that there were 85 plants showing resistance, and that 116 plants were susceptible, indicating a ratio fitting a 7:9 ratio ratio (χ² = 0.54; p = 0.46). Thus, the resistance to RTSV in Sangju might be controlled by two recessive genes. This result indicates that Sangju might serve as a useful genetic source for diversification of RTSV resistance and stabilization of resistance through gene pyramiding.

This study was conducted to identify DNA markers related to resistance to herbicide containing mesotrione in Tongil type rice. Two Tongil type elite lines; Milyang154 and Suweon382, showed resistance to mesotrione, whereas the others were susceptible at 20 days after mesotrione application, and severe growth inhibition was observed in the remaining 13 lines. As a result of analysis of mesotrione resistance using 190 F₂ populations derived from a cross of Hanareum2 (susceptible) and Milyang154 (resistant), the mesotrione resistance locus was shown to be a single dominant gene with a 3:1 segregation ratio (X²=1.19, P=0.31). To identify a DNA marker closely linked to the mesotrione resistance gene, bulked segregant analysis (BSA) was adopted. The DNA marker RM3501 was identified on chromosome 2 with a recombinant value of 0.53 to the mesotrione resistance gene. Mst1(t) was located between SSR (simple sequence repeat) markers RM3501 and RM324 with a physical map distance of 10.2 Mb–11.4 Mb on chromosome 2. The band pattern of agarose gel electrophoresis of the SSR marker RM3501 showed the same segregation pattern with respect to mesotrione treatment in 20 Tongil type varieties and a BC₂F₂ segregation population derived from a cross between Unkwang (resistant) and Hanareum2 (susceptible). Thus, the RM3501 DNA marker could be used in breeding programs for Marker Assisted Selection in mesotrione resistant rice breeding.

A new soybean variety, ‘Joongmo 3009’ (Milyang 222) was developed at the National Institute of Crop Science (NICS) in 2012. ‘Joongmo 3009’ was released by pedigree selection from the cross between ‘Cheongja 2(Milyang 121)’ and ‘Daemangkong’.

It has determinate growth habit, white flower, brown pubescence, brown pod color, green seed coat, green cotyledon, spherical seed shape, oval leaf shape and large seed size (29.3 grams per 100 seeds). It was late 16 days in maturing date than the check cultivar ‘Cheongjakong’. The average yield of ‘Joongmo 3009’ was 2.91 ton per hectare, which was higher 36 percentage than the check variety, in the regional yield trials carried out in three adaptable locations of Korea from 2010 to 2012. The number of breeder’s right is ‘5474’

A soybean cultivar for sprout, ‘Joyang 1’ was developed at the National Institute of Crop Science (NICS) in 2010. ‘Joyang 1’ (Iksan67) was released by pedigree selection from the cross between high yielding ‘Pungsannamulkong’ and ‘Suwon187’ tolerant to lodging and disease. It has purple flower, lanceolate leaf, grey pubescence and small yellow seed. Weight of hundred seed is 11.6gram. Maturing date of ‘Joyang 1’ is ten days earlier than check cultivar, ‘Pungsannamulkong’. ‘Joyang 1’ is resistant to bacterial pustule and shattering. It have similar tolerance to root rot and seed spot to check cultivar. It shows high germination ratio, less abnormal germination and hard seed. Sprout yield also 11 percent higher than check cultivar. The average seed yield of ‘Joyang 1’ was 3.03 ton per hectare in the regional yield trials (RYT) carried out for three years from 2008 to 2010 which was 3 percent higher than the check cultivar. The number of breeder’s right is ‘4900’.