Bakanae disease, also known as the foolish seedling disease, caused by Gibberella fujikuroi, is a serious issue in Korea. Since 2007, there has been a rapid increase in the occurrence of bakanae disease; this has caused severe yield loss to rice farmers every year. The most reliable and economical solution for managing bakanae disease is to cultivate resistant varieties; however, there are only a few rice varieties in Korea that can withstand this disease. Therefore, this study aimed to evaluate the resistance of 61 major rice varieties which account for 89% of the total rice cultivation area. Only six varieties showed intermediate or higher resistance to bakanae disease; this included Anpyeong and Samkwang. The genetic inconsistency between the bioassay results and the allele types of 12 molecular markers (associated with four QTLs) ranged from 4.7% to 48.7%. Therefore, more accurate markers, such as gene-based markers, are essential for monitoring general breeding programs or gene pyramiding.

Mutation breeding through irradiation has been applied to several varieties and genetic resources since the discovery of the use of X-rays for inducing mutations in plants by Stadler in 1928. A heavy ion beam with high linear energy transfer (LET) shows a higher relative biological effectiveness (RBE), and it is more effective in inducing plant mutations than low LET radiations, such as X-rays, gamma rays, and electrons. Since early 1990s, several plant breeding programs in Japan have used heavy ion beams from accelerators. These beams impart a high energy effect on a local target; therefore, they induce a higher number of single and double strand DNA breaks. In addition, they induce a large number of DNA deletions than low LET radiations. Therefore, a heavy ion beam is superior to low LET radiations in terms of induction rate and the mutation spectrum. In Korea, a heavy ion accelerator that can be used for breeding is under construction. However, a large-capacity proton accelerator (KOMAC: Korea Multi-purpose Accelerator Complex) was built recently, and it is a pioneer step in breeding research worldwide. This review summarizes the basic characteristics, successful research achievements, and the prospect of application of high LET accelerator beams in plant mutation breeding.

The grain size and shape have a significant impact on the grain quality and yield of rice. Additionally, due to the globalization of the rice market, there is a demand for rice varieties of various sizes. In this study, we analyzed quantitative trait loci (QTL) associated with grain length (GL), grain width (GW), grain thickness (GT) and ratio of length-to-width (RLW) using 149 F₂ plants obtained from a cross between Hopum and Basmati 370. To construct a linkage map, we utilized 89 Fluidigm SNP markers, which covered a span of 1,116 cM of F₂ population. Nine QTLs associated with four traits were identified on chromosomes 2, 3, 5, and 7. One major QTL on chromosome 3 accounted for 43.2% of the phenotypic variation in GL. Additionally, QTLs named qGW2 and qGW5 on chromosomes 2 and 5 were detected for GW, explaining 10.4% and 18.6% of the phenotypic variation, respectively. Three QTLs for GT were found on chromosomes 2, 5, and 7, explaining 9.9%, 12.9%, and 9.9% of phenotypic variation, respectively. These QTLs offer potential applications in breeding programs using Basmati 370 to develop long and slender grain japonica varieties.

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.

‘Halla Green 11’ is a Zoysia matrella cultivar showing short height and extended greening period lines at low temperatures of winter than general warm season zoysiagrasses. ‘Halla Green 11’ Z. matrella was collected from the seaside cliffs in Geogeum Island, Jeollanam-do. The turfgrass was transplanted to the genetic resources greenhouse and propagated in the test field. Among the zoysiagrasses cultivated in the greenhouse and test field, Z. matrella, which had a short height and showed extended greening period lines during the low temperatures of winter, was finally selected and named ‘Halla Green 11’ and was registered in June 2022. The main external morphological characteristics of the ‘Halla Green 11’ variety were analyzed using the test guideline (TG) of the Korea forest service, which is described as follows: Since the turfgrass has a ‘Leaf sheath’ of a short length, the mowing height can be lowered, rendering mowing easy. Furthermore, the ‘Plant height’ and the length of the ‘Leaf blade’ are short. The ‘Leaf blade width’ is narrow, and trichomes on the leaf surface are not present. Hence, ‘Halla Green 11’ is morphologically classified as Z. matrella. The leaf angle is very wide. The colors are green for ‘Leaf blade’, light green for ‘Leaf sheath’, and light purple for ‘Stolon’. Particularly, during the low-temperature period of winter, ‘Halla Green 11’ showed approximately 25.2, 10.6, and 8.1-fold high levels of leaf chlorophyll than the control cultivar ‘Yaji’, control Zm-6, and Zm-19, respectively. Owing to the short height of the plant and extended greening period phenotype, ‘Halla Green 11’ is expected to be highly preferred by consumers (Registration No. 274).

‘Halla Green 12’ cultivar is characterized by Zoysia matrella×Zoysia japonica. It was selected as a warm season zoysiagrass with an extended greening period phenotype at low temperatures and a short plant height. Inflorescences of Z. matrella lines were collected near the boundary between wild Z. matrella lines and wild Z. japonica lines in Ora-dong, Jeju-do. Seeds were collected from the inflorescence and sown to obtain hybrid lines of Z. matrella and Z. japonica, ranging from the Z. japonica line to the Z. matrella line. Among the collected zoysiagrasses, a hybrid line of Z. matrella and Z. japonica, which showed a short height and characteristics of extended greening periods in greenhouses and test fields during winter, was finally selected and named ‘Halla Green 12’. Subsequently, it was registered in June 2022 (Registration No. 277). The test guideline (TG) of the Korea Forest Service was used to analyze the main external morphological characteristics of the ‘Halla Green 12’ cultivar, described as follows. ‘Halla Green 12’ cultivar has a short ‘Plant height’ (6.14±0.37 cm), ‘Leaf blade’ (4.15±0.36 cm), and ‘Leaf sheath’ (1.39±0.08 cm). The ‘Leaf angle’ is very wide at 61.5°. Since the ‘Leaf blade’ of ‘Halla Green 12’ has no ‘Trichomes,’ and the ‘Leaf blade width’ is as narrow as 1.69±0.06 mm, it is morphologically classified as a hybrid line of Z. matrella and Z. japonica, which is close to Z. matrella. In particular, during the winter period, ‘Halla Green 12’, which was grown in the test field, showed an extended greening period with green and reddish-purple leaf colors. The chlorophyll levels of the leaves of ‘Halla Green 12’ cultivar were 2580.2±175.6 nmol/mL/g, which were approximately 13.4-fold higher than those of the control variety ‘Yaji’ and 5.6-fold higher than those of the control Zm-6. ‘Halla Green 12’ showed the characteristics of extended greening period. Since the ‘Halla Green 12’ cultivar is characterized as Z. matrella×Z. japonica, which is close to Z. matrella with short ‘Plant growth’ and characteristics of extended greening periods, it is expected to be useful for reducing management costs, such as those attributed to mowing and industrializing lawn greening (Registration No. 277).

A new covered barley cultivar ‘Hangang’ with resistance to barley yellow mosaic virus (BaYMV) and tolerance to cold was developed by crossing ‘Samkwangchal/Radiant’ at the National Institute of Crop Science, RDA in 2018. The regional yield trials were conducted for ‘Hangang’ as a breeding line ‘Jeonju498’ in five different regions from 2016 to 2018. The average heading date of ‘Hangang’ was April 22, which was one day earlier than that of ‘Olbori’. The maturing date of ‘Hangang’ was May 30, which was similar to that of ‘Olbori’. The culm length was 81 cm, which was shorter than that of ‘Olbori’, showing tolerance to lodging stress. ‘Hangang’ showed the spike length of 4.6 cm with 669 spikes per m², 54 grains per spike, and a weight of 33.5 g for 1,000 grains. Compared with ‘Olbori’, ‘Hangang’ showed stronger withering in winter (winter hardiness) and resistance to BaYMV. Among quality characteristics, ‘Hangang’ showed similar levels as those of ‘Olbori’ with respect to protein, β-glucan and amylose (10.7%, 4.6%, and 18.8%, respectively). However, ‘Hangang’ showed higher polyphenol content (1.69 mg/g) than the check cultivar. The yield of ‘Hangang’ in the regional yield trial was 611 kg/10a in upland, 502 kg/10a in paddy field, and an overall average of 567 kg/10a, which was 15%, 16% and 16% higher than that of the check cultivar, respectively. Therefore, ‘Hangang’ will be suitable cultivar when sowed in cold regions (Registration No. 8773).

‘Gowoo’, a mid-late flowering, high yielding rice (Oryza sativa L.) cultivar with glabrous leaf and hull and resistant to multiple diseases and insects, was developed for forage use. It was developed for use as a whole crop silage obtained from a cross between ‘Kusahonami’ with high biomass, smooth leaf and hull, lodging resistance and Japonica high yielding line ‘Iksan514,’ which showed resistance to bacterial blight (BB) (race K1, K2, K3) and rice stripe virus (RSV). In the central plain region of Suwon, ‘Gowoo’ cultivar exhibited a growth period of approximately 120 days from seeding to heading, 111 cm culm length, 22 cm panicle length, 12 panicles per hill, 140 spikelets per panicle, and 1,000-grain weight of 23.4 g as brown rice. This hairless forage rice variety was weak in response to cold stresses, similar to ‘Nokyang’. However, it was resistant to lodging in the field and showed a strong response to viviparous germination. In addition, ‘Gowoo’ was resistant to leaf and neck blast, BB, RSV, and small brown planthopper. Its average dry matter yield for three years reached 18.2 MT/ha, which was 21% higher than that of ‘Nokyang’. This glabrous cultivar had 5.3% crude protein and 68.2% total digestible nutrients, a little low compared to ‘Nokyang’. In Korea peninsular, ‘Gowoo’ grows well in central and southern plain and is good to harvest between 15 to 30 days after heading to improve its feeding value and digestion rate of livestock (Grant No. 8681).

Potato late blight caused by the fungus Phytophthora infestans is one of the most important diseases worldwide. Developing potatoes with resistance to late blight through breeding programs is a key research interest in Korea. ‘Mangang’ was bred for late blight resistance through a breeding program at the Highland Agriculture Research Institute of National Institute of Crop Science. The population derived from the cross between ‘Atlantic’ as the female parent, which has excellent chipping quality and ‘CIP393371.159’ as the male parent, a late blight-resistant clone introduced from International Potato Center (CIP), was selected. In ‘Mangang’, the plant maturity occurs late and the growth habit is of the erect type. The tuber shape is round and eye-depth is medium. The skin color of ‘Mangang’ is light yellow; however, there are pink spots around the eyes of the tuber, and the flesh color is white. Leaf color is green and flower color is light-purple. ‘Mangang’ exhibits resistance to early blight (Alternaria solani) and leaf roll virus (PLRV). In addition, it has moderate resistance to common scab (Streptomyces scabies). The response to late blight was evaluated in a non-agrochemical treated field for five years between 2012 and 2016; ‘Mangang’ exhibited resistance to late blight. The mean AUDPC (Area Under Disease Progress Curve) values of ‘Mangang’ and ‘Atlantic’ were 165.5 and 795.8, respectively. Total tuber yield from the non-agrochemical application trial at three regions during the five years was 40.3 ton/ha; this was 40.4% higher than that from ‘Atlantic’. The dry matter content of ‘Mangang’ was 21.3%, which was slightly higher than that of ‘Atlantic’. The chip color was 66.5, and the chip processing quality of ‘Mangang’ was at a level similar to that of ‘Atlantic’ (Registration No. 9312).

‘Baeksoojeongchal’, a new naked waxy barley cultivar was developed from a cross between ‘Jinmichapssal’ and ‘Radiant’ at the National Institute of Crop Science, RDA in 2019. ‘Baeksoojeongchal’ is a white, waxy naked barley cultivar with a low browning reaction owing to the low levels of proanthocyanidin. Regional yield trials were conducted for ‘Baeksoojeongchal’ as the breeding line, ‘Jeonju135’ at four different regions between 2017 and 2019. The average heading date of ‘Baeksoojeongchal’ in the paddy field was April 20, which was a day later than that of ‘Saechal’. Maturing date of ‘Baeksoojeongchal’ in the paddy field was May 26, which was 2 days later than that of ‘Saechal’. It has a short culm length of 75 cm and a short spike length of 4.3 cm, with 48 grains per spike and a 1,000-grain weight of 29.5 g. Compared to ‘Saechal’, ‘Baeksoojeongchal’ shows weaker winter withering and has better tolerance to lodging. The incidence of BaYMV (Barley yellow mosaic virus) in ‘Baeksoojeongchal’ was similar to that in ‘Saechal’; in addition, it was susceptible to powdery mildew. The grain quality characteristics of ‘Baeksoojeongchal’ indicated a similar protein content (9.6%) and a lower proanthocyanidin content (0.011%) and whiteness (42.0) compared to that in ‘Saechal’. The average yield was 505 kg/10a in the paddy field, which was 7% higher than that of ‘Saechal’. ‘Baeksoojeongchal’ is the naked waxy barley cultivar with the most whiteness and low proanthocyanidin content; therefore this could contribute to the promotion of barley consumption, by avoiding reduction in consumer preference (Registration No. 9194).