AbstractExtensive research has been conducted in wheat to improve genetic resistance to rust, a major disease that deteriorates wheat yield and quality worldwide. Leaf rust caused by Puccinia triticina is the most prevalent among the three major wheat rust diseases (leaf, stripe, and stem rust) globally and is adapted to a wide range of climates. Approximately 80 genes for leaf rust resistance have been reported, and six (Lr1, Lr10, Lr21, Lr22a, Lr34, and Lr67) have been cloned. Among these cloned genes, Lr34/Yr18/Sr57/Pm38 and Lr67/Yr46/Sr55/Pm46 are of special interest for breeding programs, as they provide pleiotropic resistance to stripe rust, stem rust, and powdery mildew as well as leaf rust. In Korea, knowledge on wheat breeding and genetics for rust resistance is insufficient, as agronomic measures have mainly been used to avoid rust. Therefore, an extensive research program to address the increasing threat of rust epidemics due to climate change is urgently required. Major Korean wheat cultivars, breeding lines, and landraces should be screened for leaf rust resistance. Diverse germplasms also need be introduced through international collaborations to broaden the genetic background for resistance. It is equally important to characterize the distribution of different leaf rust races in Korea and respond to changes in pathogen populations by using effective resistance genes in breeding programs. Research on molecular genetics and genomics needs to be furthered to identify new leaf rust resistance genes and develop efficient molecular markers.

AbstractStem rust is a major wheat disease caused by the fungus Puccinia graminis f. sp. tritici (Pgt). Occurring mainly in warm and humid climates, stem rust has generally been considered less prevalent than leaf rust (P. triticina) and stripe rust (P. striiformis f. sp. tritici). However, a highly virulent stem rust race, Ug99, appeared in Uganda in 1998 and has devastated wheat production throughout Africa and the Middle East. As damage caused by the Ug99 lineage and other newly diverging stem rust races continues to increase, extensive research on wheat breeding and genetics to enhance stem rust resistance has been conducted internationally. Among the 60 stem rust resistance genes reported thus far, 11 (Sr13, Sr21, Sr22, Sr33, Sr35, Sr45, Sr46, Sr50, Sr55, Sr57, and Sr60) have been cloned. New resistance sources have been sought by screening diverse wheat germplasms through international collaborations. Such efforts are urgently required in Korea to address the increasing threat of stem rust epidemics. Furthermore, major Pgt races in the Korean peninsula need to be pathotyped. This information can be used to screen major wheat cultivars, breeding lines, and landraces to identify effective resistance sources. Previously reported stem rust resistance genes should also be introduced and pyramided into the genetic background of Korean wheat breeding populations via available molecular markers. Finally, research capacity in molecular genetics and genomics needs to be strengthened to enable the identification of new stem rust resistance genes and the development of precise molecular markers.

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.

AbstractThe SHORT VEGETATIVE PHASE (SVP) gene encodes a MADS-box gene family of transcription factors that repress floral transition. To explore the function of the Brassica rapa SVP (BrSVP) gene during the flowering time of this species, a construct containing BrSVP under the control of the cauliflower mosaic virus 35S promoter was introduced into B. rapa via Agrobacterium-mediated transformation. The resulting transgenic plants showed delayed flowering time, and RT-PCR analyses further revealed that BrSVP repressed the expression of the floral integrator genes AGL20, AGL24, and FT during vernalization. Our data indicated that BrSVP acts as a negative regulator in the flowering time of B. rapa and that it may therefore be a useful genetic source for crop improvement with respect to flowering time regulation.

AbstractIn 2014, a mung bean cultivar, Vigna radiata (L.) R. Wilczek ‘Dado’, was derived from a hybrid between ‘Jeonnam14’ and ‘IT208777’ developed in 2001 at the Jeollanamdo Agricultural Research and Extension Services, South Korea. ‘Dado’ has an erect growth habit, lobed leaflets, green hypocotyls, light yellow corolla, and dull green seed surface. The number of pods per plant was 23.3, 1.5 more than that of the control cultivar ‘Owool’, and the 1000-seed weight was 43 g, 6 g lighter than that of the control. ‘Dado’ and ‘Owool’ exhibited similar field resistance to mung bean mottle virus, cercospora leaf spot, powdery mildew, and lodging. ‘Dado’ had a sprout yield ratio of 824%, 132% higher than that of ‘Owool’, and its hard seed rate was 1.2%, 3.1% lower than that of the control. The average seed yield of ‘Dado’ was 1.9 ton/ha, which was 23% greater than that of ‘Owool’ (Registration No. 5874).

AbstractIn 2014, a new high-quality, pollination-constant, non-astringent persimmon (Diospyros kaki L. Thunb.) cultivar, ‘Wonmi’, a breeding of ‘Fuyu’ and ‘Taishu’ from 2005, was developed. ‘Wonmi’ fruit were harvested on October 8 in Yeongam, South Korea. The fruit are medium-sized (220 g on average), with a high amount of soluble solids (15.1 °Bx). The juicy flesh has a pleasant taste and crispy texture. The fruit shape is round oblate, and the skin color is orange with a graceful appearance. Physiological disorders, such as stylar-end or fine skin cracking, rarely occur in this cultivar (Registration No. 7724).

AbstractIn 2016, ‘Jinyulmi’ was developed as a sweetpotato variety with good palatability and high marketable storage root yield. It was derived from a cross between ‘Sinchunmi’ and ‘Jeonmi’. ‘Sinchunmi’ is small, with an average storage root weight of 141 g and an average number of marketable storage roots of 3.4. ‘Jeonmi’ has a high storage root yield of 26.2 MT/ha and intermediate steamed storage root texture. The storage roots of ‘Jinyulmi’ are elliptical and have red skin and yellow flesh. ‘Jinyulmi’ is resistant to Fusarium wilt and moderately resistant to root-knot nematode. The steamed storage root texture of ‘Jinyulmi’ is intermediate and more tender than that of check variety ‘Yulmi’. The sweetness of ‘Jinyulmi’ steamed storage roots was 13.1, which was 12.9% higher than that of ‘Yulmi’. ‘Jinyulmi’ steamed storage roots are also more palatable than those of ‘Yulmi’. The marketable storage roots yield of ‘Jinyulmi’ was 24.2 MT/ha in the early season culture, which was 26.0% higher than that of ‘Yulmi’. Its average marketable storage root weight was 137 g in the normal season culture, which was lower than that of ‘Yulmi’, but the number of marketable storage roots per plant was 3.6, which was higher than that of ‘Yulmi’. The marketable storage root yield of ‘Jinyulmi’ was 28.6 MT/ha in the normal season culture, which was 19.7% higher than that of ‘Yulmi’. ‘Jinyulmi’ is, therefore, suitable for both early and normal season cultures (Registration No. 7053).

Abstract‘Daegwang’ was developed in a potato breeding program at the Highland Agriculture Research Institute, National Institute of Crop Science, Rural Development Administration, South Korea. It was selected from the hybrid ‘Haryeong’בP03404-1’ from 2007. In 2011-2012, the major agronomic characteristics of this variety were evaluated in Gangneung for spring cultivation and Pyeongchang for summer cultivation as clone number ‘P07917-4’. ‘P07917-4’ was renamed as ‘Daegwan 1-127’, and regional yield trials for this clone were conducted in Cheongju, Naju, Gangneung, and Pyeongchang in 2013-2015. This cultivar was registered as ‘Daegwang’, based on its key agronomic characteristics, including drought tolerance, late blight resistant, and high yield. It has medium maturity and a semi-erect growth habit. ‘Daegwang’ has a round to short oval tuber shape, shallow eye-depth, yellow skin color, and white flesh color. Its leaf color is green, and its white flowers bloom abundantly. This cultivar is resistant to potato late blight but susceptible to potato common scab. The incidences of hollow heart and internal brown spot were low. However, the frequency of tuber cracking was high, at about 6.0% in summer cultivation in Pyeongchang. In the regional yield trials, ‘Daegwang’ had an average tuber yield of 34.1 ton/ha, which was 6.2% higher than that of ‘Sumi’, and its dry matter content was 16.8%. Boiled ‘Daegwang’ tubers have a viscous-floury texture and a pleasant taste. ‘Daegwang’ is expected to be produced as a table potato. (Registration No. 7664).