충청남도농업기술원 화훼연구소에서 2021년에 개발된 ‘Pinky Lang’은 분홍색 홑꽃 타입의 스프레이 국화 신품종 이다. ‘Pinky Lang’은 2016년 10월에 육종 하우스 내에서 2016년에 순백색의 진한 녹심이 매력적인 품종으로써 선발 된 백색 홑꽃의 ‘Bodre’ 품종을 방임 수분하여 48개의 종자 를 채취했다. 채취한 종자를 2017년 파종한 뒤 우수개체로 선발되어 2017년부터 2020년까지 4년간 촉성, 억제, 자연개 화 작형별 주년생산성 검정을 수행하여 선발된 우수계통을 ‘SP17-425-01’이라 계통명을 부여하였다. 2020년 최종적으 로 우수한 계통으로써 평가 및 심의를 받은 뒤 ‘충남SP-68 호’로 명명하였고, 당해 년도 12월 직무육성 신품종 선정위원 회를 통과하여 품종명은 ‘Pinky Lang’으로 하였다. ‘Pinky Lang’은 고온기에 화색이 변하지 않고 녹심이 매우 진하며 줄 기가 튼튼한 품종이다. 여름철 흰녹병에도 강하여 고온기 수출 품종으로 적합하다고 판단되었다. ‘Pinky Lang’은 연중 3 작기 재배테스트에서 단일처리 후 개화소요일수는 자연개화 작형 52일, 촉성작형 49일, 억제작형 50일이었고, ‘Yes Luna’ 는 각각 51일, 52일, 52일로 전반적으로 개화소요일수가 짧 았다. ‘Pinky Lang’의 절화장과 줄기굵기는 각각 104.5cm, 4.71mm으로 ‘Yes Luna’가 109.5cm, 4.25mm인 것에 비 해 5cm정도 짧았고 줄기굵기는 0.46mm 더 굵었다. ‘Pinky Lang’의 꽃 크기는 5.6cm이고 ‘Yes Luna’는 6.8cm로 1.2cm 작았다. ‘Pinky Lang’의 한 줄기에 달리는 꽃의 수와 한 송이 당 꽃잎수는 각각 27.7개, 30.9매였고, ‘Yes Luna’ 는 각각 18.0개, 37.0매인 것으로 착화수는 9.7개 많았고 꽃 잎수는 6.1매 적었다. 여름철 재배테스트를 통해 확인해본 결 과 흰녹병 저항성이 높은 경향을 확인하지만, 1~10% 정도의 병반을 보여 완전저항성을 가지진 못하는 것으로 사료된다. 자연개화 작형에서 절화수명의 경우는 24.5일로 ‘Yes Luna’ 에 비해 2.1일 길었다. ‘Pinky Lang’은 과습한 경우 줄기가 연약해질 수 있기 때문에 생장억제제인 Daminozide를 처리 하여 줄기를 강건하게 하고 절화 품질의 균일도를 높여 고온 기 재배에 안정적인 생산이 가능하여 수출할 수 있다.

화훼류 중 절화류의 화색과 향기 특성을 조절하는 것은 주 요한 육종 목표로써 인지되어 왔다. 최근 다양한 소비자 계층이 증가하면서 파란색 장미, 카네이션 등과 같은 특이화색이 라든지, 독특한 향기를 갖고 있거나 그 강도를 조절하고자 하 는 연구방향 또한 다양해졌다. 그러나 이것은 일반적으로 수 행하고 있는 교배방식으로는 특정 목표형질을 가진 품종을 개 발하기란 쉽지가 않다. 그래서 화색과 향기와 관련한 형질을 조절할 수 있는 유전공학적인 방법뿐만 아니라 다방면의 연구 가 진행되어 왔다. 이는 화색과 향기의 관련 식물 대사산물을 생산 하는 것을 비롯하여 유전공학적인 방법으로 조절하는 방 식 등 여러 가지 방법이 있다. 많은 예 중에 화훼작물의 화색 과 향기를 조절한 성공한 사례를 바탕으로 어떻게 하면 우리 가 원하는 방향에 가까운 화색과 향기의 특정 형질을 만들어 낼 수 있을지에 대해 정리해보고자 하였고, 이러한 것들은 잘 응용하여 추후 좀 더 많은 화색과 향기를 만들어낼 수 있는 전략을 수립하는 데 도움이 되고자 한다.

본 연구는 감마선 조사 및 배양방법을 이용하여 유 용한 변이체를 선발하고, 그 특성을 관찰하기 위해 수 행되었다. 기내 신초수의 증식은 MS 배지 내에 NAA 0.2mg·L-1에 BA의 농도가 1.0mg·L-1로 증가할수록 양호한 반면 신초의 길이와 뿌리형성율은 감소되었다. 계대배양을 3회 수행한 후 온실에서 순화 및 삽목하였다. 감마선으로 조사된 총 370 개체들은 감마선의 조 사선량에 관계없이 토양이식 후 생존율이 97% 이상이 었다. 조사된 개체들 중 변이의 빈도는 감마선의 선량 이 증가할수록 높아졌다. 50Gy 조사구에서는 화색과 화형의 변이가 각각 28.2와 15.4%로 확인되었다. 화 색과 화형은 다양한 변화를 나타냈으며 줄기색 또한 변화되었다. 예를 들면 흰색에 옅은 자주색의 관상화는 흰색, 적자색, 노랑색 또는 연분홍색 등으로, 흰색이었 던 설상화는 연한 자주색이나 적자색으로 바뀌었다. 설 상화의 길이와 폭 및 화경의 크기가 달라진 개체 및 줄기에서 안토시아닌 색소가 제거된 개체도 관찰되었 다. 본 연구결과 국화 ‘Argus’에서 기내 배양체에 30- 50Gy의 감마선 조사에 의해 화색, 화형 및 줄기색의 다양한 돌연변이체를 선발할 수 있었다.

Compared to wide ranges of genetic variation of natural populations, very limited Miscanthus cultivar has been released. This study was the first report on the development of Miscanthus cultivar by means of radiation breeding. Seeds of M. sinensis were initially exposed to gamma rays of 250 Gy for 24 h, generated from a 60Co gamma-irradiator. The irradiated seeds were sown and then the highly tiller-producing mutants were selected for this study. Biomass-related parameters including tiller number, plant height, stem diameter, and leaf number were measured. Ploidy level and internal transcribed spacer (ITS) were investigated to characterize the mutants compared to wild type (WT) Miscanthus. Plant height and tiller number were negatively related, where multi-tillering mutants were relatively short after 4 month growth. However stem diameter and leaf number were greater in mutants. All the materials used in this study were diploid, implying that the mutants with greater tiller numbers and stem diameter were not likely related to polyploidization. Based on the sequence of ITS regions, the mutants demonstrated base changes from the gamma irradiation where G+C content (%) was decreased in the ITS1, but increased in ITS2 when compared to WT sequence. ITS2 region was more variable than in ITS1 in the mutants, which collectively allows identification of the mutants from WT. Those mutants having enhanced tillers and allelic variations might be used as breeding materials for enhanced biomass-producing Miscanthus cultivars.

Miscanthus is one of the important crops for bioenergy feedstock. Applicable molecular makers would be useful for development of valuable cultivar with enhanced biomass. Microsatellites as a co-dominant are widely useful for many applications in plant genetics and breeding such as genetic diversity analysis, cultivar identification, and marker-assisted selection. In order to develop novel EST-SSR markers for genetic improvement, we obtained the EST sequence data from the constructed cDNA libraries using a leaf and rhizome organs in the M.sinensis and M.sacchariflorus. SSR motifs were identified by SSR search-module program SciRoKo software. The number of SSR motifs was 1,724 in M.sinensis (leaf: 948, rhizome: 776) and 1,158 in M.sacchariflorus (leaf: 549, rhizome: 609). The most common repeat was tri-nucleotide followed by tetra-, di-, penta-nucleotide. CCG and AGC motifs were detected the most abundant repeat type in tri-nucleotide. We used an ORF Predictor program to screen the SSR location in the genome. The majority of the motifs were located in the ORF regions than the untranslated regions (UTRs). Especially, the tri-nucleotide was localized in the ORF regions, whereas di- and tetra-nucleotide were frequent in UTR regions. Based on SSR-containing sequence of the M.sinensis (leaf), 228 primer pairs were designed using Primer3 program. Randomly selected 20 primer pair was firstly screened using genomic DNA for their effectiveness to amplify SSR fragments of the expected size and to detect allele polymorphism. Fourteen out of total twenty primer pairs (70%) were successfully amplified. The remaining SSRs will be further screened and reported. When confirmed, those SSRs will be used for studying genetic diversity of the collected Miscanthus germplasm.

Reliable and precise techniques for targeting modification of plant genomes have been explored in plant breeding communities. Initiated in the animal genome first, now the genome editing tool using a nuclease has been reported in some plant species including Arabidopsis, Maize, Tobacco, and other model systems. When the artificial nuclease is introduced into a plant cell and breaks the genomic sites randomly, endogenously operating DNA-repair mechanisms including non-homologous end joining(NHEJ) or homologous recombination(HR) are anticipated, leading to insertion of foreign DNA or deletion of the target locus, which collectively allows changes in plant traits of interest. Traditionally custom designed for induction of double-strand DNA break(DSB) at a predetermined locus was based on zinc-finger nuclease which contains nonspecific cleavage domains with target specificities of DNA binding zinc finger domains(three to four). The binding domains containing more than 20 DNA bases with high affinity to the target gene enable recognition of the locus efficiently. From this project, we focus on a petunia chalcone synthase(CHS) as a model system. The engineered nuclease will target the CHS gene, which is expected to be modified either constitutely or transiently. The derived transformed plants will be genetically or phenotypicly screened, along with molecular confirmation analysis by using various tools. We eventually extend the tools to various crop species and target genes, which makes the brand-new breeding technique more reliable and robust.

We bred a new green-kerneled glutinous rice variety that can be cultivated in the whole area of Korea, because only one native green-kerneled glutinous rice cultivar, “aengdongchalbyeo” has been cultivated in the southern coastal area due to its late heading. The seeds of “aengdongchalbyeo”were irradiated with 200 Gy of gamma ray in 1995. A promising mutant variety, “ogwonchalbyeo”(“onnong 17” was selected through line selection and regional yield trials. In particular, the new variety revealed at the earlier mid of August compared to that of “aengdongchalbyeo” the early of September, and it was considerably tolerant to a field lodging due to its shortened culm length. Also, “ogwonchalbyeo”had a higher ripened grain ratio and 1,000 grain weight compared to the original variety. The brown grain yield of the new variety was about 5.40 MT/ha, which was 11.3% higher than that of the original variety, in the regional yield trials at 3 different fields during 2000∼2001. The brown and milled grains of the new rice variety contained 20 to 65% higher amount of total amino acids, respectively than that of the original and two checks. For chlorophyll -a, -b and total chlorophyll, the new variety showed nearly two-fold higher than the checks, and for the carotenoid, it had 5.3 –7.6 times higher amount. These results showed that the new variety can be cultivated as a special green-kerneled glutinous rice with high functional compounds.

Encouraging progress in the mutation breeding has been achieved since a mutation induction has become increasingly important for a cultivar development for complex reproductive or propagating modes, the creation of new genetic resources, especially for crops with a narrow genetic base, and the use of mutants for a genomics study. In Korea, more than 35 cultivars have been released by using the mutation breeding method since the mid-1960s, and the released cultivars were mostly developed (76%) by exposing to radiations (gamma and/or X-ray). Most of the released mutant cultivars (74%) in Korea were food and oil seed crops, especially for improving agronomic traits such as yield, lodging tolerance, maturity, or functional compounds. Currently a high yield potential of cultivated crop cultivars is relatively less popular than before, but the expectation of value-added crops, from the farmer’s side, is in high demand. Accordingly, the mutation breeding program in Korea has assigned more resources to other crop species, including some flowering and ornamental plants. These flowering and ornamental plants are ideal systems for a mutation breeding because their favored traits such as flower color or shape or plant architecture can be visually monitored after a mutagenic treatment. Additionally, these plant species are genetically heterozygous and often propagated vegetatively, which allows for an isolation and selection of mutants within M1 generation. In Korea, a program for the development of potential cultivars of flowering and ornamental crops was launched with financial support from the Biogreen 21 project in RDA. Thisintegrated program which will be conducted by a diverse array of experts will focus on major flowering and ornamental crops in Korea such as rose, chrysanthemum, lily, carnation, orchids, and clover. The potential outcomes from the program will be new highly valued-added cultivars which will provide greater money gains to Korean farmers and lots of valued mutants used for a gene isolation of interest and reverse genetics or functional genomics. Appropriate strategies should be implemented to complete its goals successfully, which includes a)induction of a wide mutant spectrum, b)applications of new irradiation techniques, c)unraveling the complex genetic phenomena controlling mutant traits, and d)development of a mass production and an intensive export system for the developed cultivars.