Sesquiterpene lactones (SLs) are a group of over 500 compounds, characteristic of the Asteraceae. They are interesting from the chemical and chemotaxonomic point of view, and show antitumour, anti-leukaemic, anti-cardiovascular disease, reduction of inflammation, and anti-microbial activities. The SLs, free lactucin and lactucopicrin, content in 572 accessions of lettuce (Lactuca sp.) germplasm introduced from 30 countries were quantified using high-performance liquid chromatography. Variation range of free lactucin content exhibited trace ~ 235.3 μg from 1g of dried leaves and average was 41.2 ± 1.2 μg (Avr ± SE), variation range 55.0 ~ 3,041.0 μg and average 526.9 ± 17.5 μg in free lactucopicrin content, and variation range 66.3 ~ 3,188.5 μg and average 568.1 ± 18.1 μg in total free SLs content. Lactucopicrin occupied 92.7% of the total SLs content. Among the varietal types, crisphead type exhibited the highest average total free SLs content, next is leaf lettuce, and butterhead type lettuce exhibited the lowest that of content. German accessions exhibited the lowest average total free SLs content, Korean accessions exhibited the highest, and European origin accessions exhibited lower that of content. Red leaf color accessions having higher SLs content than that of green color. Seven accessions having more than 2,000 μg·g-1 dwt of total free SLs content and five accessions having less than 100 μg·g- 1dwt that of content. These accessions can be used as low SLs content cultivar breeding or high SLs content cultivar breeding sources as well as research materials for medical treatment such as, anti-tumour, anti-leukaemic, and antimicrobial activities, etc.

Soft rot caused by Pectobacterium carotovorum subsp. carotovorum is a destructive disease of the fleshy storage tissues of vegetables and ornamentals that occurs worldwide. This study was carried out to find an effective method for evaluating soft rot disease on a massive scale in greenhouse and to screen resistant accession for the disease with lettuce germplasm. Spray method with 5 mL suspension of 109 colony formation unit per milliliter (CFU/mL) of P. carotovorum subsp. carotovorum per plant at the 6 ~ 7 foliage leaf stage was the most effective to evaluate soft rot disease. We evaluated resistance to soft rot using this method for 812 accessions of lettuce germplasm introduced from 52 countries. As the results, withered rates for each germplasm accession ranged from 0 to 100 percent and among 812 accessions of lettuce germplasm investigated, 21 accessions showed very high resistance. Among the 21 accessions, 11 accessions were from Korea, each 2 accessions were from USA and Israel, and each 1 accession was from Afghanistan, Germany, Hungary, Netherlands, Pakistan, and Uzbekistan. Accessions from Israel, Syria, and Afghanistan showed high resistance level. Among very high resistant 21 accessions, 12 were landraces, 6 were cultivars, and 3 were wild relatives. The 21 accessions were consisted of 12 leaf lettuce, 5 romaine type, 3 wild relatives, and 1 butterhead lettuce. Leaf lettuce accessions showed the highest resistance level while crisphead lettuce accessions had the lowest resistance level among the cultivated lettuce types. Wild relatives had greater resistance than landraces and cultivars. These accessions which resistance to soft rot will be used for soft rot resistance breeding program in lettuce.

중앙아시아에서 수집한 꽃피는 마늘 A. longicuspis의 주아와 주아를 도입해서 생산한 1년생 통구를 각각 노지에 재배하여 우리나라에서 주아재배를 통한 종구(통구)생산과 통구재배를 통한 마늘생산 가능성을 검토하였다. 평균 월동율은 주아재배에서 77.3%, 통구재배에서는 100%로서 우리나라의 대표적인 재래종인 단양마늘이나 의성마늘에 비하여 훨씬 높아서꽃피는 마늘의 주아와 통구를 중부지방에서 재배함에 있어서월동성은 큰 문제가 되지 않을 것으로 사료되었다. 주아재배에서 월동한 모든 개체가 통구 수확이 가능하였고 통구 형성율은 모든 자원이 100%이었다. 통구재배에서 추대율이 100%이었으며, 재래종 대비 화경장이 길고 주아 수가 많았다. 구크기는 대부분이 재래종에 비하여 작았지만 K248215 자원은구중이 40 g으로서 단양마늘과 비슷하였으며 구당 쪽수는 재래종에 비하여 대부분의 자원이 많았고 화기에 꽃과 주아가동시에 존재하였으며 주아를 제거하지 않은 상태에서는 종자가 맺히지 않았다.

This study describes an efficient and stable droplet vitrification following cryopreservation of strawberry shoot tip (Fragaria × ananassa Duch.) accessions ‘Massey’ and ‘MDUS3816’. The shoot tips were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.7M). Precultured explants were osmoprotected with loading solution (LS, C4) containing 17.5% glycerol and 17.5% sucrose for 40 min and exposed to dehydration solution (B1) containing 50% glycerol and 50% sucrose for 40 min at 25oC. Subsequently, the explants were transferred onto droplets containing 2.5 μL PVS3 on sterilized aluminum foils (4 ㎝× 0.5 ㎝) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regrowth rate (%) in both the cultivars was obtained when the shoot tips were precultured with 0.3M sucrose for 30 h + 0.5M sucrose for 16 h at 25oC. The cryopreserved shoots tips exhibited 57.8 % recovery rate by culturing in NH4NO3-free MS medium supplemented with 3% sucrose, 1.0 g/L casein, 1.0㎎/L GA3, and 0.5 ㎎/L BA for 5 weeks and in MS medium supplemented with 0.5 ㎎/L GA3 for 8 weeks. Variation was not observed in both of ploidy analysis and morphological investigation on plantlets of two accessions cryopreserved under variable preculture conditions.

Cryopreservation is one of the ideal and suitable methods for long-term storage of plant germplasm. The plant contaminated with diseases and pathogens are decreased the multiplication rate, survival rate and high quality of plants after cryopreservation. The aim of this work was to improve a micropropagation method for lily in Korea, which is indigenous plant. In the last process of rinsing scales after surface-sterilization, we tried to control the diseases and pathogens lived within the tissue by rinsing in 0.03% sodium hypochlorite (NaClO) instead of sterile distilled water. Bulb scales of Lilium were cultured in vitro on MS medium supplemented with Plant Preservative Mixture (PPM). The results showed that L. tsingtauense accessions were observed ranged from 53.9 to 100% with a mean value of 76.8% and L. hansonii accessions were checked from 84.5 to 85.5% with a mean of 85% survival rate. The newly small bulb formed from bulb-scales was transferred to MS medium. We checked the presence of microorganisms and survival rate after 3 weeks in culture after examination of bacterial incidences. The results indicated that the non-contamination rate were shown ranged from 75.0 to 94.1% with mean value of 83.2% in L. tsingtauense species, and that L. hansonii were observed 85.1 to 91.7% with mean value of 88.4%. This study will provide a valuable basis for establishment of effective axenic cultures for in vitro micropropagation of Korean native lily species.

This study describes an efficient and widely applicable droplet-vitrification following cryopreservation for shoot tips of strawberry (Fragaria × ananassa Duch.) cvs. ‘Wonkyo3114’ and ‘Gurumi40’. The shoot tips were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.5M). Precultured explants were osmoprotected with loading solution (LS, C4) containing 20% glycerol and 20% sucrose for 40 min and exposed to dehydration solution (B5) containing 40% glycerol and 40% sucrose for 40 min at 25℃, Subsequently, the explants were transferred onto droplets containing 2.5 μL PVS3 on sterilized aluminum foils (4 ㎝ × 0.5 ㎝) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regrowth rate (%) in both the cultivars was obtained when the shoot tips were precultured with MS + 0.3M sucrose for 40 h at 25℃. The cryopreserved shoots tips exhibited 55% regrowth rate by culturing in NH4NO3-free MS medium supplemented with 3% sucrose, 1.0 g/L casein, 1.0㎎/L GA3, and 0.5 ㎎/L BA for 5 weeks and in MS medium supplemented with 0.5 ㎎/L GA3 for 8 weeks. This result shows that droplet-vitrification could be employed as a promising method for cryostorage of strawberry germplasm.

This study describes the successful establishment of a cryopreservation protocol for Citrus limon cultivars: ‘Frost Eureka limon’ and ‘Cook Eureka limon’, using a droplet-vitrification method. The shoot tips that were excised from in vitro grown seedlings of the two cultivars were preserved in liquid nitrogen (LN) and successfully regenerated into whole plants. Excised shoot tips were pre-cultured for 1 or 2 days in 0.3 M and 0.5 M sucrose solutions at 25℃ and incubated in a loading solution (LS) composed of 17.5% glycerol + 17.5% sucrose in Murashige and Skoog (MS) medium for 40 min at 25℃. Prior to direct immersion in LN for 1 h, the shoot tips were dehydrated with plant vitrification solution 2 (PVS2) at 0℃ or PVS3 at 25℃. The frozen shoot tips were re-warmed and unloaded with 1.2 M sucrose in ½ MS for 30 min at 25℃. Shoot tips were post-cultured overnight on survival medium and then micrografted onto ‘trifoliate orange’ (Poncirus trifoliate (L.) Raf. seedling rootstocks for recovery and to produce whole plants. The highest regrowth rates were 53.5% and 50.3% for cryopreserved shoot tips of ‘Frost Eureka limon’ and ‘Cook Eureka limon’, respectively, when pre-cultured in 0.3 M and 0.5 M sucrose concentrations in a sequencing manner, with LS and treated with PVS2 for 60 min at 0℃. We also investigated whether the ammonium ion concentration on post-culture medium affected the viability of the cryopreserved Citrus shoot tips. The viability of cooled samples, following culturing on woody plant media (WPM) containing ¼ ammonium nitrate overnight before micrografting, was the highest (70.3%) in ‘Frost Eureka limon’. The study described here is a cost-effective and safe method to conserve Citrus fruit cultivars, for the improvement and large-scale multiplication of fruit plants and for breeding disease resistance.

This study describes an efficient and widely applicable droplet-vitrification following cryopreservation for shoot tips of Chrysanthemum morifolium (Ramat.) cvs. ‘Borami’ and ‘Yes morning’. The shoot tips of Chrysanthemum were precultured in Murashige and Skoog (MS) liquid medium supplemented with sucrose (0.3-0.7 M). Precultured explants were treated with loading solution (LS, C6) containing glycerol 20% and sucrose 20% for 30 min and exposed to dehydration solution (B5) containing 40% of glycerol and 40% of sucrose for 60 min at 25℃, and then transferred onto droplets containing 2.5 ㎕ PVS3 on sterilized aluminum foils (4 ㎝ × 0.5 ㎝) prior to direct immersion in liquid nitrogen (LN) for 1 h. The highest regeneration rate (%) was obtained when shoot tips were precultured with treatment-2 (exposing of shoot tips to MS + 0.3M sucrose for 30 h and then treated with MS+0.5 M sucrose for 16 h) at 25℃ in both the cultivars. The viability of cooled samples, followed by culturing on NH4NO3-free MS medium for first 5 days was increased to two-fold (80.7%) regrowth rate over those cultured on normal MS medium or MS medium containing plant growth regulators. This result shows droplet-vitrification would be a promising method for cryobanking chrysanthemum germplasm.

Garlic (Allium sativum L.) has been used as both food and medicine in many cultures for thousands of years. Garlic cultivars are completely sterile and propagated through vegetative method. Collection of a large number of fertile accessions of these genus is needed to explore genetic variability. In order to investigate genetic variation among Allium species and its possibilities for direct cultivation in Korea, we characterized 12 accessions of A. longicuspis, flowering wild garlic which had collected from Central Asia, the main center of garlic diversity. Most of A. longicuspis accessions showed higher over-wintering and bolting rate, longer scape length and more number of bulbils than Korean landraces cultivar, Danyang and Euiseong, but A. longicuspis accessions exhibited smaller size of bulbs and bulbils. Most accessions of A. longicuspis had more number of cloves per bulb, except K229596 and K248824 than Korean landraces. All the accessions of A. longicuspis from Central Asia had complete bolters having many flowers and topsets in umbel. Further studies of A. longicuspis should focus on securing true seeds through removal of topsets and crosses among accessions to create the genetic variability.

Potato virus Y (PVY) and potato leafroll virus (PLRV) are among the most damaging potato viruses and prevalent in most potato growing areas. In this study, cryopreservation was used to eradicate PVY and PLRV using two cryogenic methods. Potato shoot tips proliferated in vitro were cryopreserved through droplet-vitrification and encapsulation-vitrification using plant vitrification solution 2 (PVS2; 30% glycerol + 15% dimethyl sulfoxide + 15.0% ethylene glycol + 13.7% sucrose) and modified PVS2. Both cryogenic procedures produced similar rates of survival and regrowth, which were lower than those from shoot tip culture alone. The health status of plantlets regenerated from shoot tip culture alone and cryopreservation was checked by reverse transcription-polymerase chain reaction. The frequency of virus-free plants regenerated directly from highly proliferating shoot tips reached 42.3% and 48.6% for PVY and PLRV, respectively. In comparison, the frequency of PVY and PLRV eradication after cryopreservation was 91.3~99.7% following shoot-tip culture. The highest cryopreserved shoot tip regeneration rate was observed when shoot tips were 1.0~1.5 mm in length, but virus eradication rates were very similar (96.4~99.7%), regardless of shoot tip size. This efficient cryotherapy protocol developed to eliminate viruses can also be used to prepare potato material for safe long-term preservation and the production of virus-free plants.

Soybean (Glycine max L.) is crucial legume crop as source of high quality vegetable protein and oil, and Korea is regarded as a part of center of soybean origin. To expand the information of conserved genetic diversity, we analyzed the genetic variability of soybean collection mainly introduced Korean accessions using 75 microsatellite markers. A total of 1,503 alleles with an average value of 20.0 alleles were detected among 644 accessions. Korean collection revealed average allele number of 13.4 while Chinese, Japanese and Southeast Asian accessions showed 9.0, 5.4 and 6.5 mean alleles, respectively. Especially, Korean accessions showed more number of private allele per locus as 3.4 contrary to other geographical groups. The mean expected heterozygosity and polymorphic information content was 0.654 and 0.616, respectively, and expected heterozygosity values were not significantly distinguished according to the geographical groups. The phylogenetic dendrogram and deduced population structure based on DNA profiles of 75 SSR loci showed Korean accessions formed distinct gene pool against Chinese accessions, and could be divided into five subpopulations. Korean soybean accessions have specific genetic diversity and might be serve the valuable alleles for bio-industry as a part of the center of soybean origin.

인삼 개갑종자의 초저온보존 효과 및 최적조건을 구명하기 위하여 건조 조건과 수분함량 및 액체질소 보존 전 동결처리와 보존 후 해동처리에 따른 초저온보존 효과를 조사하였다. 건조처리는 25℃ air flow 챔버(RH 10～12%)와 15℃ 건조실(RH 22～25%)을 이용하여 실시하였고 보존 전 동결은 –24℃에서 30일간 처리하였으며 보존 후 해동은 4℃에서 24시간, 40℃에서 2분 처리구를 각각 비교하였다. 그 결과 15℃에서 종자수분 8-12%로 건조된 종자가 보존 전 처리 없이 액체질소에 보존된 후 40℃에서 해동되었을 때 발아율이 가장 높은 것으로 나타났다. 그러나 종자수분이 2.2% 이하일 때 건조가 지속되면 발아율은 감소하는 것으로 나타났으며, 4% 이하에 이르면 보존 전후 처리효과는 나타나지 않는 것으로 조사되었다. 반면 25℃에서 건조된 종자는 상대적으로 높은 발아율을 유지하였다. 건조 및 초저온보존에 의한 인삼 개갑 종자의 유근 및 자엽 생장율을 조사한 결과, GA배지 치상 10일 후 무처리한 대조구에서 첫 유근이 출현하였으며 3주 후에는 자엽발달이 시작되었다. 30일째에는 자엽생장율이 유근발달과 함께 유의하게 증가하는 것으로 나타났다. 치상 30일까지 초저온보존에 의한 생장율은 같은 양상을 보이면서 대조구보다 현저히 낮게 나타났으나 40일째에는 양상은 같았으나 회복율이 대조구보다 증가세를 보였다. 또한 보존 전 동결처리 없었던 종자는 동결처리한 종자보다 모든 처리구에서 높은 유근 및 자엽 생장율을 보였다.

Rice (Oryza sativa L.) is important crop as a staple carbohydrate sources and was regarded as domesticated in Asia region. The seed dormancy is one of the domesticated traits, and this character allows that plants survive in various environment. The degree of dormancy have been targeted for controling in breeding program while weak dormancy cause pre-harvest sprouting contrary to the nonuniform seed germination by strong dormancy. In this study, we surveyed the variation of germiability in diverse rice genetic resources including japonica and indica ecotype. Overall, the degree of seed dormancy of rice germplasm was distinguished into four groups and admixed types; first group(G-1) included accessions revealing high germiability, the accessions of second group(G-2) acquired the high germiability by after-ripening process, third group(G-3)’s accessions showed high germiability after dormancy breaking process and the accessions of last group(G-4) maintained the low germiability in spite of the dormancy breaking process. Among the 51 japonica accessions G-1, G-2, G-3 and G-4 included 15, 15, 11 and 10 accessions, respectively, and among 40 indica accessions, G-1, G-2, G-3 and G-4 groups included 15, 15, 9 and 1 accessions, respectively. Based on these primary test, we plan to detail examine the seed germiability and survey the genetic factors affecting the degree of germiability in representative accessions of each group

It is very crucial to evaluate the genetic diversity of peanut genetic resources for identification of peanut germplasm accessions and variety improvement. Cultivated peanut generally has two subspecies, hypogaea and fastigiata. In this study, we identified peanut into three plant types, virginia (var. hypogaea), spanish (var. vulgaris), and valencia (var. fastigiata). Former one belongs to ssp. hypogaea and latter two are involved in ssp. fastigiata. Twenty SSR markers were used to assess the genetic variation of three sets, hypogaea, vulgaris, and fastigiata, respectively. Out of variety-specific SSR primers tried in this study, ten pairs of SSR primers showed polymorphisms. Each accession could be identified by a specific set of polymorphic SSR primers, and allele number was evaluated among accessions, with an average of 6.7 in var. hypogaea and 5.4 in var. vulgaris and fastigiata. For evaluation of genetic diversity, gene diversity ranged from 0.336 to 0.844 and PIC (polymorphism information contents) ranged from 0.324 to 0.827 were investigated. Dendrograms based on genetic distances were constructed, which showed the existence of three different clusters. And these three different clusters might be associated with the genes involved in three plant types. The results also suggested that there were plentiful SSR polymorphisms among peanut germplasm accessions in RDA (Rural Development Administration, Korea) Genebank and SSRs might play an important role in evaluating peanut accessions and cultivar improvement.