It is considered necessary to renewal a considerable number of water supply facilities in Korea because they began to be intensively buried in the period of rapid economic growth. Accordingly, local water providers are required to take measures against this situation, but they have currently been caught in a vicious circle of the lack of budget spent in renewing water supply facilities because county-based small-scale local water supply cannot afford to cover annual expenditures with their revenues from water rates. Therefore, this study developed an optimal renewal planning model capable of achieving a balance of financial revenue and expenditure in local water supply using nonlinear programming and furthermore of minimizing the total cost incurred during the analysis. To this end, this study selected the water supply area located in County Y as a research area to build the financial revenue and expenditure and used Solver function provided by Microsoft Excel to use nonlinear programming. As a result, this study developed an optimal renewal planning model minimizing incurred costs in consideration of 6 items in the financial revenue and expenditure. The optimal renewal plan was modeled according to the available annual budget. As a result, this study proposed SICD, a scenario to minimize total costs from the perspective of water suppliers, and SITS, a scenario to minimize the increase in water rates from the perspective of consumers. It can be said that the method proposed in this study is the core of the optimal financial and renewal plans as a final stage of asset management for water supply facilities. Therefore, it is considered possible for local water providers to use the method proposed in this study according to circumstances for the asset management of water supply facilities.

Citrus canker caused by Xanthomonas citri is a notorious disease affecting a decrease in fruit productivity and quality. Citrus export to USA is also prohibited by the disease. Therefore, development of citrus canker resistant variety is essential and exploitation of markers for molecular breeding is urgent. To develop DNA molecular markers, we performed whole genome resequencing for 8 varieties: 4 citrus canker resistant varieties including C. hybrid ‘Kioymi’ and 4 citrus canker susceptible varieties including C. iyo ‘Miyauchiiyokan’. In total, 642 polymorphic SNPs were detected between resistant and susceptible varieties. Of the 642 SNPs, 50 SNPs were preferably selected based on integrative genomics viewer. To apply the markers in a broad range of citrus variety, we performed genotyping with 6 other varieties very well known as citrus canker resistant and susceptible varieties in addition to previous mentioned 8 varieties. Three of the 50 SNPs were identified as a marker to distinguish citrus canker resistant varieties from susceptible varieties. Secondly, we developed molecular markers to apply for F1 lines crossed by ‘Kiyomi’ and ‘Miyauchiiyokan’. Of the 50 SNPs, we identified 2 SNP markers to distinguish between F1 resistant and susceptible lines. One of them is a resistance gene that plays a role in plant defense mechanism. In this study, we developed 5 molecular marker candidates possible to apply for molecular breeding to develop citrus canker resistant variety. We are working on development of candidate markers related to citrus canker.

Citrus canker caused by Xanthomonas citri pv. citri is one of economically important diseases in the citrus industry. The devastating bacterial disease results in unattractive quality and a significant reduction in fruit production. Citrus growers and industry in Korea has been struggling with the serious disease causing the prohibition of export market. Korea also became the top import market for oranges. The development of markers linked to citrus canker resistance is strongly needed. In this study, we investigated molecular markers between ‘Kiyomi’ (Citrus unshiu ｘ C. sinensis), a resistant cultivar, and Natsudaidai (C. natsudaidai), a susceptible cultivar. To develop markers, we focused on structural variation (copy number variation, CNV, and presence/absence variation, PAV). It has been well documented that CNV and PAV of defense-related genes are associated with resistant cultivars. Using a read depth approach following next-generation sequencing, we performed genome-wide analysis of CNV and PAV in two varieties. As a result, 633 genes showing at least two times difference between the mapping reads from two varieties and 61 genes showing presence of the mapping reads in only either one of them were screened. Visual inspection using the Integrative Genomics Viewer (IGV) was performed and experimental validation is being investigated. Interestingly, one of PAV candidates showed polymorphism in ‘Kiyomi’ and ‘Natsudaidai’ as well as other resistant and susceptible cultivars. Our results suggest a necessity for the detection of structural variation and indicate that the candidates may be useful for molecular breeding for citrus canker resistance and understanding disease resistance mechanism.

Ramie (Boehmeria nivea L. Gaudich.) is a hardy perennial herbaceous plant of the Urticaceae family and has been grown as a fiber crop in several countries including Korea for many centuries. Ramie leaves also have been traditionally used as a major ingredient of a type of rice cake called ‘Song-pyun’ in the Southwest area of Korea, especially Yeong-Gwang province. Despite its economic importance, the molecular genetics of ramie have not been studied in detail yet. Genetic resources of ramie were widely collected from domestic local sites by Bioenergy Crop Research Center (RDA) and Yeong-Gwang Agricultural Technology Center. For the systematic and efficient management of the genetic resources, we developed microsatellite molecular markers of ramie. To do this, we generated microsatellite-enriched genomic DNA libraries using magnetic bead hybridization selection method. 216 contigs containing microsatellite repeat motif were generated using nucleotide sequences of 376 clones from the libraries. Primer sets were designed from the flanking sequences of the repeat motif. Finally, we selected 26 microsatellite markers, possibly showing polymorphism among the genetic resources. Results on the genotype analysis of the ramie genetic resources using the microsatellite markers will be presented.