• Plant Biotechnology Reports
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• v.5 no.1
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• pp.71-77
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• 2011

Drought and salinity are the most important abiotic stresses that affect the normal growth and development of plants. Glycine betaine is one of the most important osmolytes present in higher plants that enable them to cope with environmental stresses through osmotic adjustment. In this study, a betaine aldehyde dehydrogenase (BADH) gene from spinach under the control of the stress-induced promoter rd29A from Arabidopsis thaliana was introduced into potato cultivar Gannongshu 2 by the Agrobacterium tumefaciens system. Putative transgenic plants were confirmed by Southern blot analysis. Northern hybridization analysis demonstrated that expression of BADH gene was induced by drought and NaCl stress in the transgenic potato plants. The BADH activity in the transgenic potato plants was between 10.8 and 11.7 U. There was a negative relationship (y = -2.2083x + 43.329, r = 0.9495) between BADH activity and the relative electrical conductivity of the transgenic potato plant leaves. Plant height increased by 0.4-0.9 cm and fresh weight per plant increased by 17-29% for the transgenic potato plants under NaCl and polyethylene glycol stresses compared with the control potato plants. These results indicated that the ability of transgenic plants to tolerate drought and salt was increased when their BADH activity was increased.

• Korean Journal of Plant Resources
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• v.23 no.3
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• pp.233-241
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• 2010

In vitro elimination of Sweet potato leaf curl virus (SPLCV) from infected sweet potato is difficult due to low number of virus-free plants obtained from meristem tip culture and long growth period required for the virus detection. In this study, efficient production of the SPLCV-free sweet potato by in vitro therapy coupled with a PCR assay for virus detection was investigated. Infected shoots cultured on Murashige and Skoog medium were treated at three different temperatures for 7 weeks followed by meristem tip culture on the medium with or without ribavirin at 50 mg/L. The regenerated plantlets were tested for virus infection by a PCR assay. The results showed that the both heat- and cold-treatments, and addition of the ribavirin did not have significant effect on efficiency of the virus elimination. The meristem size, however, greatly affected the survival rate. Meristems sized over 0.4 mm survived better than smaller ones (0.2-0.3 mm). The PCR assay was approved to be a rapid, sensitive and reliable for the SPLCV detection in regenerated plantlets. Therefore, combination of cultivating meristem tips sized 0.4-0.5 mm on the medium at $22^{\circ}C$ without ribavirin and detection of SPLCV in the regenerated plantlets by the PCR assay was an efficient system for the SPLCV elimination from infected sweet potato.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.85-85
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• 2017

Potato is important carbohydrate source over the world in that revealing high productivity per the unit area, and their cultivation area is estimated to be increased to cope with a scarcity of food according to the population increase. Major cultivated species of potato is Solanum tuberosum (2n = 4x = 48) and regarded as being originated in Andes region of South America. The diverse potato genetic resources has been collected and perserved in Highland Agricultural Research Institute (NICS, RDA), and the genetic materials as DNA stock is conserved in National Agrobiodiversity Center(NAS, RDA). The understanding of genetic constitution of conserved diversity is the basis for the germplam management and further utilization. In this study, we analyzed the genetic diversity of potato germplasm(479 accessions) using 24 microsatellite markers which have been internationally used for fingerprinting of potato accession. The allele number and polymorphic information content (PIC) of total accessions per locus was ranged from 2 to 18 (mean = 8.2) and from 0.214 to 0.771 (mean = 0.595), respectively. Especially, the accession originated from Korea revealed average allele number of 6.0 (2 - 11) and average PIC value of 0.58 (0.193 - 0.763). Three groups were deduced by phylogenic analysis (Group-1, -2, -3); Korean accessions showed close genetic similarity to Japanese and USA accessions, and Korean landraces were mainly included in Group-3. We try to elaborate the genetic diversity analysis of conserved potato germplasm by acquiring more genotypes using applicable molecular markers.

• The Plant Pathology Journal
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• v.33 no.5
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• pp.467-477
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• 2017

A nationwide survey was performed to investigate the current incidence of viral diseases in Korean sweet potatoes for germplasm and growing fields from 2011 to 2014. A total of 83.8% of the germplasm in Korea was infected with viruses in 2011. Commercial cultivars that were used to supply growing fields were infected at a rate of 62.1% in 2012. Among surveyed viruses, the incidence of five Potyvirus species that infect sweet potato decreased between 2012 and 2013, and then increased again in 2014. Representatively, the incidence of Sweet potato feathery mottle virus (SPFMV) was 87.0% in 2012, 20.7% in 2013 and then increased to 35.3% in 2014. Unlike RNA viruses, DNA viruses were shown to decrease continuously. The incidence of Sweet potato leaf curl virus (SPLCV) was 5.5% in 2003, 59.5% in 2011, and 47.4% in 2012. It then decreased continuously year by year to 33.2% in 2013, and then 25.6% in 2014. While the infection rate of each virus species showed a tendency to decline, the virus infection status was more variable in 2013 and 2014. Nevertheless, the high rate of single infections and mixed infection combinations were more variable than the survey results from 2012. As shown in the results from 2013, the most prevalent virus infection was a single infection at 27.6%, with the highest rate of infection belonging to sweet potato symptomless virus-1 (SPSMV-1) (12.9%). Compared to 2013, infection combinations were more varied in 2014, with a total of 122 kinds of mixed infection.

• Proceedings of the Korean Society of Crop Science Conference
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• 2021.10a
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• pp.190-190
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• 2021

• Journal of The Korean Society of Grassland and Forage Science
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• v.17 no.1
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• pp.1-10
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• 1997

Unreduced (2n) gametes are meiotic products (pollen or egg) having a sporophytic (somatic) chromosome number, resulting from abnormalities during either microsporogenesis or megasporogenesis. They occur naturally at a low frequency in many plant species. Unreduced (2n) gametes in plants can be identified for four possible ways as follow i) pollen size and/or shape differences between haploid (n) and diploid (2n) pollen, ii) ploidy analysis (chromosome number) of progeny or meiotic analysis (presence of dyads andlor triads at the microspore stage), iii) progeny performance and fertility and iv) dosage of isozyme and DNA markers. Unreduced (2n) gametes can be an effective breeding tool in synthesizing new cultivars, providing a unique method to maximizing heterozygosity, i.e., transferring a large proportion of the non-additive genetic effects (intra- and inter- locus interactions) h m parent to offspring and can also be used to overcome infertility of interploidy crosses. Sexual polyploidization through 2n gametes has been a major route to the formation of naturally occurring polyploids. The three mechanisms of 2n pollen formation in potato have been discovered as follow: i) parallel spindles (ps) or tripolar spindles (ts), ii) premature cytokinesis (pc-I, pc-2) and iii) synaptic mutants (sy-2, sy-3, sy-4). Genetic analysis indicated that the mechanisms of 2n gamete formation were controlled by single recessive gene in potato, alfalfa, red clover, etc., and by two recessive genes in wheat. The use of 2n gametes which can efficiently transfer germplasm fiom wild relatives to cultivated species, especially fiom diploid to tetraploid could make a contribution to the improvement of germplasm base in breeding programs.

• Horticultural Science & Technology
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• v.16 no.4
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• pp.508-510
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• 1998

This study was carried out to establish the in vitro culture system of potato germplasms for minimizing the occurrence of variation and maximizing the culture period. We used osmoticum such as sorbitol or mannitol with sucrose in the absence of plant growth regulators. The growth of potato germplasms in the medium containing osmoticum was increased when the growth temperature was lowered. After six months storage in low temperature, plant heights of tetraploid was somewhat higher than those of diploid with the exception of stn-16 and the difference due to media was not observed. But after twelve months storage, survival rates of plants cultured in LSM 1(sucrose and sorbitol) was higher than those of plants cultured in LSM 2(sucrose and mannitol). The survival rate of stn-16, diploid wild species, was approximately 75% and it was considerably high. In Atlantic, tetraploid cultivated variety, every individual was survived.

• Korean Journal of Plant Resources
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• v.30 no.3
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• pp.298-310
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• 2017

Morphological variation between cultivated and weedy types of Perilla frutescens var. frutescens and P. frutescens var. crispa were studied in 327 germplasm by examining 17 morphological characters. The germplasm between the two varieties were varied for their qualitative and quantitative characters. The seed coat color of cultivated P. frutescens var. frutescens is commonly light brown and brown while deep brown color was observed in the weedy type P. frutescens var. frutescens and P. frutescens var. crispa. The leaf size, cluster length, plant height, flower number per cluster and seed weight in cultivated P. frutescens var. frutescens were significantly (P<0.05) different from weedy type P. frutescens var. frutescens and P. frutescens var. crispa. The cultivated P. frutescens var. frutescens exhibited significantly higher plant height (158.6 cm) compared to the weedy P. frutescens var. crispa (133.8 cm). Likewise, seed weight was significantly higher in cultivated (1.9 g) than in the weedy type of P. frutescens var. frutescens (1.6 g) and P. frutescens var. crispa (1.4 g). Principal component analysis (PCA) result showed that the first and second principal component cumulatively explained 86.6% of the total variation. The cultivated type P. frutescens var. frutescens and its weedy accessions were not clearly separated with P. frutescens var. crispa by PCA. Hence it requires the use of molecular markers for better understanding of their genetic diversity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.3
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• pp.332-339
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• 1996

Electrophoretic method was utilized to classify 100 varieties of sweet potato germplasm maintained at the National Crop Experiment Station of Korea in 1993. The esterase isozyme patterns in the leaves were classified into 14 different types. Type Ⅸ included the most of the varieties (46) tested and Ⅶ, I, III, Ⅷ, II and V types of all included 47 varieties in order. The other 7 varieties had different band pattern with each other. Type I having many kind of band pattern included Shinyulmi, Beniastma and High starch which had the dry type of tuberous roots varieties. The esterase isozymes pattern in the tuberous roots were classified with 18 kinds of types. The C type included 22 varieties and B, K, A, E, I and N in order. The proteins pattern in the tuberous roots were classified with 7 kinds of types. I type included 36 varieties, and IV type included 27 varieties and II, III, Ⅶ and Ⅵ types in order.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.474-481
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• 2011

Potato late blight caused by the fungus Phytophthora infestans is one of the most vital diseases damaging the potato plant. It is for this reason that breeding potato cultivars resistant to late blight is now becoming a major concern around the world. The B3C1 clones has been introduced by the Highland Agriculture Research Center, RDA. The clones which came from International Potato Center in 2005 have a durable resistance to late blight. The clones were bred under a short-day condition in Peru. However, there was still no report on the adaptability of these clones to the long-day condition in Korea. Therefore, this study was conducted to evaluate the late blight resistance and major agronomic characteristics of B3C1 clones under Korea's long-day condition. This study was also done to generate genetic resources for developing new varieties resistant to late blight. In this study it was found out that in naturally infested field with P. infestans, AUDPC (area under disease progress curve) values of all B3C1 clones were significantly lower than those of the control varieties, 'Superior', 'Atlantic', and 'Haryeong'. It was found out that B3C1 clones had a high level of resistance to late blight and that they could be used as genetic resources to breed potato varieties with late blight resistance. However, several undesirable characteristics such as extremely late maturity, excessive growth of stems and stolons, and production of tubers that cannot easily be removed from the stolons were also observed. Among the twenty B3C1 clones, two clones, LB-8 (CIP393077.159) and LB-11 (CIP393371.159), were selected for cultivating at the highland area of Korea. Two B3C1 clones were crossed with Korean breeding lines and clonal selection for the progenies is still in progress.