• Research in Plant Disease
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• v.17 no.1
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• pp.95-98
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• 2011

This research was carried out to selection of desirable cultivar for organic cultivation of carrot in Korea. The assay of disease resistance, insect tolerance and rate of bolting were investigated on 32 cultivars of genetic resources of carrot. This experiment was carried out at experimental field and greenhouse of Gangneung-Wonju National University. 'PI 223360' was resistant against powdery mildew. Ten cultivars including 'Oxheart Carrot Heirloom' were moderately resistant, 22 cultivars including 'Long Impeator #58' were susceptible to powdery mildew. Although there was no resistant cultivar against black rot and leaf blight, our results showed that several cultivars have moderate resistance. Thirteen cultivars including 'Oxheart Carrot Heirloom' were having insect (Erythroplusia pyropia) tolerance and 'SA 102' and 'Scarlet Keeper Carrot Rare' were susceptible. According to the investigation of bolting, 6 cultivars including 'Hongsim Ouchon Carrot' were early bolting and 4 cultivars including 'Japanese Imperial Long Carrot' were moderate bolting. Other cultivars were identified as late bolting. From above results, we confirmed that 'Oxheart Carrot Heirloom' was suitable cultivar for organic cultivation among 32 genetic resources of carrot.

• The Plant Pathology Journal
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• v.31 no.4
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• pp.441-445
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• 2015

Carrot (Dacus carota var. sativus) is one of the top-ten most economically important vegetable crops produced worldwide, and the root-knot nematodes, Meloidogyne spp., are one of the most important pests in the carrot. In Korea, M. hapla and M. incognita are presumed to be the major root-knot nematodes distributing mostly in open carrot fields and greenhouses, respectively. In our study, currently-developed and commercial carrot cultivars and the parental lines were examined for their pathological responses to M. incognita and M. hapla 7 weeks after inoculation with about 1,000 second-stage juveniles (J2) of the nematodes. All the carrot cultivars and lines showed susceptible responses to both nematodes with the gall index (GI) of 2.4-4.4, which were always higher on the carrot plants infected with M. incognita than M. hapla. Gall sizes were remarkably larger with more serious reduction of the root growths in the plants infected with M. incognita than M. hapla, suggesting the carrot lines examined in our study were more susceptible to the former than the latter. In the infection sites of the root tissues, giant cells were more extensively formed, occupying larger stellar regions with the prominent destruction of adjacent xylem vessels by M. incognita than M. hapla. All of these results suggest M. incognita affect more seriously on the carrot plants that are grown in greenhouses, compared to M. hapla that has a major distribution in open carrot fields, which would be used for determining cropping systems based on target nematode species, their damage and pathological characteristics.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.75-81
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• 2014

In total, 170 carrot lines developed in Korea were screened for resistance to Meloidogyne incognita race 1 to select parental genetic resources useful for the development of nematode-resistant carrot cultivars. Using the gall index (GI), gall formation was examined on carrot roots inoculated with approximately 1,000 second-stage juveniles of the nematode 7 weeks after inoculation. Sixty-one carrot lines were resistant (GI ${\leq}1.0$), while the other 109 were susceptible (GI > 1.0) with coefficient of variance (CV) of GI for total carrot lines 0.68, indicating low-variation of GI within the lines examined. The histopathological responses of two carrot plants from resistant and susceptible lines were examined after nematode infection. In susceptible carrots, giant cells formed with no discernible necrosis around the infecting nematodes. In the resistant carrot line, however, no giant cells formed, although modified cells were observed with extensive formation of necrotic layers through their middle lamella and around the infecting nematodes. This suggested that these structural modifications were related to hypersensitive responses governed by the expression of true resistance genes. Therefore, the Korean carrot lines resistant to the nematode infection are potential genetic resources for the development of quality carrot cultivars resistant to M. incognita race 1.

• Journal of Environmental Science International
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• v.18 no.10
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• pp.1135-1141
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• 2009

Carrots (Daucus carota L.) are consumed as an important dietary source of provitamin A including $\beta$-carotene, $\alpha$-carotene and lutein. An HPLC method was applied to determine the content of the carotenoid composition in carrot cutivars cultivated in Korea. HPLC analyses were carried out with five carrot cultivars (Socheon-5-chon, Hongsim-5-chon, Myeongju-5-chon, Seonhongbom-5-chon and Betarich) sown at April, 2007 and six cultivars (Yeoreum-5-chon, Hanyeoreum-5-chon, Sinheukjeon-5-chon, Bibariheukjeon, Manina and Betarich) sown at August of the same year. In general, the former varieties are not used for the sowing at summer because of their bolting (growth of floral axis). The former and the latter carrots were harvested after 110 and 96 days from seeding, respectively, and the carotenoids were extracted with acetone after freeze-drying. The amount of $\alpha$-carotene ($117.7{\sim}205.3\;{\mu}g/g{\cdot}DW$) was similar to that of $\beta$-carotene ($113.1{\sim}189.6\;{\mu}g/g{\cdot}DW$) for the carrot cultivars sown at spring, while the content ($46.2{\sim}71.1\;{\mu}g/g{\cdot}DW$) was about a half of $\beta$-carotene content ($92.5{\sim}140.2\;{\mu}g/g{\cdot}DW$) for the latter cultivars. In addition, the average content of lutein ($25.2\;{\mu}g/g{\cdot}DW$) in the former cultivars was eight times higher than that in the latter cultivars ($3.1\;{\mu}g/g{\cdot}DW$). Among the spring cultivation types, Socheon-5-chon and Myeongju-5-chon showed higher amount of $\alpha$-carotene and $\beta$-carotene, while the higher amount was determined in Yeoreum-5-chon and Sinheukjeon-5-chon among the autumn cultivation types. Validation of the HPLC-DAD method showed good linearity ($r^2$ > 0.997) of the three compounds analyzed in a wide concentration range ($0.025{\sim}20\;{\mu}g/ml$). The R.S.D. values for intra-day and inter-day precision were less than 19.2% and the mean recovery of each compound was 85.4~104.7%.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.536-540
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• 1997

Volatile terpenoids of carrots were measured by the direct headspace sampling method(DHS) with gas chromatography as a study for the breeding of high quality carrots. Using this method, 7 terpenoids such as ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, and terpinolene were clearly separated. However ${\alpha}-phellandrene$ was not clearly separated from ${\beta}-myrcene$. In addition to this, higher boiling point compounds such as terpinen-4-ol, bornyl acetate, and ${\alpha}-bisbolol$ were not found. The coefficients of $determination(r^2)$ for the 7 terpenoids were higher than 0.99 and the standard curves were highly significant. Four replicated samples using this method demonstrated great reproducibility; the coefficidnt of variation (C.V.) for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were 6.8, 6.8, 8.4, 7.1, 3.8, 10.1, 7.1%. Sixty five carrot cultivars breeded worldwide were evaluated for the 7 terpenoids and total terpenoids; the range for ${\alpha}-pinene$, ${\beta}-pinene$, ${\beta}-myrcene$, ${\alpha}-terpinene$, limonene, ${\gamma}-terpinene$, terpinolene, and total terpenoids were $0.28{\sim}2.48\;ppm$, $0.35{\sim}1.87\;ppm$, $0.56{\sim}1.51\;ppm$, 0 ppm, $0.59{\sim}1.84\;ppm$, $0.87{\sim}3.33\;ppm$, $5.15{\sim}35.81\;ppm$, and $9.07{\sim}42.30\;ppm$, respectively. Big differences in each terpenoid and total terpenoids were found among cultivars. On the total terpenoids of the 65 cultivars, 5 cultivars(7.7%) contained less than 10 ppm, 15 cultivars (23.1%) $10{\sim}11.99\;ppm$, 14 cultivars(21.5%) $12{\sim}13.99\;ppm$, 9 cultivars(13.8%) $14{\sim}15.99\;ppm$, 10 cultivars(15.4%) $16{\sim}17.99\;ppm$, 4 cultivars(6.2%) $18{\sim}19.99\;ppm$, 5 cultivars(7.7%) $20{\sim}29.99\;ppm$, and 3 cultivars(4.6%) were higher than 30 ppm. Generally, cultivars developed in Japan contained less total terpenoids than cultivars developed in Europe and America.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.505-510
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• 2001

To improve germinability of carrot seeds of 'Inari', 'Mansan', 'Mussang', and 'Hongsim' cultivars, various levels of solid matrix priming (SMP) and the physiological changes of seeds associated with SMP were examined. As the ratio of water in a seed-Micro Cel E-water mix and priming duration increased, seed germinability enhanced. However, there was radicle protrusion during SMP in some cultivars, indicating the existence of cultivar different variations of the optimum conditions. The optimum ratio for a seed-Micro Cel E-water mix was 5 : 3 : 10.5. In this mix, the optimum durations for the treatment were 3 days for 'Mansan' and 5 days for other cultivars. SMP at $20^{\circ}C$ to $25^{\circ}C$ resulted in a higher germination percentage and a shorter $T_{50}$. Seeds absorbed water quickly within an hour and the percentage of moisture was stable at 43 to 49 after 24 hours of the treatment. Conductivity of the mix declined for the first 6 hours to $100{\mu}S{\cdot}cm^{-1}$ with little changes thereafter. On the other hand, the pH of the mixed increased slightly during the early phase, and then returned to the initial level as the treatment proceeded.

• Korean journal of applied entomology
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• v.55 no.4
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• pp.389-403
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• 2016

Sugar beet nematode (Heterodera schachtii Schmidt) was first detected in 2011, in Chinese cabbage grown in the highland areas of Korea. Chemical control of the nematode by nematicides is not feasible due to its cyst-forming characteristics; therefore, the cultivation of non-host crops is a preferable alternative to utilize nematode-infected fields. In this study, a total of 276 plant cultivars belonging to 18 different families were screened to evaluate their resistance to the nematode. Based on the number of cysts formed following nematode inoculation, the tested crops were classified into 3 levels: susceptible, moderately susceptible, and resistant/immune. Among the 276 cultivars tested, 106 cultivars were susceptible, 40 cultivars were moderately susceptible, and 130 cultivars were resistant/immune. Among the resistant/immune cultivars, cyst formation was not observed on eggplant, tomato, lettuce, perilla, carrot, celery, watermelon, oriental melon, cucumber, pumpkin, chives, onion, welsh onion, balloon flower roots, deodeok (Codonopsis lanceolata), Jandae (Adenophora triphylla), and bean. Therefore, these plants are regarded as immune to the cyst nematode. However, many crops belonging to Solanaceae, Asteraceae, Chenopodiaceae, and Poaceae families showed moderate susceptibility or immunity, depending on the crop or cultivar. This study provides a basis for alternative crop recommendations for sugar beet nematode cyst-infected farms in Chinese cabbage production areas.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.782-789
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• 2013

Carrot (Daucus carota L. var. sativa) is one of the most widely used crops in the world and is nutritionally important crop. However, seed-hair which is generated in epidermal cell of seeds causes the difficulty of the seedling process, because of the seed germination and absorption inhibitions. For these reasons, carrot seeds are commercialized after mechanical hair removal process. However, in this process, various damage and seed loss occur and breeding of hairless-seed carrot cultivar is needed to overcome these various weaknesses and additional seed production costs. In this study, cDNA libraries using 2 combinations, which were composed of short-hair seed CT-ATR 615 OP 666-13 & long-hair seed CT-ATR 615 OP 671-9, and short-hair seed CT-SMR 616 OP 659-1 & long-hair seed CT-SMR 616 OP 677-14, were constructed and EST sequences of each individuals were analyzed to reveal carrot seed-hair characteristics. Firstly, analyzed EST sequences were classified into FunCat functional categories. As a result, significant differences have been identified in metabolism category, protein folding and stabilization, protein binding, C-compound binding category from both of two combinations. Secondly, several candidate EST sequences related to seed trichome differentiation and cellulose biosynthetic process were selected based on GO data of EST sequences. These differences based on FunCat categories and candidate EST obtained by GO data analysis are thought to be involved in the formation of carrot seed hair. Finally, 741 SSR sites and 33 SNP sites were identified from analyzed EST sequences of two combinations. Then we designed SNP and SSR primer sets to develop molecular markers. These molecular markers will be used for classification of carrot cultivars and study seed-hair characteristic.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.511-514
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• 2001

Pelleting the seeds often reduces seed germinability. In an effort to alleviate this problem, the seeds of four carrot cultivars were, before pelleting, either solid-matrix primed (SMP) with Micro Cel-E or osmotically-primed with polyehtylene glycol 8000. Some batches were imbibed in 100-ppm $GA_3$ solution. In laboratory tests, pretreatment of the seeds increased the precentages of germination by as much as 50% of the controls, indicating the increase of the germination speed by 1.9 to 4.6 days as determined by the $T_{50}$ values. In field tests conducted in the year of 2000 and 2001, however, effects of SMP were not observed. There was no significant difference between the SMP seeds and the controls of the percentages and $T_{50}$ values. The emergence of the seedling in the field was affected greatly by soil water concentration.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.756-763
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• 2013

Mechanical hair removal of carrot seed causes seed injuries and suppresses the germination in carrot cultivation. This study was performed to develop molecular markers for breeding high quality cultivars with short-hair seed. To meet this objective, random amplified polymorphic DNA (RAPD)-sequence characterized amplified region (SCAR) markers specifically linked to seed-hair characteristic were identified using CT-SMR 616 OP 389-1 line with short-haired seed and CT-SMR 616 OP 616-33 line with long-haired seed, bred by self-pollination for 6 years from 2008 to 2013, as parents. After seed hair lengths of these lines were analyzed using microscope, next generations were advanced and compared with the molecular markers polymorphism. From RAPD analysis using fixed lines in 2011, twelve RAPD primers showing polymorphic bands specific between the two lines were identified from 80 random primers. To develop RAPD-SACR marker, SCAR primers were designed based on sequence analysis of these specific RAPD bands and more than three combinations of primers were tested. As a result, it was found that the $SCA2_{1.2}$ amplified single polymorphic band from short-haired seed line. To confirm this result, $SCA2_{1.2}$ marker was retested by applying to the 2012 and 2013 progenies. Finally, it was concluded that the developed $SCA2_{1.2}$ marker distinguished short-haired line from long-haired seed line. Therefore, SCAR marker, $SCA2_{1.2}$ is expected to be utilized for breeding of the short-haired seed cultivars.