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Yeh-Jin Ahn and Na-Hyun Song

under various abiotic stresses, where DcHsp17.7 in carrot ( Daucus carota L.) was expressed under conditions of heat ( Kim and Ahn, 2009 ), cold ( Song and Ahn, 2010 ), and salinity ( Song and Ahn, 2011 ). Furthermore, the heterologous expression of

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Hanseul Park and Yeh-Jin Ahn

Center for Biotechnology Information (NCBI) accession no.: NC_000913.2] promoter, an Hsp17.7 gene from carrot ( Daucus carota L.; NCBI accession no.: X53851) and flippase-recombinase targets (Frt) cassette were generated by polymerase chain reaction

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Adam Bolton and Philipp Simon

accumulating in the soil ( Rozema and Flowers, 2008 ). Most crops, including cultivated carrot ( Daucus carota var. sativus ), are categorized as glycophytic plants. The growth of glycophytes is greatly reduced in saline soils because they lack physiological

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Adam Bolton, Aneela Nijabat, Muhammad Mahmood-ur-Rehman, Naima Huma Naveed, A.T.M. Majharul Mannan, Aamir Ali, Mohamed A. Rahim and Philipp Simon

the productivity of most vegetables have yet not been well-characterized ( Fahad et al., 2017 ; Mahmood et al., 2017 ). It may be anticipated that cool-season vegetables, like carrot, are especially sensitive to heat stress. Carrot ( Daucus carota L

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Chano H. Kim, Jonq H. Park, In S. Chung, Sung R. Kim and Seung W. Lee

Secondary metabolite production by plant cell culture has been become of interest because of its commercial value in use. However, cultured plant cells usually yield lower levels of secondary metabolites than those of intact plants. In order to improve the anthocyanin productivity in hairy root culture of Daucus carota, fungal elicitors from 8 species of Fungi were examined. Through the studies of fungal elicitors in this work, it was turned out that fungal elicitors were very effective to improve the yield of anthocyanin. Despite of its low yield of anthocyanin, high density culture of hairy roots is achieved in fluidized-bed bioreactor, Anthocyanin production in fluidized-bed bioreactor with fungal elicitor treatment was increased greatly. We are currently researching more detailed aeration effects and scale-up in air-lift bioreactors. And these studies could provide important data to establish mass production system for secondary metabolites.

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Michael E. Bartolo and Frank C. Schweissing

Parts of Colorado receive more hail than almost any other area in the nation. Severe storms can injure crop tissue and, thus, lower yield and predispose the crop to disease infection. Our study was conducted to determine the yield and quality response of carrot (Daucus carota L.) to simulated storm damage during different periods of plant development. We removed 33% and 67% of the carrot foliage at four dates, spaced 10 days apart, during the middle of the growing season. In 1997 and 1998, 67% defoliation significantly reduced total and marketable yields more than did 33% defoliation. Total yield components, length and diameter, were similarly affected. Defoliation, in general, decreased yield the greatest when it when it occurred at the later stages of development. Carrot foliage continued to develop and grow after all defoliation events. Nonetheless, moderate (33%) and severe (67%) foliage loss reduced marketable yield and yield components of carrots.

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Keun Ho Cho, Chiwon W. Lee, Larry J. Cihacek, Robert W. Stack and Hoon Kang

The influence of calcium (Ca++) nutrition on the growth and root tissue electrolyte leakage (EL) of carrot (Daucus carota) was investigated using a hydroponic culture system. Seedlings of `Navajo' carrot were grown for 10 weeks with roots submersed in hydroponic nutrient solutions containing 0, 0.1, 1, 2, 4, or 8 meq/L Ca++. The nutrient solution was replenished weekly with its pH maintained at 5.8 for the entire experimental period. The tap root lengths increased as solution Ca++ concentration increased. The diameter and fresh and dry weights of the tap roots increased as Ca++ concentration increased up to 4 meq/L, and then decreased at 8 meq/L Ca++. The root and petiole concentrations of sugar, potassium, and nitrate were unaffected by changes in nutrient solution Ca++ levels. The tissue EL, when tested for the stored roots, decreased as solution Ca++ concentration increased (r = 0.602). Results of this experiment suggest that calcium nutrition is essential for maintaining cell wall integrity in hydroponically grown carrot roots.

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Min Wang and I.L. Goldman

The root-knot nematode (M. hapla Chitwood) poses a threat to carrot (Daucus carota L.) production in the United States. Little information is available concerning the genetic control of nematode resistance in carrot. Crosses between two inbreds, a resistant genotype (R1) and susceptible genotype (S1) identified in previous screening tests of carrot were studied in the F2 and BC1 generations to determine the heritability of resistance to the root-knot nematode. Seedlings of F2 (R1/S1), BC1S1, and BC1R1 generations were evaluated for their responses to infestation of M. hapla Chitwood based on gall number per root, gall rating per root, and root rating per root in a greenhouse experiment conducted during 1994. Narrow-sense heritabilities were calculated according to the method of Warner (1952). Narrow-sense heritability was 0.16 for resistance based on gall number, 0.88 for resistance based on gall rating, and 0.78 for resistance based on root rating. This information may be of importance to geneticists and carrot breeders for the development of nematode-resistant carrot cultivars.

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Mingbo Qin, Chiwon W. Lee, Alex Y. Borovkov and Murray E. Duysen

A study was initiated to characterize key enzymes that influence sweetness in carrot (Daucus carota L.) roots. Sucrose synthase (SS), sucrose phosphate synthase (SPS), and UDP-glucose pyrophosphorylase (UDPL) genes were isolated from potato (Solanum tuberosum L.) and cloned in an anti-sense orientation into Agrobacterium tumefaciens Bin19, which has a CaMV 35S promoter. Seedling hypocotyl sections of selected carrot lines were pre-incubated on B5 medium for 2 days, co-cultivated with A. tumefaciens Bin 19 for additional 3 days, and then transferred to a modified B5 medium containing 50 g/mL kanamycin and 400 g/mL carbenicillin. In 4 weeks, 18.6%, 33.3%, and 26.7% of the cultures from a breeding line (W204-C) were found to be transformed, respectively, with SS, SPS, and UDPL as determined by kanamycin resistance. In contrast, no kanamycin-resistant calli were obtained from a commercial cultivar (Navajo) in these transformation studies. The transformed calli proliferated in the medium containing 50 g/mL kanamycin and 400 g/mL carbenicillin, whereas non-transformed calli died in the same medium. These transformed calli are currently being used to regenerate plants via asexual embryogenesis using a suspension culture. The influence of these additional genes on sugar metabolism and accumulation in root tissues of transformed carrots will be characterized in the future.