• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.574-578
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• 2009

A new red leaf lettuce (Lactuca sativa L.) cultivar, "Gopungjeokchukmyeon" which has late bolting and good red expression leaf color was developed from a cross between "Andongjeokchukmyeon" (red leaf color and late bolting) and "Dukseomjeokchukmyeon" (high yield). The cross and selection for advanced lines had been done by the pedigree method during 2000-2006. The advanced lines were evaluated for yield and adaptability at several locations in Korea (Gangwon, Kyunggi, Chungbuk, Kyungnam, Jeonnam, Jeonbuk, and Jeju) from 2007 to 2008. The "Gopungjeokchukmyeon" has gray seed color and traverse elliptic leaves. Compared to "Dukseomjeokchukmyeon", marketable yield of "Gopungjeokchukmyeon" was higher by 17% (at 330 g per plant) and Gopungjeokchukmyeon has particularly improved expression of red leaf color in high temperature cultivation in the field. The shelf-life of "Gopungjeokchukmyeon" was three weeks longer than "Dukseomjeokchukmyeon" at $4^{\circ}C$. The anthocyanin and sugar contents of "Gopungjeokchukmyeon" were higher than those of "Dukseomjeokchukmyeon" with 29.4 mg/100 g and 4.8 brix, respectively. The content anthocynin of "Gopungjeokchukmyeon" is about 10 times higher than those of "seomjeokchukmyeon". Furthermore, its taste is better, more crispy, and sweeter than those of "Dukseomjeokchukmyeon", This new cultivar "Gopungjeokchukmyeon" can be harvested all year around even summer cultivation.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.579-582
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• 2009

A new red leaf lettuce (Lactuca sativa L.) cultivar, "Mihong" which has late bolting and deep red leaf color was developed from a cross of "Danhongongchukmyeon" (deep red but early bolting and low yield) and "Hajicheongchukmyeon" (late bolting and high yield). The selection and breeding of advanced lines were done by pedigree method during 2000-2006. The advanced lines were evaluated for yield and adaptability in Korea (Gangwon, Kyunggi, Chungbuk, Kyungnam, Jeonnam, Jeonbuk, and Jeju) from 2007 to 2008. The "Mihong" has gray seed color, traverse elliptic leaves and deep red color. Compared to "Dukseomjeokchukmyeon", marketable yield of "Mihong" was higher by 2% (at 291 g per plant) as a 17.3 ton/ha, but with particularly improved good expression of deep red leaf color in high temperature cultivation in the field. The shelf-life of "Mihong" was three weeks longer than "Dukseomjeokchukmyeon" at $4^{\circ}C$. The amount of anthocyanin content of "Mihong" were higher than with "Dukseomjeokchukmyeon" at 28.9 mg/100 g. Especially the degree of leaf hardness in "Mihong" showed $26.9kg/cm^2$ compared to "Dukseomjeokchukmyeon". therefore, its taste is better, more crispy, and sweeter than "Dukseomjeokchukmyeon" This new cultivar "Mihong" can be cultivated in all year around even if summer time cultivation.

• Journal of Life Science
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• v.23 no.1
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• pp.79-83
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• 2013

A biofertilizer, BIOACTIVE, was manufactured by N-acetyl-thioproline (ATCA) and mineral phosphate solubilizing bacteria. The growth promoting effect of the biofertilizer on lettuce was evaluated under three different pot conditions, and its stability was assessed in the field. According to the results of the pot experiments, plant growth was improved compared with that of control: 128%, 122%, and 153% for the leaf number, leaf length, and leaf mass, respectively. Applying the manufactured biofertilizer increased the concentration of phosphate: 118% and 132% in the cultivation soil and plant cells, respectively. These show that BIOACTIVE may have potential as an effective biofertilizer in agriculture.

• Korean Journal of Environmental Agriculture
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• v.14 no.3
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• pp.253-262
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• 1995

The heavy metal contents of soils which had been contaminated with mine residues and green onion and lettuce which were grown on these soils were analyzed. The results obtained are summarized as follows: 1. Heavy metal contents in the soil where green onion and lettuce died back or were poor in growth were unusually high. 2. Heavy metal contents in the plants grown in the soil of high level of metals were also high, in the order of root > leaf > stem. In case of Mn, however, the content was the highest in the leaf. 3. Contents of Cd, Cu, Zn and Ni in soil were positively correlated with those in plant. In case of Pb, there was no consistent relationship between the contents in soil and plant. 4. Even in the soils where plant growth appeared to be normal the heavy metal contents both in soil and in plant were higher than the national average.

• Korean Journal of Organic Agriculture
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• v.6 no.1
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• pp.63-75
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• 1997

This study aims to find out the devices to minimize the amount of nitrate ingested from kimchi, the main way of vegetable intake for Koreans, and the basic data to deliver to calculate the total daily intake for Korean, investigating the year-round changes of nitrate content in vegetables for Kimche raw material, and changes of nitrate content by salting of chinese cabbage, and stewed kimchi through the use of different cooking methods. The results obtained were summarized as follow: over between 205-6655mg/kg f.w. in chinese cabbage, 480-3970mg/kg f.w. in chinese radish, 157-5820mg/kg f.w. in lettuce and 29-520mg/kg f.w. in cucumber respectively. Therefore it was strongly adviced to introduce the nitrate limit value of vegetables in Korea if the nitrate content in Kimchi should be reduced to meet the nitrate ADI(Acceptable Daily Intake, 219mg60kg b.w) of FAO.WHO, because the nitrate content in Kimchi reflects the nitrate content in vegetables. In order to keep the low nitrate content in Kimchi. it was adviced to remove the outer leaf which contains 2-3 times higher nitrate content compare to the inner leaf at the time of preparation, i.e. chinese cabbage, before the soaking treatment in salt solution for Kimchi making process. The dehydration by soaking treatment in salt solution occurred at 0.9%~4.7% in leaf midrib and more than 13%~24% in leaf blade. The nitrate content after soaking in salt solution was increased 107%~123% compared with before soaking, increasing rates of nitrate content in the outer and inner leaf midrib were higher than those in leaf blade. The increase of nitrate content in salt solution after soaking due to the dehydration of chinese cabbage by soaking treatment. The Kimchi stew(Kimchi JJige) was processed with and without animal oil, but the amount of nitrate in kimchi stew did not decrease both treatments, but it increased after the processing since the water in Kimchi stew has got low by boiling.

• The Plant Pathology Journal
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• v.31 no.3
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• pp.259-268
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• 2015

This study investigated the chemical characteristics and microbial population during incubation of four kinds of aerated compost teas based on oriental medicinal herbs compost, vermicompost, rice straw compost, and mixtures of three composts (MOVR). It aimed to determine the effects of the aerated compost tea (ACT) based on MOVR on the growth promotion of red leaf lettuce, soybean and sweet corn. Findings showed that the pH level and EC of the compost tea slightly increased based on the incubation time except for rice straw compost tea. All compost teas except for oriental medicinal herbs and rice straw compost tea contained more ${NO^-}_3-N$ than ${NH^+}_4-N$. Plate counts of bacteria and fungi were significantly higher than the initial compost in ACT. Microbial communities of all ACT were predominantly bacteria. The dominant bacterial genera were analyzed as Bacillus (63.0%), Ochrobactrum (13.0%), Spingomonas (6.0%) and uncultured bacterium (4.0%) by 16S rDNA analysis. The effect of four concentrations, 0.1%, 0.2%, 0.4% and 0.8% MOVR on the growth of red leaf lettuce, soybean and sweet corn was also studied in the greenhouse. The red leaf lettuce with 0.4% MOVR had the most effective concentration on growth parameters in foliage part. However, 0.8% MOVR significantly promoted the growth of root and shoot of both soybean and sweet corn. The soybean treated with higher MOVR concentration was more effective in increasing the root nodule formation by 7.25 times than in the lower MOVR concentrations Results indicated that ACT could be used as liquid nutrient fertilizer with active microorganisms for culture of variable crops under organic farming condition.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.594-598
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• 2006

The aim of this study was to investigate the prevalence and frequency of food-borne pathogens in unprocessed Products such as grains, tubers, vegetables, and seaweeds. Three hundred and twenty seven samples were purchased from the retail market and the supermarket in the Kyonggi-do and Seoul areas, and washed with running tap water for 4 minutes. The total aerobic bacteria count was approximately 2 to 6 log CFU/g and the highest counts were 6 log CFU/g far lettuce and sesame leaf. The coliform count showed 1-5 log CFU/g and the highest counts were 4 log CFU/g for lettuce and carrot. Escherichia coli was detected in seven samples of white rice, sweet potato, lettuce, sesame leaf, and cabbage. Clostridium perfringens was detected in six samples of brown seaweed, laver, lettuce, and sweet potato. However, Bacillus cereus contamination was found in more than 30% of brown rice, carrot, sweet potato, lettuce and sesame leaf samples, and some of these showed contamination of more than 2.0 log CFU/g. Therefore, these results suggest that pretreatment with sanitizer to remove Bacillus cereus in such products is necessary.

• Research in Plant Disease
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• v.13 no.1
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• pp.66-70
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• 2007

During 1997 and 1998, a new disease of lettuce (Lactuca sativa) was observed on greenhouse-grown plants in Kwangju and Kwangmyung. Lesions on leaves were irregular, small, pale green to black, water-soaked, and 2 to 5 mm in diameter, Coalescing lesions sometimes caused defoliation of older leaves. Isolations made from diseased leaves on yeast extract dextrose calcium carbonate agar yielded nearly pure cultures of a yellow pigmented bacterium typical of a xanthomonad. Two bacterial strains (SL0246 and SL1352) were purified and used for further tests. Pathogenicity of strains was confirmed on 5-week-old lettuce plants injected with bacterial suspensions containing $10^8$ cfu/ml of phosphate buffered saline. The representative Xanthomonas strains isolated from lettuce were compared with a reference strain X. campestris pv, vitians for fatty acid profiles and metabolic fingerprints using GN2 microplate, showing that all outcomes were indistinguishable between the representative and reference strains. This is the first report of bacterial leaf spot and dry rot of lettuce in Korea.

• Horticultural Science & Technology
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• v.35 no.4
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• pp.456-464
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• 2017

We examined the effect of nutrient solution concentration in the second half of growing period on the pre- and postharvest characteristics of two leaf lettuce cultivars, 'Geokchima' and 'Cheongchima'. Plants were grown hydroponically in a deep flow technique (DFT) system at different concentrations of National Horticulture Research Institute hydroponic nutrient solution: 1/2 strength (S), 1S, 2S, and 4S. Lettuce leaf growth, number of leaves, and shoot fresh weight of both cultivars were greatest in plants grown in the 1S treatment. Compared to other treatments, pigment and nutrient ion contents were greater in the 4S treatment. Growth of lettuce was greatest in the 1S treatment, and decreased at higher or lower concentrations of nutrient solution. However, postharvest characteristics such as fresh weight loss, leaf chlorophyll level, and external appearance were better in both cultivars when grown in 2S solution. Variations in weight loss and SPAD values were smallest in the 2S treatment. These results show that the optimal nutrient concentration for growth does not necessarily provide the optimal postharvest storability.

• Plant Resources
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• v.2 no.1
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• pp.16-21
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• 1999

An efficient regeneration system was established by using in vitro plantlets of germinated seedlings from different cultivars of lettuce (Lactuca sativa cv. Chongchima, Chongchuckmyun, Jeokchima, Jeokchuckmyun). Shoot formation were observed from all cultivars on MS medium supplemented with 0.1 mg/L NAA and 0.5 mg/L BA. In all cultivars, when cotyledon was cultured, the number of shoot per explant was more greater than that hypocotyl and leaf disc were cultured. Shoot formation rate (91.7%) was high in a cotyledon culture of cultivar, Chongchukmyun. The growth of multiple shoots derived from the cultivar, Chongchukmyun, was most effective on medium containing 0.5 mg/L BA and 1.0 mg/L GA$_3$. When shoots were transferred on MS medium without plant growth regulators, roots were effectively differentiated. Rooted plantlets were acclimated on pots for further propagation.