• Journal of Plant Biotechnology
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• v.3 no.2
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• pp.59-66
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• 2001

Photoautotrophic micropropagation systems do not include sugar in the culture media. This characteristic provides advantages to scale up the micropropagation systems comparing photomixotrophic micropropagation systems. A closed, large-scale photoautotrophic micro-propagation for transplant production system has been developed at Chiba University, Japan. New concepts and technologies were adapted to produce high quality transplants at minimum usage of resources, and as scheduled. Newly developed software for production management was used to enhance the efficiency of the transplant production system. Currently, virus-free transplants of sweetpotato (Ipomoea batatas (L.) Lam.) are vegetatively propagated and produced under sterilized conditions in this system. This system can also be used for production of transplants of any other species including horticultural and woody plants with a minimum of modification.

• Journal of Plant Biotechnology
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• v.29 no.3
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• pp.189-192
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• 2002

An efficient plant regeneration system of major cultivars of sweetpotato (Ipomoea batatas (L.) Lam.) in Korea via somatic embryogenesis was established. Embryogenic calli were formed from shoot apical meristems of sweetpotato cultivars when cultured on LS medium supplemented with 1 mg/L auxin (2,4-D, picloram, dicamba). Among three kinds of auxin, 1 mg/L 2,4-D showed the highest embryogenic calli induction rate. After 4 weeks of cultures on LS medium supplemented with 1 mg/L 2,4-D, embryogenic calli induction rates of Sinhwangmi, Zami, Yulmi, and White Star were 86%, 78%, 76%, and 80%, respectively. Upon transfer onto LS basal medium, most of somatic embryos developed into plantlets. Regenerated plantlets were transplanted to potting soil and grown to mature plants in a greenhouse.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.219-223
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• 2009

Oxidative stress derived from excess reactive oxygen species (ROS) is a major damaging factor for plants exposed to environmental stresses. Sweetpotato [Ipomoea batatas (L.) Lam] has a relatively broad adaptability to harsh environmental conditions compared to other staple crops. In this study, to select stress-tolerant sweetpotato cultivars for sources of molecular breeding on marginal lands, we evaluated the ion leakage values in 10 different cultivars after treatment of methyl viologen (MV), an ROS-generating nonselective herbicide, to leaf discs. DPPH radical scavenging activity and the contents of total phenolics were also investigated. The ion leakage of each cultivar showed a diverse value, which is well correlated with DPPH radical scavenging activity of each cultivar. DPPH radical scavenging activity also showed a high corelation with the contents of total phenolic contents. Three cultivars of Yanshu 8, Shinhwangmi and Shinzami showed high antioxidant activity. Our results suggest that a simple and efficient DPPH radical scavenging activity would be a suitable method to select potential cultivars with enhanced tolerance to multiple environmental stress.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.197-201
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• 2009

The food self-support rate on the basis of cereals in Korea is approximately 27%, which will threaten the national food security. The dramatic increase in population accompanied by rapid industrialization in developing countries has caused imbalances in the supply of food and energy. To cope with these global crises over food and energy supplies as well as environmental problems, it is urgently required to develop new environmentally friendly industrial crop varieties to be grown on marginal lands including desertification areas for sustainable development. Sweetpotato (Ipomoea batatas (L.) Lam.) ranks seventh in annual production among food crops in the world. Its wide adaptability on marginal lands and rich nutritional content provide a high potential for preventing malnutrition and enhancing food security in the developing countries. In addition, sweetpotato can be developed as a bioreactor to produce valuable industrial materials including bio-ethanol, functional feed and antioxidants by molecular breeding. In this respect, we focus on the molecular breeding of sweetpotato with multi-function on marginal lands. The strategies for development of environmentally friendly industrial sweetpotato will be introduced and discussed.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.207-213
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• 2009

Starch serves not only as an energy source for plants, animals, and humans but also as an environmentally friendly alternative for fossil fuels. Progress in understanding of starch biosynthesis, and the isolation of many genes involved in this process have enabled the genetic modification of crops in a rational manner to produce novel starches with improved functionality. Starch is composed of two glucose polymers, amylose and amylopectin. The amylose and amylopectin ratio in starch affects its physical and physicochemical properties. Alteration in starch structure can be achieved by modifying genes encoding the enzymes responsible for starch biosynthesis and starch hydrolysis. Here, we describe recent findings concerning the starch modification in sweetpotato. Sweetpotato [Ipomoea batatas (L.) Lam] ranks seventh in annual production among food crops in the world as an important starch source. To develop transgenic sweetpotato plants with modifying starch composition, we constructed transformation vectors overexpressing granule bound starch synthase I and inhibiting amylopectin synthesis genes such as starch branching enzyme and isoamylase under the control of 35S promoter, respectively. Transformation of sweetpotato (cv. Yulmi) is in progress.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.214-218
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• 2009

Sweetpotato [Ipomoea batatas (L.) Lam] leaves are excellent source of low molecular weight antioxidants such as polyphenols, anthocyanins and carotenoids compared to other leafy vegetables. Endogenous antioxidants in sweetpotato help our bodies to prevent ageing, heart diseases and cancer. In this study, to develop the proper cultivars for the functional feed materials, we investigated the contents of anthocyanin, $\beta$-carotene, and polyphenols as well as DPPH radical scavenging activity in leaves of 14 different cultivars at the time of the harvest. They showed a diverse antioxidation activity. In DPPH radical scavenging activity, cultivars of Nanjing 9, Yulmi and Shinzami showed higher activity, whereas cv. Huiza 6 showed the lowest. Cultivars of Shinzami and Shinhwangmi had the highest anthocyanin (3.5 mg/g fr wt) and polyphenol (15.8 mg/g fr wt) content, respectively. Interestingly, there was a high correlation between cultivars with colorful pigments in storage roots and antioxidants activity in leaves. These results suggest that sweetpotato leaves with high antioxidant activity at harvest would be suitable for functional feed materials.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.2
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• pp.123-132
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• 2024

In this study, two types of biodegradable film prototypes were produced using plastic resin containing rice powder. The application of these biodegradable films in sweetpotato (Ipomoea batatas L. Lam) fields and their impacts of plant growth, yield, and the soil environment were assessed, in comparison with Polyethylene (PE) film. The light transmittance of the biodegradable film containing 30% of 350 mesh rice powder (BF30-350RP) was 0.8%, which was lower than the 2.0% light transmittance of the biodegradable film containing 40% of 500 mesh rice powder (BF40-500RP) and 2.7% light transmittance of PE film. Surface temperature measurements on clear day indicated that the PE film exhibited the lowest temperature, with the minimal difference observed between BF40-500RP and BF30-350RP. Assessment of the damage ratio resulting from agricultural work revealed a ranking of 0.4% for the PE film, 3.3% for BF500-400RP, and 5.3% for BF350-30RP. Visible decomposition of BF40-500RP and BF30-350RP commenced after 40 and 30 days of outdoor exposure, reaching 62.3% and 70.4% decomposition at 90 days post-exposure, respectively. The decomposition of biodegradable films applied to sweetpotato fields progressed more slowly in BF40-500RP than in BF30-350RP. The BF40-500RP film on the surface of the ridges was decomposed by 5%, 30%, 55%, and 90% after 30, 60, 90, and 120 days after planting sweetpotato cuttings, respectively. Both types of biodegradable films at the ridge and furrow borders were completely decomposed after 75 days of sweetpotato planting. In a field where the surface was sealed by mulching without growing sweetpotatoes, the soil moisture and its deviation were lower in the order of PE film, BF40-500RP, and BF30-350RP, but the differences were not significant. The soil temperature was higher for PE film mulching than for the biodegradable films containing rice powder, but the differences were small. Two months after sweetpotato planting, the daily average soil moisture decreased by 2.5%point for BF30-350RP mulching, 1.5%point for BF40-500RP mulching, and 1.1%point for PE film mulching over seven days. Soil temperature was similar for both biodegradable film mulches, but increased steadily for the PE film mulch, reaching a daily average of 0.1℃ higher than for the biodegradable films. Sweetpotato vine growth and tuber yield were similar for all the mulching films tested.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.682-692
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• 2013

We investigated out the effect of cultivation region on the physicochemical characteristics of starch in six sweetpotato cultivars. The following sweetpotato cultivars were analyzed: Daeyumi, Shingeonmi, Jinhongmi, Shinyulmi, Yulmi, and Yeonhwangmi. Samples were cultivated in Muan, Iksan, Nonsan, Boryeong and Hamyang. The soil texture was found to be sandy loam in Muan, Iksan, and Boryeong, sandy clay loam in Nonsan, and loam in Hamyang. The starch content of the sweetpotato was higher in Muan than in Hamyang. The amylose content was 22.3-30.9%, and the highest amylose content was found in samples from Iksan. Rapid viscosity analysis showed that the samples from Hamyang had the lowest values of pasting temperature, while samples of the Daeyumi cultivar had the highest values. Thermal analysis with a differential scanning calorimeter showed that the Muan samples had the highest values of onset temperature, maximum peak temperature, and completion temperature, and the samples from Hamyang had the lowest values. There was no difference between the cultivation regions or the cultivar in the X-ray pattern of the starch or its appearance in scanning electron micrographs. Therefore, the results of this study confirm that cultivation region and cultivar play an important role in determining the quality of sweetpotato and the physicochemical characteristics of sweetpotato starch.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.190-195
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• 2018

Sweetpotato [Ipomoea batatas (L.) Lam] represents an attractive starch crop that can be used to facilitate solving global food and environmental problems in the $21^{st}$ century. It can be used as industrial bioreactors to produce various high value-added materials, including bio-ethanol, functional feed, antioxidants, as well as food resources. The non-profit Center for Science in the Public Interest (CSPI) announced sweetpotato as one of the ten 'super foods' for better health, since it contains high levels of low molecular weight antioxidants such as vitamin-C, vitamin-E and carotenoids, as well as dietary fiber and potassium. The United States Department of Agriculture (USDA) also reported that sweetpotato is the best bioenergy crop among starch crops on marginal lands, that does not affect food security. The Food and Agriculture Organization (FAO) estimated that world population in 2050 will be 9.7 billion, and require approximately 1.7 times more food than today. In this respect, sweetpotato will be a solution to solving problems such as food, energy, health, and environment facing the globe in the $21^{st}$ century. In this paper, the current status of resources, and cultivation of sweetpotato in the world was first described. Development of a new northern route of the sweetpotato and its prior tasks of large scale cultivation of sweetpotato, were also described in terms of global food security, and production of high-value added biomaterials.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.196-206
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• 2018

Dramatic increase in global population accompanied by rapid industrialization in developing countries has led to serious environmental, food, energy, and health problems. The Food and Agriculture Organization of the United Nations has estimated world population will increase to 9.7 billion by 2050 and require approximately 1.7 times more food, and more than 3.5 times energy than that of today. Particularly, sweetpotato is easy to cultivate in unfavorable conditions such as heat, drought, high salt, and marginal lands. In this respect, sweetpotato is an industrially valuable starch crop. To replace crops associated with these food and energy problems, it is necessary to develop new crops with improved nutrients and productivity, that can be grown on marginal lands, including desertification areas using plant biotechnology. For this purpose, exploring useful genes and developing genetically modified crops are essential strategies. Currently, sweetpotato [Ipomoea batatas (L.) Lam.] have been re-evaluated as the best health food and industrial crop that produces starch and low molecular weight antioxidants, such as vitamin A, vitamin E, anthocyanins and carotenoids. This review will focus on the current status of research on sweetpotato biotechnology on omics including genome sequencing, transcriptome, proteomics and molecular breeding. In addition, prospects on molecular breeding of sweetpotato on marginal lands for sustainable development were described.