• Journal of Plant Biotechnology
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• v.50
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• pp.163-168
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• 2023

Sweetpotato (Ipomoea batatas [L.]) is a globally important root crop cultivated for food and industrial processes. The crop is susceptible to the root-knot nematode (RKN) Meloidogyne incognita, a major plant-parasitic RKN that reduces the yield and quality of sweetpotato. Previous transcriptomic and proteomic analyses identified several genes that displayed differential expression patterns in susceptible and resistant cultivars in response to M. incognita infection. Among these, several sporamin genes were identified for RKN resilience. Sporamin is a storage protein primarily found in sweetpotato and morning glory (Ipomoea nil). In this study, transcriptional analysis was employed to investigate the role of sporamin genes in the defense response of sweetpotato against RKN infection in three susceptible and three resistant cultivars. Twenty-three sporamin genes were identified in sweetpotato and classified as group A or group B sporamin genes based on comparisons with characterized sweetpotato and Japanese morning glory sporamins. Two group A sporamin genes showed significantly elevated levels of expression in resistant but not in susceptible cultivars. These results suggest that the elevated expression of specific sporamin genes may play a crucial role in protecting sweetpotato roots from RKN infection.

• The Korean Journal of Mycology
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• v.47 no.4
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• pp.407-416
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• 2019

A common post-harvest disease of sweetpotato tuber is root rot caused by Fusarium solani in Korea as well as the other countries. Storage root rot disease was monitored earlier on sweetpotato (Ipomoea batatas) in storehouses of different locations in Korea. In the present study, an isolate SPL16124 was choosen and collected from Sweetpotato Research Lab., Bioenergy Crop Research Institute, NICS, Muan, Korea, and confirmed the identification as Fusarium solani by conidial and molecular phylogenetic analysis (internal transcribed spacer ITS and translation elongation factor EF 1-α gene sequences). The isolate was cultured on potato dextrose agar, and conidiation was induced. The fungus was screened for Fusarium root rot on tuber of 14 different varieties. Among the tested variety, Yenjami, Singeonmi, Daeyumi, and Sinjami showed resistant to root rot disease. Additionally, the pathogen was tested for pathogenicity on stalks of these varieties. No symptom was observed on the stalk, and it was confirmed that the disease is tissue specific.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.49-49
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• 2022

One of the major problems with sweetpotato (Ipomoea batats Lam.) is the tough thread tissue that occurs in the storage root, which has a negative impact on the sales of sweet potato because it impairs the texture during cooking and the processing quality. The fiber contents in storage roots of sweetpotato is affected by cultivation conditions and environment. To investigate the effect of fiber generation at different levels of irrigation, the sweetpoatoto "Hogammi" was transplanted in greenhouse. Sweetpotato was grown in styrofoam beds(W1605*D330*H300mm) to block moisture flowing from the outside. The irrigation was carried out as 3 levels (5,10, and 20 mm through drip irrigation facilities) at 20-day intervals. Five plants were harvested per plot at 90, 100 and 120 days after transplanting (DAT). The size of the storage root was large in the order of irrigation conditions 10mm>20mm>5mm treatment. And the longer cultivation period, the larger size of the storage root was observed. As a result of the analysis of the fiber content, it showed a tendency to decrease as the cultivation period increased (90days→120days). In addition, the fiber contents of sweetpotato harvested at 90, 100 and 120 DAT in the level of 5 mm irrigation plot were 351, 324 and 207 mg/100g, respectively, which were higher than those of other irrigation level plots. During all cultivation periods, the 10mm treatment group showed the lowest fiber content of 280, 228 and 127 mg/100g. At 20 mm irrigation level, the fiber content was less than that of 5mm irrigation level, but showed a tendency to increase compared to that of 10 mm irrigation level. These results suggested that drought stress or excessive-irrigation increases the fiber content of sweetpotato, which reduces their commercial value.

• Journal of Plant Biotechnology
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• v.36 no.3
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• pp.202-206
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• 2009

In many countries including China and U.S., researchers are developing methods to use sweetpotato as raw material for biofuel. We consider the sweetpotato is not only a source of green fuel, it eventually will provide various material including paper, adhesives, biodegradable plastics, and secondary metabolites. Sweetpotato is one of the high efficiency crop because it yields more calories per unit area than either maize or potato, and it requires the shortest growing cycle of the root crops grown in the tropics. Sweetpotato is the most useful crop for the coming starchbased industry era. Sweetpotato genetic resources are collected, characterized, evaluated, and maintained by U.S., China, Japan, and the International Potato Center. New varieties of sweetpotato using the proper genetic resources and molecular breeding will be developed to cope with the global food and energy in 21st century.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.1
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• pp.47-53
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• 2015

Storage root yield of sweetpotato was decreasing owing to continuous sweetpotato cropping, debasement of soil physical properties, increasing incidence of pest and disease. This study was conducted to evaluate the changes in physicochemical properties of the soil owing to subsoiling (subsoiling to 50 cm depth), and the effect on growth and yield of sweetpotato. The subsoiling treatments included subsoiling treated every year for two years, subsoiling in the first year, and no subsoiling control. The soil physical properties measured were bulk density, hardness, porosity, three phase. Bulk density, porosity, soild (%) of three phase were improved by subsoiling in topsoil and subsoil. Main vine length and vine yield in subsoiling soil were higher than those in no subsoiling soil, but those were not significantly different. Yield of marketable storage root in subsoiling soils treated every year for two years and treated in the first year was more increased 17% and 20% than no subsoiling soil, respectively. The number of marketable storage root per plant was also higher in subsoiling soils than no subsoiling soil, but it was not significantly different. Soluble solid contents and total free sugar contents of storage root of sweetpotato were not significantly different among the treatments. These results show that improving soil physical properties by subsoiling could promote high yield of marketable storage root in continuous sweetpotato cropping field.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.3
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• pp.262-270
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• 2012

This research was performed to find out the root characteristics of sweetpotato (Ipomoea batatas LAM.) cultivars according to the cultivation regions. Total 10 sweetpotato culivars, 6 yellow, 2 purple and 2 orange, were used for experiment. Samples were cultivated in Muan, Iksan, Nonsan, Boryeong and Hamyang. Precipitation and average temperature during the growth period of sweetpotato cultivation were 882~1,682 mm and 16.7~$28.2^{\circ}C$, respectively. Accumulated temperature was 3,122~$3,282^{\circ}C$. Soil texture was found of sandy loam in Muan, Iksan and Boryeong, sandy clay loam in Nonsan, and loam in Hamyang. The yield of root, dry matter content, starch value and soluble solids contents were high in Muan. The length/width ratio was high in Hamyang. The color values of sweetpotatoes were high in Nonsan. The protein content of sweetpotato powder was high in the Iksan, crude fat content and ash content were high in the Hamyang. The results of this study, we could see that root characteristics of sweetpotato in the same cultivars appeared differently depending on the cultivated regions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.48-48
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• 2022

In recent, a demand for sweetpotato cultivation technology to expand the cultivated area of field crops in paddy fields is increasing. This research was carried out to establish suitable varieties and cultivation techniques for mass production of sweetpotato for processing raw materials. For the selection of varieties suitable for cultivation in rice fields for each processing purpose, 12 varieties in 2018 (8 varieties for starch, 4 as dried, chips and beverages), and 6 varieties in 2019 (4 varieties for starch including 'Daeyumi'; chips, semi-dried 'Pungwonmi'; beverage and coloring 'Shinjami') were used. Sweetpotato stems were planted in mid-May and harvested after 120 days to investigate the yield. Results revealed that the yield of sweetpotato (2019) for starch production, varied with variety as 'Gogeonmi' 3,926 > 'Jinhongmi' 3,428 > 'Daeyumi' 2,873 > 'Singeonmi' 2,752 kg/10a. The starch content was 20.2% in 'Daeyumi', 18.2 in 'Gogeonmi', 21.2 in 'Singeonmi', and 20.6% in 'Jinghongmi'. The total amount of starch was higher in 'Daeyumi' (730 kg/10a) and 'Gogeonmi' (731 kg/lOa). The yield of chips and edible varieties 'Pungwonmi' was 4,688 kg/10a. The yield of 'Shinjami' of purple variety such as beverages and powder was 3,139 kg/10a. Aaa result of evaluation sweetpotato yield by waterlogging treatments on different growing stages in paddy fields, the yields of 'Daeyumi' and 'Jinhongmi' varieties treated with waterlogging at the storage root formation stage decreased by 11.8% and 11.7%, respectively, compared to the control. In the case of waterlogging treatment at storage root swelling stage, Both varieties showed the lowest yield reduction at 7.0% and 4.8%, respectively. Based on these results, stable production and substitution effect of processing raw materials can be expected by cultivating sweetpotato varieties suitable for paddy cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47
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• pp.124-134
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• 2002

The sweetpotato, Ipomoea batatas L. (Lam.), is one of the important summer upland crops in Korea and has been used as human food, industrial yaw material and vegetable. Sweetpotato has been consumed for human foods such as boiled, roasted, fried or salad etc. It should be developed for higher quality as a snack or health food, primarily through improving the eating and marketing qualities as well as nutritional value. Its quality after cooking or processing is a complex one combining the aroma, taste, texture and fiber content. The other important qualities for consumers are root shape, size, skin color, flesh color, insect and disease resistance, nutritional components and safety from phytoalexins(toxic stress metabolites) etc. Korean people generally prefer to red skin color, round or elliptic shape and dry texture, yellow flesh color of sweetpotato which is high in starch content including vitamins and nutrients. The almost factors of quality components of sweetpotato are genetically controlled by breeder, but postharvest handlings and marketing management for making high quality goods should be done thoroughly according to the quality evaluation criteria of sweetpotato from the moment of harvest until shipping them to the market by farmers and the other users. This paper describes current status and prospects of the quality evaluations and researches in sweetpotato roots in Korea.

• Plant Biotechnology Reports
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• v.3 no.1
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• pp.75-85
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• 2009

We report here a first evaluation of chilling-responsive gene regulation in the sweetpotato. The growth of sweetpotato plants was severely retarded at $12^{\circ}C$; the lengths of the leaf, petiole, and root were markedly reduced and microscopic observation revealed that the elongation growth of the epidermal cells in each of these organs was significantly reduced. We examined the transcriptional regulation of three sweetpotato expansin genes (IbEXP1, IbEXP2 and IbEXPL1) in response to various chilling temperatures (12, 16, 22, and $28^{\circ}C$). In the leaf and petiole, the highest transcript levels were those of IbEXP1 at $28^{\circ}C$, whereas IbEXPL1 transcript levels were highest in the root. IbEXP1 mRNA levels in the $12^{\circ}C-treated$ petiole showed a fluctuating pattern (transient decrease-recovery-stable decrease) for 48 h. In the leaf and petiole, IbEXP1 and IbEXPL1 exhibited a similar response to chilling in that their mRNA levels decreased at $22^{\circ}C$, increased at $16^{\circ}C$, and decreased dramatically at $12^{\circ}C$. In contrast, mRNA levels of IbEXP2 in the leaf fell gradually as the temperature fell from 28 to $12^{\circ}C$, while they remained unaltered in the petiole. In the root, mRNA levels of IbEXPL1 and IbEXP1 reached maximum levels at $16^{\circ}C$, and decreased significantly at $12^{\circ}C$. These data demonstrated that expression of these three expansin genes was ultimately down-regulated at $12^{\circ}C$; however, transcriptional regulation of each expansin gene exhibited its own distinctive pattern in response to various chilling temperatures.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.54-54
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• 2022

Recently, as one of the major problems in the quality of sweetpotato, occurrence of thin and long fibrous tissues in storage root acts as a negative factor when consumers eat sweetpotato. In this study, the fiber content was compared according to the cultivation period in storage roots of 'Sodammi' and 'Hopungmi', which were newly bred and developed, and in that of 'Hogammi', which contains a lot of fibrous tissues. To isolate of fiber from storage root, the Association Official Analytical Chemists (AOAC) method was applied for quantifying fiber present in storage root of sweetpotato. The fiber contents isolated by this method is calculated by converting the weight of the storage root. The fiber content was measured every 20 days from 60 to 120 days after planting. As a result of this study, the lowest amount of fiber was 'Hopungmi' (70~140 mg/100 g), and the highest amount of fiber was observed in 'Hogammi' (115~223 mg/100 g). 'Sodammi' showed an intermediate level (104~149 mg/100 g) between the fiber content of 'Hopungmi' and 'Hogammi'. The fiber contents of 'Hopungmi' was 39% lower than that of 'Hogammi'. As the increased cultivation periods, the fiber contents showed a tendency to decrease. In the future research, the length, thickness, and fiber contents will be investigated to compare the degree of taste inhibition.