This study investigated the antioxidant characteristics of sweet potato according to different plant parts and drying methods. The sweet potato plant parts were divided into root tubers, stems, stalks, leaves, and tips, and the drying methods were freeze-drying and hot air drying. Total polyphenol and flavonoid contents and radical scavenging activity of the sweet potato plant parts were significantly different depending on the plant parts and drying methods. The total polyphenol content of freeze-dried sweet potato leaves and tips were 52.76 and 46.19 mg chlorogenic acid equivalents/g sample, and the total flavonoid contents were 222.47 and 214.12 mg quercetin equivalents/g sample, respectively, and decreased with hot air drying. DPPH radical scavenging activity was higher in freeze-drying than hot air drying and was significantly different depending on the plant parts. The ABTS radical scavenging activity of freeze-dried sweet potato leaves and tips were 43.48 and 44.68 mg Trolox equivalents/g sample, respectively, and decreased with hot air drying. Therefore, additional studies on the functionality of using by-products from sweet potato cultivation are needed.

남부지역에서 고구마 바이러스 무병묘의 정식시기 및 재배 기간에 따른 괴근 수량 및 씨고구마 생산량을 조사한 결과는 다음과 같다. 1. 바이러스 무병묘 정식시기에 따라 씨고구마로 사용하기에 알맞은 100~300 g 크기의 괴근 생산량은 6월 중순 정식 재배에서 ‘신율미’ 2,364 kg/10a, ‘풍원미’ 2,625 kg/10a 수준이었다. 2. 바이러스 무병묘를 7월 상순에 정식하여 재배하여도 씨고구마로 사용하기에 알맞은 100~300 g 크기의 괴근 수량은 ‘신율미’ 2,043, ‘진홍미’ 1,799, ‘다호미’ 1,390, ‘풍원미’ 1,985 kg/10a 정도가 생산되었다. 3. 고구마 바이러스 무병묘 정식 후 110일, 120일, 그리고 130 일 재배 시 씨고구마 수량은 ‘풍원미’ 1,605, 1,907, 1,834 kg/ 10a, ‘호감미’ 1,816, 1,771, 2,137 kg/10a 수준으로 생산되었다. 4. 수확 전 채취한 고구마 잎에서 SPLCV, SPFMV, SPVG, SPLV 등 4종 바이러스 이병 정도를 검정한 결과 정식시기, 재배기간 등 품종에 따라 약간 차이는 있으나 낮게 검출되어 다음해 씨고구마 종자로 문제가 없다고 판단하였다. 5. 바이러스 무병묘 대량 증식에는 시설과 노력이 많이 소요되고 증식량이 적어 면적 확대에 어려움이 있기 때문에 무병씨고구마를 생산하면 면적 확대에 유리하다. 무병묘가 소량 일 경우는 계속 증식하면서 7월 상순까지 본밭에 정식하여도 씨고구마 생산이 가능하였다. 금후에는 무병묘로 생산한 연차 간 씨고구마에 대해 품종별 수량과 품질 평가 후 씨고구마의 적정 갱신 주기를 설정하고자 한다.

1. 본 연구는 고구마의 큐어링 처리 및 저장기간에 따른 품종별 저장성 차이를 조사하여 품종별 적정 저장 조건을 설정하고자 수행하였다. 수확된 고구마는 온도 32±1℃, 상대습도 92±3% 조건에서 3일간 큐어링 처리를 실시하였고 대조구와 함께 13±℃의 저장고에 30주간 저장하였다. 2. 저장 기간에 따른 부패율 및 감모율은 품종별로 큐어링 처리 여부에 따라 다른 양상을 보였으며 대부분 품종에서 큐어링 처리구의 부패율과 감모율이 낮게 나타났다. 품종별로는 ‘호감미’, ‘풍원미’, ‘신건미’, ‘주황미’가 장기저장을 위해서 큐어링 처리가 필요한 품종으로 나타났으며, ‘다호미’, ‘연자미’ 품종은 큐어링 처리 여부에 따른 유의한 차이가 없었다. 3. 큐어링 처리 여부에 따른 부패율 차이가 없었던 ‘다호미’, ‘연자미’를 제외한 나머지 품종은 감모율 조사에서도 큐어링 처리가 장기 저장에 더 유리한 것으로 조사되었다. 4. ‘호감미’ 품종의 경우 저장기간별 부패율 및 감모율을 예측하고 조수입을 계산하였을 때 큐어링 처리 시에는 조수입이 증가하였으나 큐어링 무처리 시에는 저장기간이 길어질수록 조수입이 감소하였다. 5. 따라서 이러한 품종별 저장성 차이를 고려하여 각 품종에 맞는 수확 후 관리 및 적정 출하시기를 예측하는 것이 고구마 저장성 증대 및 농가 소득 향상에 유용하게 적용될 수 있을 것으로 판단된다.

This study was carried out to obtain the basic quality characteristics, like moisture contents, hunter color value, total polyphenol, starch, amylose, and ash contents and pasting characteristics of sweet potato cultivars according to storage periods. Moisture contents of all the varieties decreased with long storage period, and were lower in dry type than tender and moist type sweet potato. Lightness(L value) of sweet potato flesh was decreased in Shinyulmi, Daeyumi, Shinhwangmi but other seven cultivars showed increasing trend. Redness(a value) was increased in Sinyulmi, Sinhwangmi, Sinjami and yellowness (b value) increased in Yeonjami only. The total polyphenol contents increased in Dahomi, Sinjami up to 4 months of storage and all other varieties showed decrease during storage period. The starch contents also decreased with storage period. The amylose contents showed different by the cultivars. The ash contents in all varieties ranged from 1.1 to 1.7%, and there was no difference among varieties and storage periods. There was no change in pasting temperature during storage periods. Peak viscosity, through viscosity, breakdown and final viscosity were different according to storage periods and cultivars. But setback tended to increase in all cultivars.

Sweet potato [Ipomoea batatas (L.) lam] plant is known to have the relatively tolerance soil moisture deficit compared to other upland crops. However, recently, it has been causing plant growth inhibition and decrease storage quality due to the drought during the growing season of sweetpotato in Korea. The response of root elongation, leaf and shoot growth of sweet potato plantlets, cultivated under different water potential conditions were observed. Six varieties, such as yellow fleshed (Jinhongmi), dark-yellow fleshed (Daeyumi), dark-orange fleshed (Juhwangmi), light-orange fleshed (Dahomi, Pungwonmi), and purple fleshed (Sinjami) were used in this experiment. Using the follow water osmotic potential (WOP) levels were 0 (control), -0.05, -0.1, -0.2, -0.3, -0.4, -0.5 MPa by polyethylene glycol (PEG). In in vitro culture condition, ‘Jinhongmi’ has been inhibited rooting number and number of leaves less than 2, although slightly low WOP of–0.05 and –0.1 MPa, and at –0.2 MPa. shoot was not growing. ‘Daeyumi’, Dahomi, and Juwhangmi’ produced 2 roots as a low WOP of –0.3 MPa. and at –0.2 MPa., it appeared 2 or 3 leaves. ‘Pungwonmi’ produced similar to root number 3.9 at –0.1 MPa compared to control, but root weight decreased 75% at - 0.1 MPa more than control. Root did not grow at – 0.2 MPa for ‘Sinjami’. In nursery bed culture condition, roots fresh weight, number of leaves, and shoot length were inhibited according to the decreases of water osmotic potential. In the case of leaf area, ‘Jinhongmi’ and ‘Daeyumi’ was a significantly difference to 8.4, 22.6 cm3 at –0.2 MPa compared to control, respectively. No difference were obsered for ‘Dahomi’ at -0.1 and –0.2 MPa. ‘Pungwonmi’ was decreased 86% at -0.1 MPa compared to the control. ‘Juhwangmi’ and ‘Sinjami’ was a significantly difference to 15.5, 3.6 cm3 at –0.1 MPa compared to control of 22.9, 16.8 cm3, respectively.

Spodoptera litura (Fabricius, 1775) is considered as a serious agricultural pest, which damaged to the many crops including sweet potato (Ipomoea batatas). We investigated weekly occurrence of the Spodoptera litura (Fabricius) using pheromone trap at six study fields of three regions, Jeonnam, Korea. A total of 41,895 individuals were collected from 18th July to 23th September in 2013; Yeongamgun was collected the highest individuals (17,519), and following the Muan-gun (12,709) and Haenamgun (11,667). The seasonal occurrence of S. Litura was increased from July to September, and peak occurrence timing was in late-September. There were a positive correlation between field area and number of individuals (P=0.02, r=0.89), and a negative correlation between field area and density (p=0.02, r=-0.89). As a PCA (principal component analysis) result, adults occurrence pattern were closely related to the temperature and relative humidity during larva stage.

The most common method of vegetative propagation of virus free plantlets is the use of shoots meristem culture in solid medium culture. This study was to investigate the effect on liquid medium culture for the growth of virus-free sweetpotato plantlets. Single-nodes derived from meristem culture of sweetpotato was examined in this experiment and three sweetpotato varieties ‘Singeonmi’, ‘Sinhwangmi’, and ‘Sinjami’ was used. The growth of plnatlets was greater in liquid medium culture than that of solid medium culture after longer incubation in 3 varieties. The total fresh weight of 5 week old plantlets after planting in solid culture were 2.17 g (‘Singeonmi’), 2.49 g (‘Sinhwangmi’), and 2.18 g (‘Sinjami’), but the fresh weight in liquid medium culture was 3.87, 3.88, and 3.35 g, respectively. Leaf number of ‘Singeonmi’ and ‘Sinjami’ plantlets after 5 weeks of liquid medium culture was 21.1 and 22.6, respectively and liquid medium culture showed 3 and 6.2 more leaf number than that of solid medium culture. Plant height of ‘Sinhwangmi’ and ‘Sinjami’ plantlets after 3 weeks of liquid medium culture was 4.1 cm and 3.4 cm, respectively, and liquid medium culture showed 1.1 cm longer stem length than solid medium. Overall, liquid medium culture of sweetpotato plantlets was more effective than solid medium in terms of leaf and stem growth.

The effect of transplanting and harvesting dates on growth, yield, and quality of sweetpotato varieties was studied. Three sweetpotato varieties, Yulmi, Singeonmi, and Dahomi, were transplanted on 23 Apr., 21 May, 5 June, 15 June, 25 June, 5 July, 15 July, and 25 July. Fresh vine weight and marketable storage root yield of the three varieties were the highest in transplanting plots on 23 April and 21 May, respectively, and those tended to decrease when transplanting dates were late after May. GDD (Growing Degree Days) and cumulative radiation seemed to be related to marketable storage root yield. Number of marketable storage root per plant, average weight of marketable storage root, and marketable storage root yield were significantly different according to transplanting dates. Marketable storage root yield showed significantly positive correlations with fresh vine weight, number of marketable storage roots, and average weight of marketable storage roots. Hardness and dry matter content of storage root showed significantly positive correlations with starch content and decreased with late transplanting dates in Yulmi and Singeonmi varieties. Pasting temperature showed significantly positive correlations with soluble solid content, dry matter content, and amylose content, but it showed significantly negative correlations with breakdown. Setback was significantly different among varieties, but it was not significantly different in transplanting dates.

수확과정에서 버려지고 있는 고구마 잎을 이용한 기능성 식품소재로서 활용가능성을 검토하고자, 밀가루 중량 대비 고구마 잎 분말을 2, 3, 5, 7%의 비율로 첨가하여 식빵을 제조 하고, 반죽 및 제빵 특성, 생리활성 및 기능성분 등을 조사하 였다. 반죽의 수분흡수량은 7% 첨가 시 가장 높았고, 반죽시 간은 유의적인 차이를 보이지 않았으며, 반죽의 저항도는 2~3% 첨가할 때가 가장 안정적이었다. 식빵의 수분 함량은 첨가량이 증가하여도 큰 차이를 보이지 않았고, 식빵의 내부색은 첨가량이 증가할수록 L값과 a값은 감소하였으나, b값은 증가하였다. 식빵의 부피와 비용적 및 굽기 손실률은 첨가량 이 증가할수록 감소하였으나, 항산화 활성과 총 폴리페놀, 루 테인 및 베타카로틴 함량은 증가하였다. 관능평가의 결과, 고 구마 잎 분말의 2~3% 첨가 시 맛과 색깔, 조직감, 입안에서의 씹힘성과 종합적인 기호도에서 가장 우수한 값을 얻었다. 이 상의 결과에서 고구마 잎 분말의 2~3% 첨가 시, 제빵 적성과 기능성, 상품성이 우수한 식빵을 제조할 수 있었다.

본 연구에서는 2년간 수원 밭작물 시험포장에서 단옥수수 품종인 고당옥과 구슬옥을 파종시기에 따른 생육 및 이삭 특성을 검토한 결과이다. 1. 고당옥과 구슬옥 모두 파종시기가 늦어질수록 파종에서 출사기까지의 일수가 짧아졌고, 출사에서 수확기간은 증가하였다. 2011년의 출사일수는 43 ~ 53일, 2012년은 44 ~ 54일이었고, 출사에서 수확까지는 2011년은 22 ~ 36일, 2012년에는 20 ~ 34일이었다. 2. 파종에서 출사기까지 생장온도일수(GDD)는 출사 후부터 수확기까지는 약 213 ~ 353oC 범위로 비슷하였으나 파종에서 수확까지의 GDD는 2011년(약 916 ~ 1,067oC)과 2012년(약 911 ~ 1,055oC) 모두 큰 차이가 없었다. 특히 8월 5일 파종에서 등숙기 중의 생장온도일수가 다른 파종시기에 비하여 크게 낮았는데 이는 등숙기의 기온이 상대적으로 낮은 것이 원인으로 판단된다. 3. 파종시기에 따른 생육특성을 보면 간장과 착수고는 파종시기가 늦어질수록 짧아졌으며 7월 말 파종 재배에서 유의하게 짧았으며, 경태는 파종시기가 늦어질수록 유의하게 얇아지는 경향을 보였다. 이삭직경은 고당옥은 4.37mm, 구슬옥은 4.43mm로 차이가 없으나 6월, 8월 파종보다 7월 파종구에서 두꺼운 것으로 나타났다. 4. 이삭무게는 두 품종 모두 6월, 8월 파종구 보다 7월 파종구에서 높고, 7월 25일 파종구를 보면 고당옥은 201g, 구슬옥은 140g으로 높았다. 2년간 단위면적당 이삭수량은 고당옥은 715kg/10a이고, 구슬옥은 677kg/10a이었다. 5. 파종시기에 따른 단옥수수 재배는 파종기가 늦을수록 생육이 지연되고 이삭수량이 감소되는 경향이 있고, 단옥수수 만식재배에 따른 최적 파종시기는 7월 20일 ~ 25일로서, 두 품종 모두 7월 25일에 이삭 수량성이 높은 것으로 나타났다. 7월 20 ~ 25일 파종 시 생육이 지연되고 이삭수량이 감소되는 단점 이 있지만 6월 말에 재배한 단옥수수 보다 습해의 피해가 적고, 수확적기가 짧고 전분축적 시간의 지연으로 수확시기를 연장할 수 있다는 장점이 될 수 있을 것으로 판단되어진다. 따라서 추후 단옥수수 만식재배 시 수량과 상품성 향상을 위한 최적 수확적기, 저장방법에 대한 연구가 이루어져야 할 것이다.

‘Pungwonmi’, a new sweetpotato variety, was developed for table use by Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), RDA in 2014. This variety was derived from the cross between ‘Benisatsuma’ and ‘Luby3074’ in 2006. The seedling and line selections were performed from 2007 to 2009, and preliminary and advanced yield trials were carried out from 2010 to 2011. The regional yield trials were conducted at five locations from 2012 to 2014, and it was named as ‘Pungwonmi’. This variety has cordate leaf shape, and its leaves, stems, nodes, and petioles are green. Storage root of ‘Pungwonmi’ has an elliptical shape, red skin, and light orange flesh. ‘Pungwonmi’ was moderately resistant to fusarium wilt, and resistant to root-knot nematode. Dry matter content was 31.2%, and texture of steamed storage root was intermediate. Total sugar content of raw and steamed storage roots of ‘Pungwonmi’ was higher than that of ‘Yulmi’. β-carotene content of ‘Pungwonmi’ was 9.1 mg/100g DW. Yield of marketable storage root over 50 g of ‘Pungwonmi’ was 24.3 MT/ha under the early season culture, which was 46% higher than that of ‘Yulmi’. The number of marketable storage roots per plant was 2.8 and the average weight of marketable storage root was 156 g under the optimal and late season culture. Marketable storage root yield of ‘Pungwonmi’ was 24.1 MT/ha under the optimum and late season culture, which was 26% higher than that of ‘Yulmi’. (Registration No. 6428).

To obtain basic data on the effects of differences cultivation periods and methods on growth and development of sweet potato tuber. We investigated growth and development of six major cultivars showing different characteristics, such as dry type(Yulmi, YM; Jinhongmi, JHM), intermediate type(Pungwonmi, PWM; Hogammi, HGM), and purple type(Sinjami, SJM; Danjami, DJM). The average tuber weight of YM and JHM was 4.1 and 8.6 g respectively, 50 days after transplant. At 80 days, the weight of YM and JHM rapidly increased to 25.2 and 26.1 g, respectively. Finally, at 120 days, the weight of YM and JHM increased to 120.7 and 79.4 g, respectively. The average tuber weight of PWM and HGM was 13 and 3.3 g, respectively, 50 days after transplant. The development pattern of PWM showed a consistent increase in tuber weight during the cultivation period, an average weight of 104.2 g at 120 days. However, the tuber development pattern of HGM was different from that of PWM. The average tuber weight of HGM rapidly increased for 100 days after transplant and then showed no increase at 120 days. In case of purple type sweet potato, the average tuber weight of SJM consistently increased during the cultivation period, whereas DJM showed rapid increase in average tuber weight at 80 days after transplant. Korean consumers prefer small, round sweet potato approximately 100g in weight. Based on the results, YM, PWM and SJM are classified as early developing cultivars that can be harvested approximately 120 days after transplant. On the other hand, JHM, HGM, and DJM are classified as late developing cultivars that can be harvested approximately 130 days after transplant.

‘Geonhwangmi’, a new sweetpotato variety, was developed for table use by Bioenergy Crop Research Institute, National Institute of Crop Science (NICS), and RDA in 2013. This variety was derived from the cross between ‘Singeonmi’ and ‘Mokpo34’ in 2005. The seedling and line selections were performed from 2006 to 2008, preliminary and advanced yield trials were carried out from 2009 to 2010. The regional yield trials were conducted at five locations from 2011 to 2013, and it was named as ‘Geonhwangmi’. This variety has five-lobed leaf, and its leaves, stems, and petioles are green. Storage root of ‘Geonhwangmi’ has an elliptical shape, red skin, and light orange flesh. ‘Geonhwangmi’ was moderately resistant to fusarium wilt, and resistant to root-knot nematode. Dry matter content was 29.4%, and texture of steamed storage root was intermediate. Sucrose content of steamed storage root of ‘Geonhwangmi’ was higher than that of ‘Yulmi’, and steamed storage root palatability of ‘Geonhwangmi’ was better than that of ‘Yulmi’. β-carotene content of ‘Geonhwangmi’ was 3.4 mg/100g DW, which was 7.8% of ‘Juhwangmi’. Yield of marketable storage root over 50 g of ‘Geonhwangmi’ was 23.0 MT/ha under the early seasonal cultivation, which was 39% higher than that of ‘Yulmi’. The number of marketable storage roots per plant was 2.6 and the average weight of marketable storage root was 151 g under the optimal and late seasonal cultivation. Marketable storage root yield of ‘Geonhwangmi’ was 24.2 MT/ha under the optimum and late seasonal cultivation, which was 45% higher than that of ‘Yulmi’. (Registration No. 5853).

‘다호미’는 국립식량과학원 바이오에너지작물연구소에서 2012년에 육성한 식용 고구마 품종으로 2005년에 ‘무안4호’를 모본으로, ‘진홍미’를 부본으로 하여 인공교배 하였다. 2007년부터 2008년까지 계통선발시험과 2009년부터 2010년까지 생산력검정시험을 실시하여 괴근 수량성, 상품성, 식미가 우수한 MI2005-05-04 계통을 ‘목포80호’로 계통명을 부여하였다. 2011년부터 2012년까지 2년간 지역적응시험을 수행한 결과, 괴근의 수량성, 상품성이 우수하고 식미가 양호하여 2012년 12월 농촌진흥청 농작물직무육성신품종선정심의회에서 신품종으로 선정되어 ‘다호미’라 명명하였다. ‘다호미’는 잎의 결각이 3개 내지 5개이고, 결각의 깊이는 보통이며 엽색, 잎자루색, 줄기색은 녹색이다. 괴근의 껍질색은 홍색, 육색은 담주황색이며 괴근 모양이 방추형으로 균일하여 상품성이 우수하다. ‘다호미’는 덩굴쪼김병에 강한 편이나 뿌리혹선충에는 저항성이 없다. ‘다호미’는 육질이 중간질이고 전분가는 20.9%으로 낮은 편이며 당도는 24.8 Brix°이고 총유리당은 생고구마가 9.7, 찐고구마가 32.0 g/100g (D.W.)으로 ‘율미’보다 높다. ‘다호미’는 조기재배시 상품괴근수량이 26.3 MT/ha으로 ‘율미’의 17.3 MT/ha보다 52% 증수되었다. 적기 및 만기재배시 상품괴근수량은 21.9 MT/ha으로 ‘율미’보다 35% 증수되었으며 주당상품괴근수는 2.8개/주, 상품괴근평균중은 138 g이다.

To analysis of virus free sweetpotato effect, 5 virus free sweetpotato and virus normal sweetpotato varieties were planted in 5 different regions at 2010 year. The average yields of virus free sweetpotato are showed different results according to regions. Sinjami which cultivated at Iksan were increased maximum 68% compare to normal. However, Sinjami which cultivated in Hamyang were decreased yield 11% compare to normal. Analysis of tuber formation ratio of Sinjami, Yenhwangmi, Singeonmi which cultivated in Nonsan were decreased tuber number compare to normal. However, 3 varieties were all increased on Average storage root weight and yield of marketable storage root. In the results of analysis of marketable storage root according to cultivated regions and varieties, all varieties except Sinjami which cultivated in Hamyang were increased yield. Also, quality of virus free sweetpotato were enhanced 7 to 9 compare to virus infected sweet potato which showing average 3. Contents of starch between virus free and virus infected sweetpotato were not affected by virus. Virus free sweetpotato were more increased starch products according to increased total production yield. Also, Brix° (%) was not showing difference between virus free and virus infected sweetpotatoes. In this experiment, Virus free sweetpotato are enhanced production yields and quality. Therefore, we suggested that virus free sweetpotato is one of the methods to reduce damage by sweetpotato virus.

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.