식물병연구 Note Open Access Res. Plant Dis. 23(1): (2017) 충북에서사과주요토양병에의한고사율과재배환경과의상관관계 Correlation between t

식물병연구 Note Open Access Res. Plant Dis. 23(1): 49-55 (2017) https://doi.org/10.5423/rpd.2017.23.1.49 충북에서사과주요토양병에의한고사율과재배환경과의상관관계 Correlation between the Dieback Ratio and Cultivation Environment for Apple Orchards Infected by Soil-Borne Diseases in Chungbuk Province 이성희 1 ㆍ권의석 1 ㆍ신현만 1 ㆍ김익제 1 ㆍ남상영 1 ㆍ홍의연 1 ㆍ김대일 2 ㆍ차재순 2 * 1 충청북도농업기술원연구개발국, 2 충북대학교농업생명환경대학 *Corresponding author Tel: +82-43-261-2554 Fax: +82-43-271-4414 E-mail: jscha@cbnu.ac.kr Sung-Hee Lee 1, Yeuseok Kwon 1, Hyunman Shin 1, Ik-Jei Kim 1, Sang-Young Nam 1, Eui Yon Hong 1, Daeil Kim 2, and Jae-Soon Cha 2 * 1 Bureau of Research & Development, Chungcheongbuk-do Agricultural Research & Extension Services, Cheongju 28130, Korea 2 College of Agriculture, Life & Environment Sciences, Chungbuk National University, Cheongju 28644, Korea Received October 17, 2016 Revised December 11, 2016 Accepted January 6, 2017 The previous study showed that die-back of apple trees caused by soil-borne diseases was significantly high in the apple orchards in Chungbuk province. The correlation between dieback ratio and cultivation environment in apple orchards infected by soil-borne diseases was investigated in this study. The dieback ratio of five orchards diseased by violet root rot and five places infected by white root rot showed significantly positive correlation with Ca content and available P 2 O 5 content in soil, respectively. Whereas, the dieback ratio of fourteen orchards diseased by Phytophthora root rot was not significant. Subgrouping of cultivation environment analysis showed that the slope degree of orchard and the number of fruit setting also affected the dieback ratio caused by violet root rot and Ca content in soil also affected the dieback ratio caused by white root rot. It showed that the slope degree, soil texture, Mg and Ca content affected the dieback ratio caused by Phytophthora root rot. These results can be applied to reduce die-back ratio by the modification cultivation environment for each soil-borne disease. Keywords: Apple tree, Cultivation environment, Dieback, Root rot, Soil-borne diseases 최근충북에서사과자주 흰날개무늬병, 역병등토양 병에의한반복적인사과나무고사로재배농가의경제적 인손실이심각한수준이다 (Lee 등, 2016). 이들토양병원균 에감염되면잎의조기황화와낙엽이되고과일비대도정 지한다. 또한이듬해엽수가줄어들고신초및결과지생장 이불량해지는등빈가지수가증가하여착과를기대하기 Research in Plant Disease pissn 1598-2262, eissn 2233-9191 www.online-rpd.org 어렵다. 이러한지상부의증상은생리장애와혼동하기쉬워그원인을빠르고정확하게알아내기는어렵다 (Lee 등, 1995). 또한병이많이진전이되어병징이뚜렷해질시기에는근권부의부패가심하여방제시기를놓치게되고결국고사하게된다 (Lee 등, 2009). 더욱이이병된뿌리를완전히제거하지못하기때문에토양내수분및설치류를통한병확산으로해당사과원에서는방제에커다란어려움을겪고있는실정이다. 우리나라의사과원에서사과나무토양병에의한고사 The Korean Society of Plant Pathology cc This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 49

50 Research in Plant Disease Vol. 23 No. 1 와재배환경과의상관관계에대한연구는매우드물다. Lee (1995) 는전국사과주산지를중심으로사과자주 흰날개무늬병에대한발생생태를보고하였고, Lee (2002) 는사과흰날개무늬병에대한발생생태를보고한바있으며, Lee 등 (2016) 은기후온난화와논재배면적증가등의영향으로사과역병증가를보고하였으나여전히발생생태에대한연구는미미한실정이다. 따라서, 본연구는충북에서사과토양병 ( 사과자주 흰날개무늬병및역병 ) 에의한고사실태연구 (Lee 등, 2016) 를바탕으로고사율과피해사과원의재배방법, 재배환경및토양물리 화학성과의상관관계를파악하고자하였다. 2013년부터 2015년까지충북청주, 충주, 제천, 영동, 진천, 괴산, 음성등도내 7개시 군에서토양병에의해필지당사과나무가 10주이상고사한사과원 24개소를분석하였다. 식재주수, 수령, 재식거리, 품종및대목종류, 평균착과량, 발병최초연도, 과원방향, 재식방향, 암거설치여부, 지목상논인지밭인지등의재배환경조사는농가와문답식으로수행하였다. 대목종류는자근과이중대목구분없이 M.9과 M.26로나누었고과원방향은육안상평지와각방향별로구분하였다. 재식방향은동서와남북방향으로나누었다. 사과원의고도는 Altitude application (version 2.06a9; PyGDroid) 을이용하였으며, 경사도는육안상평탄지 (3% 미만 ), 완경사 (3% 10%) 및급경사 (10% 이상 ) 로 Lee 등 (1995) 의방법으로조사하였다. 피해사과원의토양물리 화학성은농촌진흥청토양화학분석법 (NAAS, 2010) 과토양및식물체분석법 (NIAST, 2000) 에준하여분석된흙토람 (http://soil.rda. go.kr) 의자료를활용하였다. 토양물리성중표토는사양토, 양토, 미사질양토로, 심토는식양질과사양질로, 유효토심은얕음, 보통, 깊음으로구분하였다. 또한배수는암거설치유무로, 지목은논 ( 객토포함 ) 과밭 ( 임야포함 ) 으로나누었다. 토양화학성은 ph, 유기물함량, 유효인산, 치환성양이온인칼륨, 칼슘, 마그네슘을포함시켰다. 통계처리는각각의토양병에의한사과나무고사율과피해사과원의재배환경및토양화학성과의상관관계는 Microsoft Exel 2010 프로그램 (Microsoft, Redmond, WA, USA) 을이용하여유의성 5% 수준에서상관및회귀분석으로수행하였다. Lee 등 (2016) 에의하면, 충북에서발생한토양병에의해사과나무가고사한피해과원은 7개지역의피해사과원 24개소에서총 26,765주가식재되어있었고고사주수는 3,350주로전체고사율은 11.5% 였다. 자주날개무늬병에의한피해사과원은 5개소에서 1,085주가고사하여고사율 3.7%, 흰날개무늬병에의한피해사과원은 5 개소에서 250 주가고사하여고사율 0.9% 였으며, 역병에의한피해사과 원은 14 개소에서 2,015 주가고사하여고사율이 6.9% 였다. 각토양병에의해피해를입은사과원의재배방법과환 경그리고토양물리 화학성을조사하여각토양병에의한 사과나무고사율과의상관관계를분석하였다. 그결과, 각 각의토양병에의한고사율과피해사과원재배환경과의 상관관계는 Table 1 과같았다. 자주날개무늬병피해사과원 5 개소는토양내칼슘함량과유의성있게정의상관관계를 보였고흰날개무늬병피해사과원 5 개소는토양내유효인 산함량과유의하게정의상관관계를보였다. 반면에역병 피해사과원 14 개소는유의성이없었다. 자주날개무늬병에의한고사율과피해사과원재배환경 을세분화한상관관계는 Table 2 와같았다. 비록표본수가 5 개로적었으나, 사과나무대목 M.9 을사용한사과원에서 는고사율과과원경사도가유의하게정의상관관계를보 였다. 심토가식양토인곳에서는고사율과착과수및토양 내칼슘함량이유의성있게정의상관관계를보였다. 또한, 암거배수관을설치한사과원및지목상밭인곳에서는모 두고사율과토양내칼슘함량이유의하게정의상관관계 를보였다. 그러나사과원이남향인곳과유효토심이보통 인곳에서는고사율과의상관성은없었다. Lee (1995) 의보 Table 1. Correlation coefficients between the dieback ratio and the cultivation properties in the apple orchards infected by each soil-borne disease (n=24) The dieback ratio by each soil-borne disease Violet root rot (n=5) White root rot (n=5) Phytophthora root rot (n=14) Tree age 0.203 0.526 0.063 No. of planting trees 0.424 0.547 0.345 Altitude 0.674 0.701 0.029 Slope degree 0.014 0.418 0.207 No. of fruit setting 0.472 0.807 0.150 ph 0.040 0.262 0.135 O.M. 0.794 0.230 0.186 Av. P 2 O 5 0.399 0.901* 0.116 K 0.516 0.525 0.160 Ca 0.924* 0.184 0.278 Mg 0.266 0.394 0.086 *P<0.05.

Research in Plant Disease Vol. 23 No. 1 51 고처럼왜화도가높은대목사용, 야산구릉지인과원, 식양토및수직배수가불량한과원에서자주날개무늬병의발병률이높다는것과유사하였다. 이렇듯왜화도가높은 M.9 대목사용에서경사도가심한곳과심토가식양토인곳에 서착과수증가는수세저하를야기하므로고사율이높았을것이라생각한다. 토양내칼슘은 Aphanomyces euteiches Drechsler에서난포자형성유도및난포자수를조절하는데중요한역할을하고 (Yokosawa 등, 1995), Pythium species Table 2. Correlation coefficients between the dieback ratio and the cultivation properties under subgrouping in the apple orchards infected by violet root rot (n=5) The dieback ratio by violet root rot Root stock M.9 (n=3) South direction of slope (n=3) Clay loam of subsoil texture (n=3) Underdrain Normally effective soil depth Upland on land category (n=5) Tree age 0.905 0.142 0.183 0.392 0.024 0.203 No. of planting trees 0.473 0.787 0.733 0.301 0.503 0.424 Altitude 0.709 0.386 0.949 0.607 0.721 0.674 Slope degree 1.000* 0.071 0.836 0.930 0.797 0.014 No. of fruit setting 0.219 0.811 0.999* 0.402 0.584 0.472 ph 0.934 0.229 0.956 0.743 0.795 0.040 O.M. 0.850 0.488 0.951 0.797 0.912 0.794 Av. P 2 O 5 0.689 0.617 0.432 0.748 0.232 0.399 K 0.917 0.002 0.995 0.461 0.930 0.516 Ca 0.953 0.908 0.998* 0.952* 0.929 0.924* Mg 0.556 0.892 0.257 0.171 0.202 0.266 *P<0.05. Table 3. Correlation coefficients between the dieback ratio and the cultivation properties under subgrouping in the apple orchards infected by white root rot (n=5) The dieback ratio by white root rot Root stock M.26 (n=5) Sandy loam of surface soil texture (n=3) No underdrain (n=3) Normally effective soil depth Upland on land category (n=3) Tree age 0.526 0.818 0.400 0.656 0.400 No. of planting trees 0.547 0.664 0.400 0.383 0.400 Altitude 0.701 0.886 0.031 0.646 0.031 Slope degree 0.418 0.898 0.566 0.669 0.566 No. of fruit setting 0.807 0.872 0.410 0.750 0.410 ph 0.262 0.168 0.753 0.740 0.753 O.M. 0.230 0.564 0.994 0.526 0.994 Av. P 2 O 5 0.901* 0.878 0.883 0.876 0.883 K 0.525 0.499 0.540 0.380 0.540 Ca 0.184 0.766 0.999* 0.938 0.999* Mg 0.394 0.333 0.920 0.841 0.920 *P<0.05.

52 Research in Plant Disease Vol. 23 No. 1 (Yang과 Mitchell, 1965) 와 Saprolegnia diclina (McCann과 Stuart, 1973) 에서장난기형성및 Phytophthora cactorum (Elliott, 1972) 과 S. diclina (Fletcher, 1979) 에서난포자성숙에필요하며, S. diclina에서는유성기관형성과정에서중요한역할을한다고하였다 (Fletcher, 1979). 또한기주식물의병원력인자의활성이나유전자발현의억제또는세포벽의저항성증대등의방법으로다양한병의억제효과를이끌지만 (Yamazaki, 2001) 사과원의토양에충분한칼슘이있음에도불구하고사과체내에칼슘결핍이일어난다 (Wilsdorf 등, 2012). 이렇듯토양에칼슘시용은수체내공급에있어비효과적이기때문에엽면시비가필요하다는보고 (Yamane, 2014) 처럼자주날개무늬병피해사과원중, 심토가식양토이거나암거를설치한곳또는지목상밭인곳에서는토양내칼슘시용을줄여야한다. 더불어, 엽면시비를통한칼슘공급은토양 ph 상승및붕소등미량원소의불용화를경감시켜수세를좋게하고고사피해를줄일수있을것이라생각한다. 흰날개무늬병에의한고사율과피해사과원재배환경을세분화한상관관계는 Table 3과같았다. 표본수 5개에도불구하고 M.26 대목을사용한사과원에서토양내유효인산함량과유의하게정의상관관계를보였고암거를설치하지않은곳과지목상밭인사과원에서모두고사율과토양내칼슘함량과유의성있게정의상관관계를보였다. 하지만표토가사양토인곳과유효토심이보통인사과원에서는고사율과의상관성은없었다. 이는수직배수가불량한과원에서발병률이높았다는것 (Lee, 1995) 과평탄지와구릉지간에는차이가없었다는것 (Lee, 2002), 양토와사양토에서발병률이많았다는보고와유사하였다. 그러나 Lee (1995) 가보고한대목종류와상관없이 10년이상의노후과원과높은토양 ph에서자주 흰날개무늬병피해가심하였다는것과는차이가있었다. Aoki와 Shimodaira (1959) 는토양내인산공급원으로써 K 2 HPO 4 는자주날개무늬병균의균사두께를증가시키는반면에흰날개무늬병균의균사생장을촉진한다고보고하였다. 이처럼흰날개무늬병피해사과원중, M.26 대목을사용한곳에서는토양내인산시용을줄여야한다고생각한다. 더불어, 암거를설치하지않았거나지목상밭인곳은자주날개무늬병피해사과원처럼엽면시비를통한칼슘공급이고사율경감에효과가있을것이라생각한다. 사과역병에의한고사율과피해사과원재배환경을세분화한상관관계는 Table 4와같았다. 피해사과원 14개소모두 M.26 대목을사용하였는데, 고사율과의상관성을보 인요인은없었다. 경사가있는곳에서는고사율과상관관계를보이지않은반면, 육안상평지인곳은고사율과토양내마그네슘함량이고도의정의상관관계를보였다. 또한, 표토가사양토및양토인곳과심토가사양토인곳에서는상관성이없었지만, 표토가미사질양토인과원과심토가식양토인과원에서는고사율과토양내마그네슘함량이고도의정의상관관계를보였다. 암거를설치하지않은곳에대한고사율과요인과의상관관계는보이지않았지만암거를설치한곳에서는고사율과토양내칼슘함량이유의성있게부의상관관계를보였다. 유효토심이깊은피해과원에대한고사율과요인과의상관관계는없었다. 논과밭구분없이역병이발생하였으나, 논에대해서만고사율과토양내마그네슘함량이고도의정의상관관계를보였다. 역병에의한피해사과원모두저항성인약한 M.26 대목을이용하였다. 이는대목별역병저항성정도가 M.9>Mark>M.26>MM.106 순인것 (RDA, 2003) 과 Jee 등 (1997) 이보고한 M.9과 M.26 대목을사용한후지품종에서심하게발생한다는것과유사하였다. 역병피해사과원중암거를설치한곳에서고사율과토양내칼슘함량과유의하게부의상관관계를보임에따라토양내칼슘시용을늘려야한다고생각한다. 한편, 마그네슘은세균성무름병균과같은펙틴분해효소에대해조직의저항성을증가시키지만마그네슘고농도는칼슘흡수를방해하고병발생을증가시킨다 (Huber와 Jones, 2013) 고하였고, Koohakan 등 (2002) 은토마토모잘록병균 (Pythium aphanidermatum) 의유주자방출을 50% 억제하는칼슘과마그네슘의농도는각각 168 mg/l와 171 mg/l였다고보고하였다. 균류의포자낭발아는유기화합물보다는무기이온이필수적인데, ph 8.0에서 0.3 mm의낮은농도의칼슘및마그네슘이온은 Phytophthora infestans의포자낭발아에매우효과적이고칼륨과나트륨이온은농도에상관없이효과적이지않으며, 나트륨이온을제외한칼륨, 마그네슘, 칼슘이온이 10 mm 이상에서는포자낭발아를억제한다고하였다 (Sato, 1994). Gisi 등 (1977) 은 P. cactorum의포자낭발아를완전히억제하는무기염농도는 4 mm CaCl 2, 1.7 mm MgCl 2, 12.5 mm KCl이었다고하였다. Jee 등 (2000) 은화학비료과용이나미숙퇴비의사용은염류집적등의유해물질로인해잔뿌리가손상되어상처를조장하고역병발생을야기한다고보고하였다. 역병피해과원중경사가육안상평지인곳, 표토가미사질양토인곳, 심토가식양토인곳또는지목상논인곳에서고사율과토양내마그네슘함량과유의하게정의상관관계를보임에따라마그네슘시용을줄인다면칼슘흡수가촉진되어

Research in Plant Disease Vol. 23 No. 1 53 Table 4. Correlation coefficients between the dieback ratio and the cultivation properties under subgrouping in the apple orchards infected by Phytophthora root rot (n=14) The dieback ratio by Phytophthora root rot Root stock M.26 (n=14) South Slope direction Surface soil texture Subsoil texture Underdrain Effective soil depth Land category West flatland Sandy loam (n=5) Loam (n=3) Silt loam (n=5) Sandy loam (n=7) Clay loam (n=6) Yes No (n=10) Deep (n=10) Normal (n=3) Upland (n=7) Lowland (n=7) Tree age 0.055 0.142 0.813 0.229 0.029 0.583 0.147 0.059 0.172 0.192 0.002 0.126 0.469 0.036 0.318 No. of planting 0.258 0.787 0.696 0.889 0.813 0.984 0.301 0.533 0.091 0.156 0.395 0.229 0.991 0.534 0.138 trees Altitude 0.049 0.386 0.216 0.227 0.194 0.382 0.212 0.226 0.223 0.656 0.201 0.114 0.347 0.017 0.051 Slope degree 0.261 0.071 0.113 0.410 0.320 0.899 0.217 0.217 0.234 0.794 0.201 0.241 0.892 0.361 0.386 No. of fruit 0.053 0.811 0.202 0.050 0.353 0.576 0.300 0.280 0.201 0.613 0.226 0.138 0.539 0.284 0.192 setting ph 0.067 0.229 0.751 0.115 0.139 0.323 0.176 0.444 0.197 0.434 0.302 0.043 0.321 0.392 0.083 O.M. 0.217 0.488 0.531 0.346 0.389 0.888 0.354 0.406 0.354 0.420 0.330 0.279 0.908 0.432 0.158 Av. P 2 O 5 0.307 0.617 0.352 0.454 0.372 0.552 0.718 0.314 0.709 0.623 0.023 0.151 0.253 0.222 0.460 K 0.202 0.002 0.434 0.055 0.081 0.606 0.653 0.010 0.604 0.543 0.078 0.074 0.260 0.220 0.096 Ca 0.314 0.908 0.392 0.948 0.261 0.668 0.663 0.112 0.658 0.982* 0.373 0.273 0.416 0.286 0.714 Mg 0.107 0.892 0.782 0.995** 0.380 0.706 0.995*** 0.054 0.994*** 0.731 0.078 0.063 0.567 0.200 0.887** *P<0.05, **P<0.01, ***P<0.001.

54 Research in Plant Disease Vol. 23 No. 1 역병피해가경감될수있다고생각한다. 향후, 토양병에의한사과나무고사율과재배방법, 재배환경및토양물리 화학성과의상관관계는더많은표본수를위해전국을대상으로조사와분석이필요하다. 이를통해토양병피해사과원에대해, 기존의관행재배를벗어난맞춤재배법으로그피해를최소화할수있을것이라판단한다. 요약 이전연구에서충북지방의사과과수원에서토양병에의한사과나무고사율이매우높게나타났다. 본연구에서는토양병에의한사과나무고사율과재배환경과의상관관계를조사하였다. 자주날개무늬병에의한사과나무고사율은토양내칼슘함량과유의하게정의상관관계를보였고, 흰날개무늬병에의한사과나무고사율은토양내유효인산함량과유의하게정의상관관계를보였다. 반면에역병피해사과원 14개소에서는사과나무고사율과재배환경과는유의성있는상관관계가없었다. 세분화한재배환경과의상관관계분석결과는토양내칼슘함량외에과원경사도와착과수가자주날개무늬병에의한고사율에영향을미쳤고, 토양내유효인산함량외에칼슘함량이흰날개무늬병에의한고사율에영향을미쳤다. 과원경사도, 토성, 마그네슘과칼슘함량이사과역병에의한고사율에영향을주었다. 이결과는사과과원의재배법변경에의해토양병에의한사과나무고사율을감소시키는데적용가능할것이다. Conflicts of Interest No potential conflict of interest relevant to this article was reported. Acknowledgement This work was carried out with the support of Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ010014052016) Rural Development Administration, Republic of Korea as well as Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through (Agri-Bioindustry Technology Development Program), funded by Ministry of Agriculture, Food and Rural Affairs (MAFRA) (Grant No. 315003-05-2- HD060). References Aoki, J. and Shimodaira, M. 1959. Studies on the root rot of mulberry trees, caused by Helicobasidium Mompa TANAKA and Rosellinia necatrix (HARTIG) BERLÉSE. (II) Influence of carbon, nitrogen source and phosphate on the growth of two causal fungi. J. Seric. Sci. Jpn. 28: 125-129. Elliott, C. G. 1972. Calcium chloride and growth and reproduction of Phytophthora cactorum. Trans. Br. Mycol. Soc. 58: 169-172. Fletcher, J. 1979. An ultrastructural investigation into the role of calcium in oospore-initial development in Saprolegnia diclina. J. Gen. Mycrobiol. 113: 315-326. Gisi, U., Oertli, J. J. and Schwinn, F. J. 1977. Wasser- und Salzbeziehungen der Sporangien von Phytophthora cactorum (Leb. et Cohn) Schroet. in vitro. J. Phytopathol. 89: 261-284. Huber, D. M. and Jones, J. B. 2013. The role of magnesium in plant disease. Plant Soil 368: 73-85. Jee, H. J., Cho, W. D. and Kim, C. H. 2000. Phytophthora diseases in Korea. Rural Development Administration, Suwon, Korea. 226 pp. Jee, H. J., Cho, W. D. and Kim, W. G. 1997. Phytophthora diseases of apple in Korea: I. Occurrence of a destructive collar rot caused by P. cactorum. Korean J. Plant Pathol. 13: 139-144. Koohakan, P., Ikeda, H., Jaenaksorn, T., Tojo, M. and Kusakari, S. I. 2002. Effects of inorganic elements on the in-vitro growth of Pythium aphanidermatum (Edson) Fitzp. Microbes Environ. 17: 91-97. Lee, D. H. 2002. Etiology and ecology of apple white root rot, caused by Rosellinia necatrix and its biological control. Ph.D. thesis. Kyungpook National University, Daegu, Korea. Lee, D. H., Choi, K. H. and Uhm, J. Y. 2009. Cytochalasin E production by Rosellinia necatrix and its pathogenicity on apple. Res. Plant Dis. 15: 46-50. (In Korean) Lee, S. B. 1995. Etiology and epidemiology of white- and violetroot rot caused by Rosellinia necatrix and Helicobasidium mompa on apple tree and their control in Korea. Ph.D. thesis. Chungbuk National University, Cheongju, Korea. Lee, S. B., Chung, B. K., Jang, H. I., Kim, K. H. and Choi, Y. M. 1995. Incidence of soil-borne diseases in apple orchards in Korea. Korean J. Plant Pathol. 11: 132-138. (In Korean) Lee, S. H., Kwon, Y., Shin, H., Kim, I. J., Nam, S. Y., Hong, E. Y., Kwon, S. I., Kim, D. and Cha, J. S. 2016. Dieback of apple tree by major soil borne diseases in Chungbuk province from 2013 to 2015. Res. Plant Dis. 22: 198-201. (In Korean) McCann, M. and Stuart, M. 1973. The effect of calcium on sexual reproduction in Saprolegnia diclina. Proc. Soc. Gen. Microbiol. 1: 33. [NAAS] National Academy of Agricultural Science. 2010. Method of soil chemical analysis. NAAS, Rural Development Administration, Jeonju, Korea. [NIAST] National Institute of Agricultural Science and Technology.

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