Korean Journal of Environmental Agriculture Korean J Environ Agric (2013) Online ISSN: 2233-4173 Vol. 32, No. 4, pp. 343-347 http://dx.doi.org/10.5338/kjea.2013.32.4.343 Print ISSN: 1225-3537 Research Article Open Access 지베렐린엽면살포가 궁천조생 감귤의착화와과실품질에미치는영향 강석범, 1* 문영일, 2 한승갑, 1 김용호, 1 채치원, 1 최영훈 1 1 농촌진흥청국립원예특작과학원감귤시험장, 2 온난화대응농업연구센터 Effect of Foliar Application of GA 3 on the Flower Bud Formation and Fruit Quality of Satsuma Mandarine (C. unshiu Marc. cv. Miyagawa) Seok-Beom Kang, 1* Young-Eel Moon, 2 Seung-Gab Han, 1 Yong-Ho Kim, 1 Chi-Won Chae 1 and Young-Hun Choi 1 ( 1 Citrus Research Station, National Institute of Horticultural and Herbal Science, RDA, Seogwipo, 699-946, Korea, 2 Agricultural Research Center for Climate Change, National Institute of Horticultural and Herbal Science, RDA, Jeju, 690-150, Korea) Received: 18 November 2013 / Revised: 25 November 2013 / Accepted: 16 December 2013 c 2013 The Korean Society of Environmental Agriculture This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract BACKGROUND: Control of alternate bearing satsuma mandarin in Jeju is very important to maintain the optimum price of fruit and get the sustainable income of farmers. Unlike orange, Satsuma mandarin is well known to sensitive on alternate bearing. We carried out the experiment to know the effect of foliar application of GA 3 on the flowering and fruit quality of satsuma mandarin (C. unshiu Marc. cv. Miyagawa). METHODS AND RESULTS: To experiment, the treatments consist of control, different concentration of GA 3 (25, 50 and 100 mg/l), machine oil emulsion 100 times and mixture of various concentration of GA 3 (25 and 50 mg/l) with machine oil emulsion 100 times which it was applied on 15 year-old Miyagawa satsuma mandarin at December 29, 2011. Foliar application of GA 3 in winter reduced the flowering of satsuma mandarin. Flower-leaf ratio was significantly reduced at 100 mg/l GA 3, while no differences observed in low concentration of GA 3 (25 and 50 mg/l). However, it was significantly decreased to 0.19 in application of GA 3 25 and 50 mg/l with machine oil emulsion 100 times mixture. Number of leaves per fruit was significantly increased as foliar application of GA 3 also it reduced the fruits remarkably. Soluble solid contents and Hunter s a of peel color ratio showed no difference among GA 3 single treatments, but it was reduced in GA 3 25 and 50 mg/l with machine oil emulsion 100 times mixtures significantly. From the results, it has been found that higher GA 3 concentration can reduce the number of flowers on the alternate bearing of satsuma mandarin. However, it was found that lower concentration of GA 3 with machine oil emulsion mixture 100 times can reduce flowering. CONCLUSION(S): The foliar application of GA 3 (100 mg/l) can alleviate alternate beraring. Also, mixture of lower concentration of GA 3 with machine oil emulsion 100 times can retard flowering more significantly while it needs further confirmation. Key words: Alternate bearing, Flowering, Fruit quality, GA 3 * 교신저자 (Corresponding author), Phone: +82-64-730-4173; Fax: +82-64-730-4111; E-mail: hortkang@korea.kr 343
344 KANG et al. 서론 온주밀감은다른과수에비해해거리를심하게하는과종 이다 (Iwahori and Oohata 1981; Ogata. et al., 1995). 감 귤재배지에서해거리가발생하면착과량이적은해에는생산량감소에의한가격폭등과다음해에발생할과다착과로과잉생산에의한감귤가격폭락이반복되는문제가발생되고있다. 이에온주밀감에서의해거리를경감하기위해손으로하는기계적인적화방법은많은비용이발생되어현실적으로어렵고수확기에부분적으로비상품과를적과하는방법을이용하고있다 (Falivene and Hardy, 2008a). 따라서온주밀감에서는과다착과가예상되는해를대비하기위해 NAA와같은화학적적화및적과에대한연구들이수행되고있다 (Iwahori and Oohata, 1976; Falivene and Hardy, 2008b). 그러나적화제로나온제제들도외부의기상환경에민감하게반응하여안정적인착화량조절에는어려움이있는실정이다. 이에감귤에서과다착과에의한해거리를경감시키기위해다양한방법들이연구되고있는데그중생장조정제를이용한해거리경감연구들이연구가많이진행되고있다. 특히생장조절제중지베렐린은작물의영양생장에밀접하게관여하는식물호르몬으로감귤류의부피경감, 수확기연장및저장성증진 (Greany et al., 1994; Pozo et al., 2000) 에도이용하고있지만, 감귤의꽃눈분화기에수관살포로꽃눈분화를억제하여다음해착화량을줄였다는보고들이있다 (Pharis and King, 1985; Takaki et al., 1989; Moon et al., 2003). 그러나생장조절제인지베렐린은고농도로이용하게되면과실의착색이불량해지는문제도있기에이용에는주의를해야한다. 한편기계유유제는감귤에서는응애류의방제 (Huang and Zhang, 1990) 에주로이용되는데지베렐린과혼용살포시그효과가오래지속된다는보고가있다 (Takahara et al., 1990). 따라서본연구는 궁천 조생감귤의꽃눈발생에미치는지베렐린의엽면살포효과를검증하여노지감귤의해거리경감기술을개발하기위한기초자료를만들기위해수행하였다. 재료및방법 시험재료시험재료는제주특별자치도서귀포시남원읍하례리에위치한농촌진흥청국립원예특작과학원감귤시험장에서관리되고있는탱자대목에접목된 15년생 궁천 조생온주밀감 (Citrus unshiu Marc. cv. Miyagawa) 을이용하였으며포장관리는국립원예특작과학원감귤시험장포장관리에준하여하였다. 시험처리를위해생육과착화량이균일한 28주의나무를선정하여 7처리 4반복의난괴법으로 2011년 12월부터 2012년 12월까지시험을수행하였다. 시험처리시험처리는무처리구인대조구를포함해서, GA 3(Sigma chemical co., USA) 단용처리 (25, 50, 100 mg/l), 기계유유제 ( 한국삼공, 95%) 100배, GA 3 25 mg/l + 기계유유제 100배, GA 3 50 mg/l + 기계유유제 100배의 7처리를과실수확이끝난 2011년 12월 29일에수관전체에걸쳐고루엽면살포하였다. 처리시에는시험처리가끝난후엽면에살포된지베렐린 (GA 3) 약제가충분히수체에흡수되도록처리후 1 2 일내에비나눈이오지않는날을선정하여처리를하였다. 착화량및착과량조사착화량은 1주당동서남북 4방위에서잎이 200 300매달린 4개의측지를표지하여전체의잎수를센후 5월 15일꽃이만개되기전에꽃수를조사하여그비율을구엽 1매당꽃수와열매 1개당잎수로산정하였다. 착과량은동일한조사가지에대해 2차생리적낙과가끝난후착과된과실수와착엽된잎수를 7월 23일에조사하였다. 과실품질조사수확당일에각나무당 10과씩을무작위로선정하여과실의횡경과종경은버니어캘리퍼스로측정하고, 착색도는색차계 (CR-400, Minolta, Japan) 을이용하여각과실의적도면 3곳에대해 Hunter s a값을측정후평균값으로나타내었다. 같은과실에대해과중을측정한과피를벗기고과육중을재었으며과피두께는각각의과실껍질 4개를모아서버니어캘리퍼스로측정후평균하였다. 과육시료를착즙후당함량은굴절당도계 (PR-101, Atago, Japan) 로측정하였으며산함량은 5 ml의과즙에증류수 20 ml를넣고 0.1 N NaOH으로 ph 8.1에이르기까지들어가는적정량을구연산으로환산하였다. 과실의당산비는당도에산함량을나눠값을구하였다. 통계처리본시험에서얻어진자료에대해서통계프로그램 SAS Enterprise Guide 3.0을이용하여던칸다중검정 (p=0.05) 으로처리간의유의성을분석하였다. 결과및고찰 온주밀감의해거리경감을위하여노지 궁천 조생을시험품종으로하여지베렐린과기계유유제를이용한착화량조절시험을수행하였다. 지베렐린은식물의생장호르몬중생식생장을억제하고영양생장을유도하는호르몬으로자연계에많은종류가있지만 GA 3( 지베렐린 ) 가작물재배에서다양하게이용되고있다. GA 3 를작물에이용할때는식물체가효과적으로흡수하게하기위해엽면살포를주로이용하고있는데감귤에서는이를통해수체내꽃눈분화를억제하여다음해꽃눈발생을줄여해거리발생조절에효과를얻고있다 (Monselise and Halevy, 1964;Hirose, 1968; Lenz and Karnatz, 1975; Iwahori and Oohata, 1981; Guardiola et al., 1982; Davenport, 1983). GA 3 엽면살포가 궁천 조생온주밀감의착화에미치는영향은 Fig. 1에나타내었다. 수확이끝난후겨울철지베렐린을엽면살포한결과무처리구에비해지베렐린처리구들에
Effect of Foliar Application of GA 3 on the Flower Bud Formation and Fruit Quality of Satsuma Mandarine (C. unshiu Marc. cv. Miyagawa) 345 서봄철착화량이뚜렷하게감소함을확인할수있었다. 구엽당화엽비로보면낮은농도의지베렐린 25 mg/l 에서는 0.85 로대조구의 0.87 과비교해차이가없었지만지베렐린농 도가높아짐에따라지베렐린 100 mg/l 에서는 0.26 로화엽비가뚜렷하게감소됨을확인할수있었다. 반면기계유유 제를단용으로살포했을때는화엽비에큰차이를나타내지는않았지만지베렐린 25와 50 mg/l에기계유유제를혼용살포했을때꽃의착화량이뚜렷하게감소하여화엽비도다른처리구들에비해유의하게낮은결과를나타냈다. 특히처리구중가장낮은수준인지베렐린 25 mg/l와기계유유제혼용살포에서화엽비가 0.19를나타내어지베렐린 50 mg/l과기계유유제를혼용살포한처리구 (0.19) 와같은가장낮은수준의화엽비를나타내었는데이는지베렐린 100 mg/l 단용처리 (0.26) 에서도볼수없었던결과로기계유유제를혼용살포시낮은수준에서도효율적으로착화량을줄일수있음을확인하였다. Takahara 등 (1990) 도지베렐린을단용처리할때보다 95% 기계유유제를 50배와 100배로지베렐린에혼용살포하였을때나 97% 기계유유제를 100배혼용살포하였을때봄철온주밀감의꽃눈발생억제효과가뚜렷하였다고하여본시험의결과와유사한결과를나타내었다. 지베렐린처리를이용한감귤꽃눈조절에대해서 Guardiola 등 (1982) 은 11월초부터봄철발아기까지지베렐린처리가스위트오렌지 (C. sinensis (L.) Osbeck), 온주밀감 (C. unshiu Marc.), 클레멘타인만다린 (C. reticulata Blanco) 의꽃눈분화를낮췄다고하였다. Munoz-Fambuena 등 (2012) 은스위트오렌지에 GA 3 살포시대조구에비해 100 마디당꽃수가대조구에비해 72% 까지감소됐다고하였으며 Moon 등 (2003) 은온주밀감에서 GA 3 처리에의해착화수는유의하게감소하였고 GA 3 처리농도가높아짐에따라착과율도증가하였다고하여감귤에지베렐린처리가꽃눈발생을감소시키고있음을알수있었다. 지베렐린엽면살포가노지 궁천 조생온주밀감의착과량에미치는영향은 Table 1에나타내었다. 생리적낙과가끝난후남아있는착과량에대해조사한결과무처리인대조구에서는조사결과지당착과량은 38.8개, 과일당엽수는 776매 로처리중착과량은가장높고반면착엽수는적었다. 그러나지베렐린처리구에서는착과량이감소하고과일당엽수는많아지는결과들을나타냈다. 특히지베렐린단용처리구에서는농도가높아짐에따라유의하게착과량이감소하는결과를나타냈다. 반면기계유유제를단독으로엽면살포했을때는차이를나타내지않았지만지베렐린단용처리구에기계유유제를혼용살포했을때는단용처리구에비해처리효과가더높게나타났다. 지베렐린 25 mg/l에기계유유제를혼용했을때착과량이 17.8개에과일당엽수는 68매로지베렐린 25 mg/l 단용처리구 ( 착과량 24.5개 ) 의 43매에비해착과량감소에따른엽수증가를확인할수있었으며지베렐린 50 mg/l에기계유유제혼용살포에서는 13.8개에과일당엽수는 70매로지베렐린 50 mg/l 단용처리구 ( 착과량 23.8개 ) 의 41매에비해처리효과가더크게나타나착과수를더욱감소시킴을확인할수있었다. 그러나본시험에서는지베렐린 100 mg/l 단용처리했을때착과율은 10.8개에과일당엽수는 123매로착과량을처리구내에서가장효과적으로제어하였다. 이러한결과는 Fig. 1의지베렐린 25와 50mg/L에기계유유제 100배를혼용살포한처리구의화엽비감소율이보다많았던것에비해지베렐린 100 mg/l 단용살포에서착과율이가장적었다는것은실질적으로화엽비대비착과율에미치는영향이지베렐린고농도에서크다는것을나타낸다고볼수있으며앞으로이부분에대해보다많은연구가필요할것으로판단되었다. 지베렐린처리가온주밀감의과실품질에미치는영향은 Table 2에나타내었다. 과실의직경과과중은대조구인무처리구에비해지베렐린처리구에서다소커지는경향을나타냈다. 반면과실내당함량은대조구에비해지베렐린단용처리구에서는차이가없었으나착화량감소효과가높았던지베렐린 25와 50 mg/l에기계유유제를혼용살포한처리구에서 0.7 Brix 감소하는결과를나타내었으며착색도를나타내는 Hunter s a 값도지베렐린단용처리에서는차이가없었으나지베렐린과기계유유제를혼용살포한처리구에서뚜렷하게값이떨어져착색이지연되는결과를나타냈다. Table 1. Effect of foliar application of GA3 on the fruiting of Miyagawa satsuma mandarin in open field Treatment No. of fruit (ea/branch) No. of leaves (ea/branch) No. of leaves per fruit(ea) Control 38.8a ab 776c 20.2b GA 3 25 mg/l 24.5ab 1051abc 42.9ab GA 3 25 mg/l + Machine oil emulsion 100 times 17.8ab 1207ab 68.0ab GA 3 50 mg/l 23.8ab 971bc 40.9ab GA 3 50 mg/l + Machine oil emulsion 100 times 13.8b 965bc 70.2ab Machine oil emulsion 100 times 31.0ab 949bc 31.8ab GA 3 100 mg/l 10.8b 1323a 123.1a a DMRT at p = 0.05 b Date: July 23, 2012
346 KANG et al. Table 2. Effect of foliar application of GA 3 on the fruit quality of Miyagawa satsuma mandarin in open field Treatment Fruit diameter ( mm ) Fruit weight (g) Peel thickness ( mm ) Soluble Solids ( Bx) Acidity (%) Sugaracid Hunter s a ratio values Control 62.7a ab 101b 2.7ab 10.5a 1.23b 8.53a 21.1ab GA 3 25 mg/l 63.5a 104ab 2.7ab 10.6a 1.53a 6.95a 19.9ab GA 3 25 mg/l + Machine oil emulsion 100 times 68.3a 133a 2.8a 9.8a 1.36ab 7.20a 18.8ab GA 3 50 mg/l 62.8a 103ab 2.4b 10.5a 1.24b 8.58a 22.5a GA 3 50 mg/l + Machine oil emulsion 100 times 66.0a 119ab 2.7ab 9.8a 1.49a 6.72a 13.4b Machine oil emulsion 100 times 64.4a 108ab 2.6ab 10.6a 1.24b 8.67a 24.0a GA 3 100 mg/l 63.8a 108ab 2.4b 10.7a 1.44ab 7.44a 22.7a a DMRT at p = 0.05 b Date: November 12, 2012 본시험에서 Fig. 1. 과 Table 1에서살펴본바와같이지베렐린처리시기계유유제를혼용했을때는 25 50 mg/l 에서는지베렐린단용처리에비해착화량과착과량을떨어뜨리는데더효과적인결과를나타냈으나과실의품질에있어서는지베렐린 100 mg/l 처리구에비해당함량이낮은결과를나타냈다. 즉저농도의지베렐린에서도기계유유제혼용살포로지베렐린의착화억제효과는오래지속되었지만이러한영향이과실의당함량과착색에도부정적인효과를미쳐지베렐린에기계유유제를혼용할경우에는과실의당도감소시키지않고적절히착과도줄일수있는적정혼용수준을찾아야할것으로판단되었다. Takahara 등 (1990) 도지베렐린에기계유유제를혼용살포시약효가더욱확실하게영향을끼친다고하였는데실질적인지베렐린의재배현장에서의이용을위해서는과다착과가예상될때해거리도경감시키고과실의품질도떨어뜨리지않는처리수준을찾는것이중요하였다. Fig. 1. Effect of foliar application of GA 3 on the flowering of Miyagawa satsuma mandarin in open field. a DMRT at p = 0.05. b Date: May 15, 2012. c MOE 100: Machine Oil Emulsion 100 times. 본시험에서는지베렐린 100 mg/l 처리에서수체의착화량과착과량도줄이고과실의품질도떨어뜨리지않아효과적인역해거리를유발하기위한좋은지벨렐린처리수준이 라고판단되나지베렐린 25 50 mg/l에기계유유제 100배를혼용살포한처리구또한과실의착색지연과당함량저하는수확시기를조금만늦춘다면해결될수있기에앞으로검토할만한혼용살포처리라고생각된다. 노지감귤재배에서해마다찾아오는해거리는감귤재배농가들에게결코바람직하지않는현상이다. 이감귤의생리적현상인해거리를방지할목적으로지베렐린과기계유유제를적절히사용하면인위적으로해거리를조절하여농가가원하는시기에착화를보다효율적으로유도할수있을거라판단되며앞으로보다많은연구들이다양한품종과재배작형에서이루어진다면감귤이보다안정적으로생산되어적정한가격을유지할것으로판단된다. References Davenport, T.L., 1983. Daminozide and gibberellin effects on floral induction of Citrus latifolia, HortScience 18, 947-949. Falivene, S., Hardy, S., 2008. Hand thinning citrus, Primefact 789, 1-3a. Falivene, S., Hardy, S., 2008. Chemical thinning citrus, Primefact 788, 1-3b. Greany, P.D., McDonald, R.E., Schroeder, W.J., Shaw, P.E., Aluja, M., Malavasi, A., 1994. Use of gibberellic acid to reduce citrus fruit susceptibility to fruit files, American Chemical Society Symposium 557, 39-48. Guardiola, J.L., Monerri, C., Agusti, M., 1982. The inhibitory effect of gibberellic acid on flowering in Citrus, Physiol. Plan. 55, 136-142. Hirose, K., 1968. Control of citrus flower bud formation. 1. The effect of gibberellic acid spraying on flower bud formation in satsuma orange, Bull. Horot. Res. Sta. 8, 1-11.
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