본 연구는 과육색이 노란 국내 육성 키위 ‘Jecy Gold’ 품종의 수확 적기 판정과 후숙 후 당도 예측 방법을 개발하고자 수행하였다. 과실 생육 단계 중 과실 비대기는 BBCH 70~78(DAA 10~110), 과실 성숙 단계는 BBCH 80(DDA 140), 당도가 급격히 증가하는 시기는 BBCH 83(DDA 160), 과육이 부드러워지는 시기는 BBCH 87(DAA 190), 과실이 노화되는 시기는 BBCH 90(DDA 210)이었다. 이러한 결과를 토대로 BBCH 83(DAA 160일)에서 수확하는 것이 가장 바람직할 것으로 판단되었다. 후숙 전 과실 건물률과 후숙 후 당도가 정의 상관관계를 보였다. 후숙 전 건물률을 이용하여 후숙 후 당도를 예측하기 위하여 회귀분석을 수행한 결과, 후숙 후 당도(y)=1.1841ⅹ건물율(x)-3.5244(r²=0.9338)으로 나타났으며, 실측 값과 예측 값을 이용하여 회귀분석을 수행한 결과, 상관계수 R² 값이 0.86으로 높게 나타났다. 따라서 수확 시기의 건물률을 이용하면 후숙 후 당도를 추정할 수 있을 것으로 판단된다.

The study aimed to evaluate the damage persistence during subsequent years in kiwifruit vines defoliated by strong wind such as typhoons. Artificial defoliation was treated on five-year-old ‘Jecy Gold’ kiwifruit vines grown in a plastic house in year 2013 and 2014 by applying four levels of defoliation, i.e., 0, 50, 75, and 100% in August 23, 2013 and 100% defoliation in July 28 and August 29, 2014, respectively. Return bloom and fruit quality were investigated in the following two years, 2014 and 2015. A significant reduction in number of flowers per shoot in the following year, 2014 was recorded for the vines with 50%, 75%, and 100% defoliations treated in 2013 compared to the control vines. The number of flowers per florescence was significantly reduced for defoliated vines. Nevertheless, the fruit quality parameters, i.e., fruit length, width, weight, firmness, TSS, acidity, and dry matter content were not significantly different for the defoliated vines compared to the control vines. The vines defoliated in 2013 at 75% and 100% levels showed a significant reduction of number of flower per inflorescence in 2015 compared to the 0% defoliation. However, the number of flowers per shoot and fruit quality were not significantly different. Also, the number of flowers per inflorescence in 2015 was significantly reduced by July 28, 2014 or August 29, 2014 defoliation compared to non-defoliated vines while the number of flowers per shoot, and fruit quality in 2015 were not significantly different between treatments and control vines. Accordance with the present findings, the flowering is considerably affected by the shortage of carbohydrate supply than the fruit quality of ‘Jecy Gold’ kiwifruit. In addition, the negative impacts of severe defoliation in flowering of ‘Jecy Gold’ kiwifruit might be persisted more than one season from the time of defoliation and consequently, the total yield might be reduced in the following seasons after defoliation.

동일한 무가온 하우스 내에서 화산회토양(흑색, 농암갈색) 및 비화산회토양(암갈색)에 재배되고 있는 5년생 참다래 ‘제시골드’(Actinidia chinensis cv. Jecy Gold) 과실의 품질에 미치는 영향을 토양유형에 따라 비교하였다. 토양유형별 토양수분포텐셜은 암갈색 비화산회토양이 가장 낮았다. 개화 후 과실 종경의 비대는 토양에 따른 차이를 나타내지 않았고, 횡경비대는 암갈색 비화산회토양이 흑색 및 농암갈색 화산회토양보다 작은 경향이었다. 과실의 당도는 개화 후 140일까지는 차이가 없었으나, 140일 이후에는 암갈색 비화산회토양이 흑색 및 농암갈색 화산회토양보다 높았다. 수확 후 과실의 산함량 및 경도는 토양유형에 따라 차이가 없었다. 과즙의 과당, 포도당 및 자당함량은 각각 암갈색 토양이 4.45±2.08, 5.43±1.13, 및 2.40±0.40%, 흑색 토양이 2.51±0.55, 3.53±0.86 및 0.80±0.33%, 농암갈색 토양이 2.55± 0.47, 3.53±0.73 및 0.73±0.38% 이었다. 따라서 과실의 당도는 토양특성에 따라 영향을 받는다. 이러한 원인은 비화산회토양인 암갈색 토양이 화산회토양인 흑색 및 농암갈색 토양보다 토양수분 보유능력이 낮기 때문으로 판단된다.

“Jecy Gold” is a new kiwifruit variety developed at the National Institute of Subtropical Agriculture (NISA), RDA in 2003, which was for the utilization as fruit with yellow flesh and high soluble solids. This variety was selected from seeds obtained from the cross breeding between Actinidia chinensis cv. “Golden Yellow” and A. chinensis cv. “Songongu” with yellow flesh in 1997. Seedling and line selections were conducted from 1998 to 1999, and characteristic trials were carried out from 2000 to 2002. After developed, it was also conducted to the test of adaptability in kiwifruit orchards of Jeju island from 2003 to 2006. The branch of “Jecy Gold” sprouts strongly and the color of leaf is slightly dark green. The shape of fruit is obovoid, and the color of peel is yellowish-brown without hair. The average weight of fruit is 128.4 g. The core is middle and soft, the percicarp is golden yellow, and the texture is fragile and juicy. Soluble solids concentration is 14.8 oBrix. The total acid content is 0.69% and the fruit yield is higher about 30% than that of A. deliciosa cv. “Hayward”. The content of vitamin C is higher than that of A. deliciosa cv. “Hayward”. The harvesting time is from late October to early November and the fruit can be preserved about 90 days at 2°C. This variety can be planted bellow 100 m sea level and should be grown under shelter to prevent from disease and cold. This variety will be cultivated about 100 ha by 2011 in the southern part of Korea and has been supplied about 10 ha in 2007.