This study was accomplished to investigate the effects of the night temperatures on the dark respiration and fruit quality of ‘Heukgoosul’ grape at ripening time. The weight of cluster and berry increased significantly at 20oC than 30oC in night temperature. The length and diameter of berry harvested from the 20oC and 25°C treatments also increased significantly. But there were no differences in the cluster length and diameter as well as the number of berries per cluster. When the amount of CO2 uptake was examined, the dark respiration decreased at 20°C in comparison with 30°C. On the other hand, the anthocyanin content of fruits harvested from the 20°C treatment was higher 38.8 μg·cm-2 than that of 30°C 27.7 μg·cm-2. Hunter’s value such as L(brightness), a(red chromaticity) and b(yellow chromaticity) showed the significance between 20°C and 30°C treatments. Soluble solid content and acidity of berry fruits harvested from the 20°C treatment increased respectively by 3.4 °Brix and 1.6 times. With consideration of the main characteristics of fruit harvested at 30°C, the sugar-acid ratio 72.6% was lowered and the color chart showed the low value 7.1, therefore, the overall fruit quality was deteriorated. When the production yield rates of first harvest 23.6% and second harvest 44.7% were compared, the 20°C treatment could move up the harvest time earlier.

개량일자형 수형과 웨이크만식 수형은 우리나라에서 가장 널리 사용되는 수형으로 ‘캠벨얼리’와 같은 단초 전정형 품종에 장점을 가지고 있다. 본 시험에서는 웨이크만식 수형과 개량일자형 수형에서의 노동시간과 노동 강도를 비교하였다. 그 결과, 송이다듬기는 웨이크만식 수형에서 17.3 시간/10a, 개량일자형 수형에서 12.3/10a 시간이 소요되었다. 봉지씌우기는 웨이크만식 수형에서 10.1 시간/10a, 개량일자형 수형에서 8.2 시간/10a가 소요되었다. REBA index를 이용하여 송이다듬기와 봉지 씌우기의 노동강도를 확인한 결과 웨이크만식 수형에서 13점, 개량일자형 수형에서 8.6점을 나타내었다. 한편, 개량일자형 수형에서는 포도나무 신초들의 절간장과 절간굵기의 강한 생장도 감소하였다. 결과적으로 개량일자 형 수형은 우리나라의 포도과원 생력화에 더욱 편리한 수형이다.

The table grape 'Hongisul' with strong cold and disease resistance has high sugar, low acidity and excellent palatability. However, this grape has a problem of poor coloring. This study was carried out to improve the fruit color through leaf removal treatments in ‘Hongisul’ grapes. The leaf removal treatment involved removing 2 leaves and 4 leaves around the grape cluster at the start of veraison. The light exposure value of clusters increased 4 leaves removal clusters compared with those of the 2 leaves removal and non-treatment. However, there was no difference in the ambient temperature among the three treatments. The improved light exposure caused by leaf removal increased soluble solids content and the ratios of hunter a value (red) in the grape skins, while total acidity had decreased more in the leaf removal. These findings are expected to improve viticultural practices with the aim of producing red-colored grape.

본 연구는 30oC 이상 고온기 포도 착색장해를 경감하기 위하여 차광 정도에 따른 포도 광합성과 과실특성 및 품질과의 관계를 구명하고자 국내육성 ‘자랑’과 ‘흑보석’ 포도를 가지고 수행하였다. 1. ‘자랑’ 포도는 오전 10시 무처리 대비 차광 30%에서 오전에는 5.1 μmolCO2·m-2·s-1, 오후에는 9.4 μmolCO2·m-2·s-1 광합성률이 높아 오전부터 차광하는 것이 효과적이었으며, ‘흑보석’ 포도는 무처리 대비 오전 10시에 –3.1 μmolCO2·m-2·s-1로 광합성률이 저하하고, 오후에 7.6 μmolCO2·m-2·s-1 광합성률이 증가하여 오후 고온에서 30% 차광 처리하는 것이 효과적이다. 차광 30%와 50% 처리간에는 광합성률 차이가 인정되지 않았다. 2. ‘자랑’ 포도를 10시부터 17시까지 평균온도는 무처리 대비 30% 차광 엽온은 4.2oC, 50% 차광 엽온은 4.8oC 낮았으며, ‘흑보석’ 포도는 10시부터 16시까지 평균온도는 무처리 대비 30% 차광 엽온은 4.1oC, 50% 차광 엽온은 4.9oC 낮았다. 두 품종 모두 무처리와 차광 처리간의 범위는 4.8 ~ 4.9oC로 차광이 엽온 저하에 효과적이었으며, 차광처리 간에는 큰 차이가 없었다. 3. 과실 특성에 있어서는 ‘자랑’과 ‘흑보석’ 포도의 과실중, 당함량, 산도는 무처리구와 인공차광 처리구 간 유의성이 있었다. 하지만 과방길이, 직경, 과립수는 처리구 사이에 유의성이 인정되지 않았다. 4. ‘자랑’ 포도 안토시아닌은 무처리 28.88 μg/cm2 대비 차광 30%가 42.8 μg/cm2로 1.5배 높았으며 명도(L)은 차광 처리에서 낮고, 적색도(a)는 무처리가 높으며, 황색도(b)는 차광 처리에서 낮으나, 차광처리 간에는 차이를 보이지 않았다. ‘흑보석’ 포도는 안토시아닌, 명도(L), 황색도(b)는 처리 간 유의성이 없었으나, 적색도(a)는 차광 30%에서 유의성을 보였으나, 차광 처리 간에는 유의성이 인정되지 않았다.

과피색의 경우 정량적인 지표로서 주로 Hunter L*a*b* 값을 이용하나 이 값으로 과피색, 과실의 품질을 간접적으로 확인하기에는 어려운 점이 있다. 따라서 본 실험에서는 포도 착색지수로서 제안된 CIRG(Color Index for Red Grapes) 값의 활용도를 평가하여 포도 착색의 객관적인 평가지수로서의 가능성을 검증하고자 하였다. 이를 위해 포도가 착색이 시작되는 시기부터 과립을 채취하여 과피색과 당도, 산도 등의 품질 인자를 측정하여, CIRG 값과의 상관을 분석하고 회귀식을 도출하였다. CIRG 값과 안토시아닌 함량은 CIRG 값이 증가함에 따라 안토시아닌 함량은 지수적으로 증가함을 알 수 있었으며, 결정계수는 ‘캠벌얼리’와 ‘흑보석’ 모두 0.8500 였다. CIRG 값과 당도는 ‘캠벌얼리’가 0.7758, ‘흑보석’이 0.7253으로 높은 결정계수를 나타냈으며, 산도 또한 각각 0.7279, 0.663으로 비교적 높은 결정계수 값을 나타내었다. 따라서 적색포도를 대상으로는 CIRG값이 Hunter L*a*b*값에 비해 과실품질을 추정하는데 있어 보다 높은 신뢰성을 가지고 있는 것을 확인하였다.

The GA application on grapevines induces parthenocarpy, fruit set without fertilization, and the inhibition of pollen tube growth. But the molecular mechanism underlying this inhibition is not understood. Similar defective pollen tube growth within the transmitting tract has been reported in the mutant of GABA transaminase (GABA-T), referred to as pollen-pistil-interaction2 (pop2) in Arabidopsis. In spite of the similarity of pollen tube growth inhibition observed in GA-applied grapevines with that of pop2, only the effects of GABA on stress responses in grapevines have been reported. In present study, transcriptional changes of Vitis GABA metabolic genes, together with changes in GABA levels with or without GA application were analyzed to define how GA application restrained the pollen tube growth in grapevines. A GA solution (Dongbu, Seoul, Korea) at 100 ppm was onto inflorescence clusters 14 days before full bloom (DBF) and clusters were harvested at 0, 1, 2, 4, 7, 9, 12, 14, 16, and 19 days after GA application. Harvested inflorescence samples were immediately frozen in LN2 and extracted RNA and amino acid. The GABA contents were analyzed using high-performance liquid chromatography (Agilent 1100 HPLC, Agilent Technologies, Inc., Santa Clara, USA) equipped with a C18 column (4.6 mm×150 mm, 3.5 μm/VDS optilab, Berlin, Germany), according to the manufacturer’s instructions. Without GA application, the simultaneous high expressions of VvGAD1, VvGAD4 and VvGABA-T2 during 10 to 5 days before full bloom (DBF) showing the activation of GABA metabolism. But the contents of GABA were low before 2 DBF, and it peaked only at near full bloom when expression levels of VvGABA-T2 remained low. After GA application, the contents of GABA were constant during 10 to 5 DBF, although transcription levels of both VvGAD1 and VvGABA-T2 rapidly declined less than 30% of the levels observed without GA application. However, the GABA levels increased more than 2-fold only at near full bloom, compared to those without GA application, and at that time, expression levels of VvGAD1 up-regulated more than 3-fold and those of VvGABA-T2 kept low. But other amino acid contents did not show significant changes. In case of VvSSAHDs, their transcriptional changes with or without GA application were not correlated with GABA levels. These results indicates that GABA levels before pollination is tightly regulated, but GA application alters the GABA-shunt to accumulate excess GABA more than needed for proper pollen tube growth at full bloom. Gibberellin application alters the GABA-shunt to accumulate excess GABA resulting in inhibition pollen tube growth in grapevines.

The tight regulators of fruit set initiation, gibberellin (GA) and auxin, have been applied for decades to induce parthenocarpy, fruit set without fertilization. The integration of GA and auxin signaling mediated by either GA or auxin application during parthenocarpy has been actively reported in tomato, and recently we reported that GA application at pre-bloom also activating auxin signaling and down-regulated negative regulators of fruit set initiation in grapevines. However, the activation of auxin signaling upon GA application without up-regulation of auxin biosynthesis is still unclear. In this study, expression patterns of three auxin efflux transporter genes, VvPIN1a, VvPIN2 and VvPIN4, were monitored during inflorescence development in ‘Tamnara’ grapevines with or without GA application. Without GA application, transcription levels of VvPIN1a and VvPIN4 gradually increased from 14 days before full bloom (DBF) to 2 and 5 days after full bloom (DAF), respectively, except down-regulation of VvPIN1a during 5 DBF to full bloom. However, VvPIN2 expression declined steadily after peaking at 10 DBF. With GA application, VvPIN1a did not show significantly different expression patterns when compared to no GA application, with the exception of 4-fold up-regulation at full bloom, but transcription of VvPIN4 was reduced between 5 and 2 DBF. In addition, VvPIN2 was down-regulated between 12 and 10 DBF by more than 50% compared to levels in the absence of GA application. These reductions of both VvPIN2 and VvPIN4 with GA application prior to pollination suggest that GA application might regulate auxin distribution, instead of auxin biosynthesis, to activating auxin signaling during parthenocarpic fruit initiation.

무핵 포도 품종 육성 시, 주요 교배친으로 사용되는 무핵 품종 20점의 유연관계를 분석 하고, 무핵 형질과 연관된 P3_VvAGL11 마커의 이용 가능성을 검토하였다. SSR 마커 30종을 이용한 결과 218개의 대립인자가 확인되었고, 마커 당 대립인자 수는 평균 7.3개였다. PIC (Polymorphism information contents) 값은 SSR 마커에 따라 0.052에서 0.883으로 나타났고 평균 값은 0.442이었다. 또한 P3_VvAGL11 마커를 이용하여 포도 무핵 유전자원 20 점을 분석한 결과 ‘Sultanina’와 ‘Kishmish Chernyi’ 품종으로부터 유래한 18개 무핵 품종에서 무핵 특성 특이적인 밴드가 증폭되었다. 선발된 218개의 다형성 밴드를 이용하여 UPGMA 군집분석한 결과 유사도 지수 0.722를 기준으로 4개의 그룹으로 구분할 수 있었다. 각 그룹은 교배친으로 사용된 품종들의 유전적 background에 유럽종(V. vinifera), 미국종(V. labrusca), 그리고 이들의 종간교잡종인 V. labruscana의 비율에 따른 분류와 일치하였다. 품종 간 유전적 유사도는 0.592에서 0.844의 범위로 나타났으며 평균 유사도 지수는 0.715였다. 가장 높은 유사도 지수를 나타낸 것은 ‘Emerald Seedless’와 ‘Ruby Seedless’ 품종 간이었고, 가장 낮은 유사도 지수를 나타낸 것은 ‘Beauty Seedless’와 ‘Honey Seedless’ 품종 간이었다. 이러한 결과는 무핵 포도 품종 육성 시, 유전적 background가 다양한 양친 선정 및 무핵 교배 실생 조기 선발에 활용 될 수 있을 것이다.

Gibberellic acid (GA) is a well-characterized plant hormone, which plays a critical role in various plant growth and development. including stem elongation, floral indcution and seed development. GA is known to cause enlargement of ripening fruits and, especially in grapevines, GA shows a unique function: the induction of seedlessness in seeded grape varieties. However, despite extensive previous studies about GA, there has been no clear verification of the mechanism that induces seedlessness in grapes. To understand how GA treatment results in artificial parthenocarpy of seeded grapes at molecular levels, we analyzed transcriptional changes in seeded grapes with and without GA application in various inflorescence developmental stages using RNA-seq. At 14 days before flowering (DBF), seeded grapes were treated with 100 ppm GA and clusters were collected at three developmental stages: 7 DBF, full bloom, and 5 days after flowering (DAF). Of a total of 28,974 genes that were mapped to grape genome reference sequences, 7,013 and 9,064 genes were up- and down-regulated, respectively, in the GA-treated grape as compared to the non-GA-treated control at 7 DBF, full bloom, and 5 DAF. Clustering analysis revealed that these genes could be grouped into 9 clusters with different expression patterns. We also carried out functional annotation based on gene ontology categories. There were significant differences in the expression of the GA and auxin-related gene families. These findings expand our understanding of the complex molecular and cellular mechanisms of GA-induced parthenocarpy of grapes and provide a foundation for future studies on seed development in grapevines.