Seo-Jun Park

Transcriptional analysis of Dehydrin1 genes responsive to dehydrating stress in grapevines

Dehydrins (DHNs) are proteins that are induced under dehydrating stress conditions such as drought, cold, and salinity. We investigated the expression of the DHN1 genes over time after drought treatment for 14 days and subsequent rehydration in the Korean native species, Vitis flexuosa, main cultivars ‘Campbell Early’ (Vitis spp.) and ‘Tamnara’ (Vitis spp.). Two highly homologous dehydrins, DHN1a and DHN1b, were isolated from ‘Campbell Early’ and ‘Tamnara’ grapevines, but only DHN1a cDNA was cloned from V. flexuosa leaves. Amino acid sequences of DHN1 deduced from five cDNAs of DHN1a/b from three grapevines were of the YSK2-type having the Y-, S-, and K-domain. Analysis of expression using quantitative real-time polymerase chain reaction and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) revealed that expression of the DHN1a and DHN1b genes was induced earlier in V. flexuosa under drought stress conditions than in ‘Campbell Early’ and ‘Tamnara’. During drought stress, a large amount of DHN1a and DHN1b was continuously expressed. V. flexuosa could be a resource in stress-tolerant grape breeding for enhancing drought tolerance.

Regional Differences of Leaf Spot Disease on Grapevine cv. `Campbell Early` Caused by Pseudocercospora vitis in Plastic Green House

Pseudocercospora leaf spot was major disease of grape cultivar `Campbell Early` in Korea. Leaf spot first appeared in early June and rapidly dispersed to other leaves through rainy season. Disease progress of leaf spot by Pseudocercospora vitis in plastic green house, in the two provinces (Gimje and Gimcheon), were investigated in 2007. Differences of Infected leaves (%) between cultivation systems were observed in field and plastic green house, but there was no difference between provinces. Micro environmental factors, such as temperature and relative humidity, were correlated with infected leaves by PROC REG procedure of SAS (Statistical Analysis System). As a result, regression model best described (

Prediction of Evapotranspiration from Grape Vines in Suwon with the FAO Penman-Monteith Equation

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Application of Color Index for Red Grapes (CIRG) for Assessment of Grape Quality

Food and Agricultural Organization (FAO) Penman-Monteith (PM) equation is one of the most widely used equations for predicting evapotranspiration (ET) of crops. The ET rate and the base crop coefficients (Kcb) of the two different grape vines (i.e., Campbell Early and Kyoho) cultivated in Suwon were calculated by using the FAO PM equation. The ET rate of Campbell Early was 2.41 mm day−1 and that of Kyoho was 2.22 mm day−1 in August when the leaf area index was 2.2. During this period, the Kcb of Campbell Early based on the FAO PM equation was on average 0.49 with the maximum value of 0.72. On the other hand, the Kcb of Kyoho was averaged to be 0.45 with the maximum value of 0.64. The seasonal leaf area index for two grape cultivars was measured as 0.15 in April, 0.5 in May, 1.4 in June, 2.2 in July-September, and 1.5 in October. The Kcb of Campbell Early showed a seasonal variation, changing from 0.03 in April to 0.11 in May, 0.31 in June, 0.49 in JulySeptember, and 0.33 in October. The magnitudes and the seasonality of Kcb of Kyoho were similar to those of Campbell Early.

Effect of cell wall degrading enzyme and skin contact time on the brewing characteristics of Cheongsoo grape

Hunter value (L*, a*, b*) is a rapid and convenience method for compare with different skin color, but not suitable to compare quality with various grape cultivars. Color Index for Red Grapes (CIRG) is one of a simply convert method for grape skin color as numeric data, and many previously result showed that high correlation between CIRG index and various quality factors of grape. In this experiment, we measured CIRG index, total soluble solids (TSS), titratable acidity (TA), and total anthocyanin content on the grapes (Campbell Early, Heukbosuk, Kyoho) from the varaison to harvest. As a result, CIRG index and anthocyanin contents have an exponential correlation; r-square is each 0.8595 in the ‘Campbell Early’ and 0.8500 in ‘Heukbosuk’. And TSS and CIRG index have a positive r-square, at the Campbell Early is 0.7758 and Heukbosuk is 0.7253. Also TA and CIRG index have a positive r-square, at the Campbell Early is 0.7279 and Heukbosuk is 0.6630. These results were shown that CIRG index is a reliable indicator for a none-destructive evaluation of the grape quality. Additional key words : color space, colorimeter, regression analysis