الفهرس 
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Abstract
The current study was carried out during two successive seasons 2018 and 2019 on 28 years old grapevines of Ruby seedless cultivars. Grown in loamy clay soils in a vineyard at the experimental Orchard of Pomology, Faculty of Agriculture, Assiut University. The selected vines trained according to the bilateral cordon system. The vine were pruned leaving 36 buds/vine.
The chosen 72 vines were divided into nine different treatments including the control (sprayed water only), four replicates, one vine each.
One of the selected group vines were sprayed at the 1st time with 1sttimes of each treatment. The first spray was (at pre-bloom, when shoot length) was apportmetally 20 cm and the vines of the second group were sprayed at the 2nd time (after fruit set when the berry size reached 6 mm) during the two studied seasons.
Harvesting was carried out at the normal commercial harvest date of grapes.
The obtained results of this study could be summarized as follows:
1- Yield Weight(kg/Vine)
All treatments using jasmonic oil and coffeic acid and their mixture showed asignificant increase in yield weight (kg) / vine during the two studied seasons.
2- Bunch Weight(g)
The obtained results showed that all treatments of this study induced a significant increase in bunch weight compared to the untreated vines (control) in the two examined seasons.
As for the mixture of jasmonic oil and coffeic acid results indicated that spraying a mixture of 6 cm3/L jasmonic oil + 30 ppm coffeic acid at the 1st or 2nd application time gave the heaviest bunch weight, compared to untreated vines in the two studied seasons.
3- Rachis weight (g)/ Bunch
Concerning the recorded results of this study, it was clear that spraying 6 cm3/L jasmonic oil was very effective at the 2nd time rather than the other treatments, while using a mixture of 3 cm3/L jasmonic oil + 30 ppm coffeic acid at the 1st time induced the heaviest rachis weight. On other side, spraying 6 cm3/L jasmonic oil at the 2nd time was more effective on rachis weight than the other treatments, all results were compared to untreated (control) vines during the two studied seasons.
4- Bunch length (cm)
The results showed that, at 1sttime of both two studied seasons that spraying a mixture of jasmoninc oil and coffeic acid (6 cm3J + 60 ppm C) gave the highest value of bunch length, while the most of treatments induced a significant reduction of bunch length.
The best results for bunch length characteristic, was obtained from spraying the mixture of jasmonic oil and coffeic acid at a concentration (3cm3J+ 30 ppm C) at the two application times, compared to other treatments and untreated vines through the two studied seasons.
5- Weight and volume of 100 berry
According to the obtained results of this study, it was noticed that, all treatments at the 1st or 2nd time improved both of weight and volume of 100 berry, compared to untreated (control) vines during the two studied seasons.
Moreover, spraying 60 ppm of coffeic acid or a mixture of 3 cm3/L jasmonic oil + 30 ppm coffeic acid at the 2nd time gave the highest value of both weight and volume of 100 berry compared to other treatments through the two seasons.
6- Weight and volume of 100 berry juice
The results showed that, there was a significant increase in the weight and size of 100 berry juice during the two studied seasons.
Furthermore, it was found that spraying jasmonic oil (at 3 or 6 cm3/L) at the 1st or 2nd time showed more effective on these parameters compared to coffeic acid.
On the other hand, spraying mixture of jasmonic oil plus coffeic acid (3 or 6 cm3/L + 60 ppm, respectively) at the 2nd time resulted in the highest value of both weight or volume of 100 berry juice, compared to untreated vines during the two seasons of this study.
7- Total soluble solids (T.S.S%)
All treatments with jasmonic oil, coffeic acid and their mixture exhibited significant increase in T.S.S% in grape juice compared to untreated vines in the two studied season.
Moreover, it was found that spraying 60 ppm coffeic acid at the 1st time gave the highest TSS% in grape juice during the two studied seasons, while spraying 30 ppm coffeic acid sprayed at the 2nd time induced the highest TSS% in grape juice during the 1st season as well as spraying a mixture of 6 cm3 jasmonic oil plus 60 ppm coeffeic acid at the same time exhibited the highest TSS% in grape juice in the 2nd season.
8- Titratable acidity% (T.A%)
The obtained results indicated that there was a significant increase in TA% in grape juice in response to all the treatment during the two studied seasons.
Furthermore, it was demonstrated that spraying a mixture of 6 cm3/L jasmonic oil plus 60 ppm coeffeic acid at the 1st time gave the highest TA% and spraying 6 cm3/L jasmonic acid at the 2nd time gave the highest TA% in grape juice during the 1st season.
On the other hand, spraying 60 ppm coffeic acid at the 1st time gave the highest TA%, while spraying the two concentration of coffeic acid at the 2nd time gave the highest TA% in grape juice during the two seasons, all treatments compared with untreated vines.
9- TSS/acid ratio in juice
The obtained results showed that, all treatments induced a significant decrease in TSS/TA ratio in grape juice, compared to untreated vines under the condition of this study.
Generally, it was noticed that, spraying a mixture of 6 cm3/L jasmonic oil plus 60 ppm coffeic acid at the 1st time gave the lowest TSS/TA ratio, while spraying 6 cm3/L jasmonic oil at the 2nd time gave the lowest TSS/TA ratio in the 1srt season.
During the 2nd season, spraying a mixture of 3 cm3/L jasmonic oil plus 30 ppm coffeic acid at the 1st time resulted in the lowest TSS/TA ratio, while spraying 6 cm3/L jasmonic oil at the 2nd time gave the lowest TSS/TA ratio in grape juice, all treatments were compared to untreated vines.
10-Total sugar%
The recorded data deduced that, all treatments induced a significant increase in total sugar % compared to untreated vines during the two seasons.
Hence, it was found that spraying 60 ppm coffeic acid at the 1st time gave the highest percentage of the total sugar, while spraying the lowest concentration of the coffeic acid at the 2nd time exhibited the highest total sugar % compared to the untreated vines during the 1st season.
As well as, spraying 60 ppm coffeic acid at the 1st time gave the highest percentage of total sugar, while spraying a mixture of 6 cm3/L jasmonic oil + 60 ppm coffeic acid at the 2nd time resulted in the highest percentage of total sugar in grape juice through the 2nd season.
11- Reducing suger %
As shown from the obtained results, it was noticed that, treatment with both of jasmonic oil, coffeic acid and their mixtures induced an increase in reducing sugar % in grape juice, with insignificant increase between the two application times during two studied seasons.
Although, spraying 60 ppm coffeic acid at the 1st time gave the highest percentage of reducing sugar, while spraying 30 ppm coffeic acid at the 2nd time resulted in the highest reducing sugar % during the 1st season.
On the other side, spraying a mixture of 6 cm3/L jasmonic oil + 30 ppm coffeic acid gave the highest value of reducing sugar % and spraying a mixture of 3 cm3/L jasmonic oil + 30 ppm coffeic acid at the 2nd time gave the highest reducing sugar % in grape juice, all treatments compared to untreated vines during the 2nd season.
Recommendation:
Therefore, according to the obtained results under the condition of this study,hence, the conclusive recommendation is spraying a mixture of both jasmonic oil plus coffeic acid at the 1st and the 2nd application times to improve both of yield weight and berry quality of Ruby Seedless grape cultivar.