الفهرس 
INTODUCTIONOnly 14 pages are availabe for public view
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Abstract
Grapes are considered one of the most important fruit crops in the world. The discoloration and the decreasing of grape quality and postharvest characteristics of grapes all over the world. These negative characteristics increased during the last decades after the global worming effects have been increased. The use of some compounds such Ethrel to increase the grape quality characteristics has become a vital factor between growers and producers of grapes. Girdling is one of the most important horticulture practices and especially on fruit trees. It improves the carbohydrate accumulation in the branches. Thus improve the quality of the fruits. It improved some characteristics related to the quality and color. The finding of alternatives of these substances still gaps of knowledge.
The impact of some organic compounds and gridling as an agricultural practice on grapes quality, productivity, and storage characteristics were studied in this thesis. These organic compounds were two amino acids and two polyols (sugar alcohols) compounds. The study attempted to find alternatives to Ethrel® (Ethephon) for berries coloration, other clusters and berries quality and quantity characteristics. In addition, the clusters were stored in a cooler for 21 days as a transit cooling stimulation of transportation cooling storage, then some main characteristics related to the postharvest losses were investigated per intervals.
The Experiment was designed in a Split plot design (SPD), and one hundred uniform vines were used (20 treatments x 5 replicates x one vine/replicate) in a factorial experiment. The 20 treatments were divided into 2 main groups; girdled vines and non-girdled vines (main plots). Each one of 10 treatments (submain plots) comprised foliar application of water (control), Ethrel® (Ethephon) at 480 ppm, polyols (Sorbitol and Mannitol) at 10 and 20 mM, and Amino acids (phenylalanine and methionine) at 250 and 500 ppm.
The experiment was carried out on a vineyard located at the Cairo-Alexandria desert road for two successive seasons 2017 and 2018 on 10-year-old Crimson seedless grape cultivar (Vitis Vinifera L.) grown in sandy soil. They were normally irrigated under drip irrigation, fertilized, and trellised by Spanish Barron training system. Vines were spur pruned and spaced at 3×4 m between vines and rows respectively.
The foliar application of Ethrel, Polyols and amino acids was applied two times at the veraison stage by using a back-carrying sprayer. The first time when at the beginning of verasion stage. The second application was done after two weeks of the first application. The girdling was done before the veraison stage at the trunk (main stem).
The clusters were collected at the full maturity stage with the common grape maturity indices. The samples of clusters were collected in the last week of July and were divided into two groups, one of them for the physical and chemical measurements and the other group stored in a cooler for 21 days, and postharvest measurements were recorded. The Pre-harvest measurements before the storage period were physical and chemical criteria. For physical criteria the study measured cluster weight/g, yield/vine/kg, cluster width (cm), weight of 100 berries (g), cluster length (cm), berry length (mm), berry width(mm), brush length (cm), pedicel length (mm), tours width (mm), detachment force (g) and Firmness of berries Kp/cm2. For chemical criteria the study measured the total soluble solids (TSS as Brix°), titratable acidity (TA) g/100ml, TSS/ acid ratio was calculated subsequently. In addition to, skin color % which was evaluated by the color charts, and the anthocyanin (mg/100g).
Then Number was stored at 0°C±2 and RH 85-90 % for 21 days as a storage period and then the following criteria were measured as a postharvest characteristic: excluded clusters %, dropped berries %, shrunken berries %, rotten berries %, cluster, weight changing %, changing in TSS % beside the interval of these criteria per each week approximately.
The results showed that girdling significantly increased the color, anthocyanin content of the berries, the length and width of clusters, firmness, and detachment force. On the contrary it did not have any significant effect on weight of clusters, yield weight/ vine, weight of 100 berries, Total soluble solids TSS, Titratable acidity (TA), TSS/Acid ratio, length and width of berries, tours width, pedicel length, brush length. In addition, it did not have any significant impact on the entire postharvest characteristics.
The results of the foliar application of amino acids and sugars alcohol showed that sorbitol in 10 and 20 mM solo or with the girdling significantly affected the length and width of clusters. Phenylalanine in 250 and 500 ppm had significance of weight of 100 berries, brush length, pedicle length, tours width, detachment force, firmness, acidity, anthocyanin content. in addition, it had effect on the reduction of postharvest losses of clusters and berries such as shrunken berries %, excluded clusters %, rotten berries, dropped berries %, weight loss %, changing in TSS. The other treatments but not the ethrel participated in the effect on decreasing the excluded clusters %, and the rotten berries. Mannitol in both 10 and 20 mM had the highest means of TSS. Besides, there were a variation between treatments in effect of the dimension of berries as length and width of berries. The methionine 250 and 500 ppm shared the significant difference on firmness and detachment force with phenylalanine.
The ethrel treatment had the highest significant values in the undesired postharvest characteristics such as shrunken berries %, excluded clusters %, rotten berries, dropped berries %, weight loss %, changing in TSS.
In conclusion the girdling affected many grape qualities related with the firmness and coloration of clusters and berries characteristics. Phenylalanine and methionine played roles in increasing detachment forces and firmness which consequently appeared in the storage period and decreased the losses and increased the quality. Phenylalanine showed significant differences in most of the treatments. The effect of treatments on weight of clusters and total weight was not clear. There was a combination effects of girdling with the used organic compounds on various characteristics. all the treatments reduced the postharvest losses compared to the ethrel treatment.