Experiment was carried out throughout two successive seasons of 2016 and 2017 on Flame Seedless, Ruby Seedless and Thompson Seedless grapevines grown at the Experimental Orchard of Assiut University, Faculty of Agriculture. The aim of this study was to assess the impacts of abscisic acid (ABA), cluster thinning and their combinations with GA 3 on yield weight of three important grape cultivars grown under hot region. Data revealed that, the application of abscisic acid (ABA) increased yield weight (kg/vine), while cluster thinning decreased it. During the 1 st season of study (2016), all individual ABA treatments and ABA at 400 ppm combined with GA 3 at 10 ppm significantly increased yield weight (kg/vine) comparing with the control treatment. As a result of ABA treatments at 200, 400 and 600 ppm and ABA at 400 ppm plus GA 3 at 10 ppm, the yield was increased by 15.5%, 10.5%, 9.8% and 9.2%, respectively. During the 2nd season of study (2017), only ABA at 600 ppm treatment significantly surpassed the control treatment with an increment percentage of 20.5%. The rest of treatments either had no effect or reduced the yield weight comparing with the control. On the other side, cluster thinning by removing 30% of the total clusters that the vine bearing significantly reduced the yield weight (kg/vine) during the two studied seasons. As a result of such treatment, the yield was reduced by 37.2% and 39.2% in 2016 and 2017 seasons, respectively.

One of the major issues with pomegranate production in arid and semi-arid climate is the white arils of fruit. The known plant regulators abscisic and jasmonic acids play a variety of roles in plant growth and the reduction of abiotic stresses. However, little is known about their application to improve the quality of pomegranate fruit, particularly white arils, in semi-arid environments. Herein, the experiments, in this study, were performed in two consecutive seasons 2020 and 2021 on 10-year-old Wonderful pomegranate trees to spotlight the improvement of the aril coloration and fruit quality by spraying with abscisic and jasmonic acids under semi-arid climatic conditions. Fifteen Wonderful pomegranate trees were subjected to five treatments (three replications for each). The tested treatments included abscisic acid (ABA) at the concentrations of 600 and 800 µg−1 mL, jasmonic acid (JA) at the concentrations of 10 and 15 Mm, and the control treatment (distilled water). The physical and chemical characteristics of the fruit quality of Wonderful pomegranate improved significantly when the trees were treated with abscisic or jasmonic acids. The foliar addition of ABA at 600 and 800 µg−1 mL increased the anthocyanin index by 96.74 and 114.75%, respectively, in the first year and by 49.48 and 67.62% in the second year, in comparison with the control. The foliar addition of ABA at 800 µg−1 mL was more effective than jasmonic acid in enhancing most of the chemical fruit properties, especially the anthocyanin index. The high level of ABA (800 µg−1 mL) gave the minimum fruit acidity and the highest fruit quality. Abscisic acid induces the fruit acidity and enhances the aril coloration in Wonderful pomegranate. In semi-arid conditions, it is recommended to spray the Wonderful pomegranate trees with abscisic acid at 800 µg−1 mL to improve the fruit quality and to increase the aril coloration.

This investigation was implemented during two successive seasons (2020 and 2021) on Ruby Seedless grapevines cultivated at the Experimental Orchard of Assiut University, Faculty of Agriculture. This work was designed to investigate the effectiveness of Ascorbic, Citric, and Abscisic acids on yield and anthocyanin concentration in the Ruby Seedless grape cultivar under Assiut climatic conditions. The obtained results revealed that all the treatments significantly increased the total yield/vine as compared to the control (untreated vines). Importantly, the highest yield weight was acquired from the Ascorbic acid (AA) at 600 ppm + Citric acid (CA) at 600 ppm + Abscisic acid (ABA) at 600 ppm treatment. In addition, the treatment of AA at 600 ppm + CA at 600 ppm + ABA at 600 ppm gave the highest value of anthocyanin content.

Pomegranate growers in Egypt have been struggling with a variety of production issues, including splitting, sunburn, and a lack of proper colour intensity and consistency, which are major barriers to attaining high quality fruit. The current research aims to evaluate the impacts of calcium chloride (CaCl 2 ), potassium nitrate (KNO 3 ), and flower thinning on reducing these problems and enhancing fruit quality. Seven treatments were carried out, including foliar application with CaCl 2 2 and 4%, KNO 3 250 and 500 ppm alone or combined with flower thinning and control (spraying with water). The spraying treatments took place three times, at the beginning of flowering (in Apr.), after fruit set completion (first Jul.), and before harvest (first Sept.), during the two study seasons. Hand flower thinning was done to all of the flowers that surged from the last week of May until the end of the flowering period. The obtained results indicated that spraying 500 ppm KNO 3 or 4% CaCl 2 alone or combined with flower thinning are regarded as the best treatments in terms of their impact on the yield components, fruit quality, anthocyanin content, and reducing fruit cracking.

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