Heat stress has always been a major determinant of mandarin production in Upper Egypt. To reduce the negative effects of such climatic changes on the mandarin trees in Assiut, proline was used to make the trees able to withstand these changes. Herein, the experiments were executed throughout two successive seasons (2019/2020 and 2020/2021) at the experimental orchard of Assiut University, Faculty of Agriculture, Egypt, on twelve uniform Balady mandarin trees in a complete randomized-block design (3 treatments x 4 replications). The main objective of this study was to enhance the fruit quality of the Balady mandarin cultivar by using different concentrations of L-proline (100 and 200 µg/ml) under Assiut conditions. Balady mandarin trees were exposed to L-proline five times through the fruit-growing period (every 30 days from June 1st week to October 1st week). The results demonstrated that five applications of 200 µg/ml L-proline foliar treatment might significantly boost Balady mandarin quality. Consequently, using this eco-friendly fertilizer under the climatic conditions of Assiut is recommended.

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 (CaCl2), potassium nitrate (KNO3), and flower thinning on reducing these problems and enhancing fruit quality. Seven treatments were carried out, including foliar application with CaCl2 2 and 4%, KNO3 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 KNO3 or 4% CaCl2 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.

Currently, nanotechnology is widely used in agriculture and horticulture. Nanofertilizers are essential for encouraging vegetative growth and flowering, as well as enhancing productivity and fruit quality. These nanoparticles are viewed as growth promoters as well. The current study was therefore carried out during the two successive seasons of 2021 and 2022 on 14-year-old trees grown in clay soil in a field experiment at the Pomology Department Research orchard, Faculty of Agriculture, Assiut University, Egypt. The effects of conventional vs. nano-micronutrients as foliar fertilizers on the fruit yield, quality, and mineral nutrition status of pomegranate trees were studied. The foliar application of all treatments on pomegranate trees remarkably increased yield and physical properties of fruits as well as improved the levels of total soluble solids percentage, anthocyanin pigment, flavonol, total phenols, antioxidant activity and nutrients status compared with the controls during the 2021 and 2022 seasons. The lowest fruit cracking percentages were obtained by the spraying of nano-micronutrients (4.33–5.70 %) compared with the other treatments and the control, which gave the highest percentages (10.45–11.43 %). The highest increments in yield, physical properties of fruits and levels of total soluble solids percentage, anthocyanin pigment, flavonol, total phenols, and antioxidant activity were noticed by the spraying of nano-micronutrients especially at 1000 and/or 1500 µg mL⁻¹. It could be concluded that the use of nanofoliar fertilization in pomegranate cultivation may improve the yield, quality, and nutritional status of pomegranate fruits.

Penicillium digitatum Sacc is a common postharvest pathogen affecting lime fruits. It causes significant losses in postharvest lime production. An emerging alternative to chemical control is the use of environmentally friendly such as edible and biodegradable films and packaging. The goal of the current study was to test different concentrations of Aloe vera gel (5, 15, 25, 50, 75, and 100% v/v), tea tree oil coating (0.5, 1, 2.5, 5, and 10% v/v), and their combination for controlling P. digitatum in vitro. The results revealed that specific concentrations of Aloe vera gel (75% and 100% v/v), tea tree oil (2.5, 5, and 10% v/v), and Aloe vera gel (25%) + tea tree oil (1%) v/v showed the highest inhibitory effect against the pathogen. The most effective concentrations of Aloe vera gel (75%), tea tree oil (2.5%), and Aloe vera gel (25%) + tea tree oil (1%) were evaluated against the green mold disease of lime under natural infection through storage period (0, 7, 14, 21, and 28 days). Compared to the control group, all edible layers demonstrated a significant delay and reduced in disease severity percentage throughout the storage periods. However, coating lime fruits with a combination of Aloe vera gel (25%) + tea tree oil (1%) successfully prevented the green mold disease of lime fruits over 28 days. The impact of these coatings was evaluated on lime fruit quality maintenance (weight loss, firmness, juice weight, total soluble solids, total acidity, pH, vitamin C, lipid peroxidation content, total phenols, total flavonoid, and total protein) over 28 days of storage during the 2021 and 2022 seasons. All treatments improved fruit quality through the storage period compared with untreated fruits. Treated lime fruits with Aloe vera gel (25%) + tea tree oil (1%) exhibited slight reductions in weight loss and juice weight compared to alternative treatments as an average of the two successive seasons. Simultaneously, this treatment improved fruit firmness, vitamin C levels, total phenols, total flavonoid, and total protein when contrasted with other treatments as an average of the two studied seasons. These findings show that the combination of Aloe vera gel and tea tree oil coatings enhances the shelf life and maintains the quality of lime fruits. They can also be used as an environmentally acceptable, chemical-free alternative treatment to preserve the postharvest quality of lime fruit.