Search

The current investigation represents of the synergistic effects of application of potassium nitrate (KNO3) in combination with putrescine (Put) on flowering, productivity, and fruit quality on Ewais mango (Mangifera indica L.) trees during the seasons 2021/2022 and 2022/2023. The selected trees were sprayed at three different stages, including flower bud differentiation, full bloom, and beginning of the fruit set, with one of the following treatments: control, 2% KNO3, 4% KNO3, 50 ppm Put, 75 ppm Put, 2% KNO3 + 50 ppm Put, 2% KNO3 + 75 ppm Put, 4% KNO3 + 50 ppm Put, 4% KNO3 + 75 ppm Put. Results showed that all treatments were successful in improving the productivity of mango trees by increasing flowering terminal shoots, fruit set, fruit retention, number of fruits/tree, yield, and fruit yield increment while reducing the percentage of fruit drop, as well as improving the quality of mango fruits cv. Ewais by increasing fruit length, fruit diameter, TSS, total sugars, V.C, and total phenol and carotenoid content, but at the same time, diminishing the total acidity, as compared with control. Based on this research, the application of 4% KNO3 in conjunction with 75 ppm Putrescine has shown the most prominent advances in enhancing Ewais tree productivity and fruit quality. The investigation successfully highlighted the synergistic effect of using KNO3 and putrescine to improve mango fruit yield and quality.

The effect of foliar spray with algae extract and/or potassium nitrate on the quantity and quality of Barhee date palm yields was investigated during the 2017 and 2018 seasons. Inflorescences of Barhee date palms were sprayed twice, after pollination (1st April of each season) and one month later, with algae extract at concentrations of 0.5% and 1.0% and with potassium nitrate at concentrations of 1% and 2% applied individually or in combinations. The obtained results showed that all of the sprayed treatments enhanced the yield and fruit properties when compared to the controls. Spraying inflorescences of Barhee date palms with algae extract and/or potassium nitrate had a significant effect on the yield and on the physical and chemical properties of the fruit when compared with the untreated palms. The increase in yield and qualitative properties was associated with increasing concentrations of both materials (algae extract and potassium nitrate). The best results were detected with spray containing high rates of combined treatment (1% algae extract + 2% potassium nitrate) applied twice in both seasons studied because this treatment resulted in the highest value of fruit and bunch weight, increased the yield per palm compared to the control by about 60.2%, and improved the fruit physical properties (fruit length, fruit diameter, fruit shape index, flesh weight, and seed weight) and fruit chemical properties (total soluble solids (TSS); acidity; TSS/acid ratio; tannins; and reducing, nonreducing, and total sugars) of the Barhee date palm given the experimental conditions.

The influence of salicylic acid (SA) on growth, yield, fruits’ quality and enzymes’ activities was monitored in strawberry plants cv. Camarosa grown under salinity stress via two pot experiments in two successive years of 2018 and 2019. The examined concentrations of SA were 30, 60, and 90 ppm, which foliary applied in addition to control (sprayed with water), while the used levels of salinity were 20, and 40 mM as NaCl as irrigation application in addition to control (without salinity). The results showed a significant effect of salinity at 40 mM where the mean values of shoot fresh and dry weights, chlorophyll, leaves’ NPK, yield plant−1, yield ha−1, and fruits’ ascorbic acid were significantly decreased. However, the 40 mM salinity resulted in a significant increase in leaves’ content of Na and proline as well as catalase (CAT) and peroxidase (POD) enzymes’ activity and the fruits’ TSS and acidity. The application with 90 ppm SA was found to be the most significant positive treatment for all of the studied characters except the Na leaves’ content. Regarding tolerance index percentages (STI%), the high values of CAT, POD, and proline referred to the ability to use them as indicators for strawberry salinity response in other physiological and plant breeding studies. The findings of this study suggest that the 90 ppm SA foliar application can ameliorate the negative effect of salinity on the growth of strawberry cv. Camarosa.