Effect of Natural Moringa Leaf Extract, Dry Yeast, and Potassium Thiosulfate on Thompson Seedless Grape cv. under Assiut Climatic Conditions

Numerous dual challenges place major limits on crop productivity and the long-term viability of farming systems in semi-arid regions. It is necessary to explore and implement agricultural strategies capable of enhancing the plant's ability to tolerate abiotic stresses. This study was conducted in the 2022 and 2023 seasons to investigate the effects of natural moringa leaf extract (MLE), dry yeast, and potassium thiosulfate on the vegetative growth, yield, and berry quality of grape cv. Thompson Seedless under Assiut climatic conditions, Egypt. Sprays consisting of water only (control), MLE at 3%, dry yeast at 1%, potassium thiosulfate at 1%, and MLE at 1.5% + dry yeast at 0.5% + potassium thiosulfate at 0.5% were sprayed three times on Thompson Seedless vines at growth beginning, after fruit set, and one month later. The results showed that foliar spraying of all studied treatments enhanced leaf area, chlorophyll content, pruning wood weight, yield, berry quality, and tolerance to abiotic stresses. The highest percentage of berry set (17.21%) and yield per vine (14.69 kg) were recorded by the combined treatment compared to the control, which produced the lowest value for berry set (15.6%) and yield (9.94 kg/vine). The combined treatment achieved the highest percentage of TSS at 21.47%, reducing sugar at 16.26%, and the lowest acidity at 0.301%, while the percentages in the control treatment were 19.07%, 14.84%, and 0.481%, respectively. Overall, the MLE 1.5% + dry yeast 0.5% + potassium thiosulfate 0.5% treatment was found to be the most effective that should be advocated, as it involves economical materials and eco-friendly practices.