Effect of foliar spraying with Seaweed Extract (Chlorella vulgaris) and Nano fertilizers on growth, yield and fruit quality of Flame Seedless grapevines

The present study was conducted during three successive seasons 2020, 2021, and 2022 on thirty-six uniform 6-year-oldFlame seedless grapevines, in a Private vineyard in Gohaina region, Sohag, Egypt. This study examined how grapevines respond physiologically, in terms of growth, yield, and quality, to Hydrogen Cyanamide and seaweed extract (Amphora coffeaeformis) as dormancy breaking, as well as Chlorella vulgaris, Nano fertilizers (nano Fe+ Zn), and conventional fertilizers (EDTA Fe + Zn) applied three times at on the same vines at fruit set, berry size 6:8 mm and at veraison stage as single or combined.The highest value of growth and yield parameters and chemical characteristics were recorded to combined application of (Hydrogen Cyanamide) dormix 5% 1stweek of Jan.× Chlorella vulgaris at 1ml/l and (nano Fe + Zn)1ppm(as an average of the three studied seasons) aspects than using each material alone. It is concluded that the foliar combined application Hydrogen Cyanamide 5% 1st week of Jan. once and Chlorella vulgaris at 1ml/l and (nano Fe + Zn) 1ppm applied three times on the same vines at fruit set, berry size 6:8 mm and at veraison stage led to clear enhancements in the majority of the tested vegetative and fruiting parameters of Flame seedless grapevines.