Growth And Yield Responses of Apple Cultivars to Organic Manure and Plant Extracts

This study investigated the influence of organic manure and nettle plant extract at three concentrations on the vegetative and yield characteristics of the Starking, Granny Smith and local apple cultivar during the 2024 growing season at a private orchard in Duhok government, Iraq. Foliar spraying was conducted on the 25th of April and May, 2024. A factorial randomized complete block design with three replications was used. Statistical analysis using SAS software with Duncan's multiple range test (p≤0.05) revealed significant cultivar-specific responses. The Granny Smith cultivar demonstrated superior performance in vegetative parameters, exhibiting 97.6% greater leaf area (90.92 cm² against. 47.32-47.48 cm²), 12.1% higher leaf chlorophyll content (28.38 mg·g⁻¹), and 64.5% greater yield (183.33 kg·tree⁻¹) compared to the Starking and local cultivars. The optimal treatments (4 mL·L⁻¹ organic manure + 200 mg·L⁻¹ nettle extract) significantly enhanced various physiological and yield parameters for leaf area (+97.6%), fruit peel chlorophyll (+67.2%), total soluble solids (19.67%), and anthocyanin content (98.82% in Starking), while reducing fruit acidity by 30.4% in the Granny Smith. These findings show that integrated organic amendments can effectively improve apple productivity and fruit quality, with cultivar-specific responses highlighting the importance of genotype selection in sustainable orchard management systems