Nitrogen Rates Reduce Phytochemical Content in Peach Fruit

Subtropical peach (Prunus persica L.) production helps growers to secure a unique market niche with early fruit production, commanding a premium price. This is particularly attractive for growers in Florida, considering the spread of Huanglongbing (citrus greening), which is severely affecting both acreage and economic returns. However, fertilization practices cannot be transferred from an evergreen tree such as citrus to a deciduous system, as with peach. Fertilization practices, particularly for nitrogen must be optimized for growing regions with significant summer rainfall to prevent unwanted leaching, without sacrificing fruit quality. Thus, the objective of this project was to identify key nitrogen rates for ‘TropicBeauty’ and ‘UFSharp’ for optimal fruit growth and quality, particularly flavonoids, phenolic content, anthocyanins, and antioxidant activity. Additionally, the impact of harvest time on phytochemical content was determined for ‘TropicBeauty’. An overall increase in total phenolic content (TPC), total flavonoid content (TFC), total anthocyanin content (ATC), and total antioxidant activity (TAC) occurred with decreasing nitrogen rates in both cultivars. A stronger genotype*nitrogen treatment interaction was observed in ‘TropicBeauty’ for TPC, TFC, and TAC. Overall, our data suggests nitrogen rate and harvest time plays an important role in harvested fruit attributes and therefore, can be strategically manipulated to satisfy consumer demand.