Aquaponic production of strawberries: Influence of boron and media on their mineral and sugar composition

Abstract

Abstract Strawberries can fetch high market prices, but this is often based on their sweetness. Previous studies have shown that sugar content in fruits is elevated by boron (B), but this has not been tested on strawberries in an aquaponic system. In this study, strawberries were aquaponically cultured with or without B supplementations and with or without media (2 × 2 factorial design) over 2 months. Each of the six identical aquaponic units contained 30 catfish juveniles (initial weight = 2.1 g) and two plant culture units; one with a floating raft (without media) and one with expanded lava rock (with media). Borax was the source of B, which was weekly added at 0.01 mg/L. Water quality and fish growth were unaffected by B additions. Total number of strawberries and their total weights were unaffected by B or media. Media caused strawberries to be individually heavier with higher sodium, iron and moisture but significantly less glucose and fructose. Supplementations of B significantly increased and decreased the B and zinc content of strawberries, respectively, as well as causing significantly shorter roots. Growing strawberries with or without media in an aquaponic system provided different advantages but B supplementations appeared unnecessary and may have caused some toxicity to the strawberries.

Keywords

• boron
• Fragaria x anannassa
• root length
• sugar composition