2019 ASHS Annual Conference

A pot study was conducted to investigate the effects of individual biostimulants on tomato (cv. ‘Phoenix’) growth and yield in greenhouse in fall 2017. Six different biostimulants: CP₁, CP₂, BS, CP₂+BS, Competitor, and Water (control) were respectively foliar-applied at three different stages: pre-bloom, fruit setting and color change. A control (only water sprayed) was paralleled. The contents of Ca, K, Mg and P in leaves and roots were also determined. Plants treated with biostimulants improved the levels of Ca, K, Mg and P compared to those treated with water only. Competitor and CP₂+BS among the six significantly increased yield, plant dry biomass (PDB), plant height, stem diameter, leaf greenness (SPAD reading), photosynthetic rate (Pn), relative water content (RWC), nitrate level in petiole sap, and fruit quality (citric acid, malic acid, tartaric acid, soluble solid concentration and fruit firmness). In addition, enzymatic activities of nitrate reductase (NR) and nitrite reductase (NiR) were increased by the biostimulants. Competitor and CP₂+BS showed the greatest augmentation in plant biomass, plant height, stem diameter, leaf greenness, Pn, RWC, nitrate level in petiole sap, fruit yield and quality. NR, NiR, Ca, K, Mg and P showed a similar trend. Application of Competitor or CP₂+BS may potentially become a BMP tool for tomato production but more trials are needed for large scale field demonstration.