Sustainable production of greenhouse ornamentals using plant growth-promoting bacteria

Greenhouse ornamentals are produced with high rates of water-soluble fertilizer to accelerate flowering and reduce the time to market-ready crops. Many of the applied nutrients are not utilized by the plant and are leached from containers, contributing to environmental pollution. Plant growth-promoting bacteria (PGPB) can be used to increase nutrient use efficiency and improve the sustainability of ornamental crop production. Identifying PGPB that will interact with the hundreds of genera and species of ornamental plants is a daunting task that is limited by the space and time required to conduct rigorous greenhouse trials to quantify growth promotion and identify the positive health effects of treatment with PGPB. Digital phenotyping using systems like the TraitFinder with PlantEye sensors provides solutions to this bottleneck that will allow for high throughput screening of PGPB in planta. Petunia × hybrida ‘Carpet Red’ plants were treated with Bacillus amyloliquefaciens QST 713, and plant growth and health were compared between treated and untreated control plants using traditional manual measurements and digital measurements from the TraitFinder. Digital biomass was found to be a more accurate representation of plant growth than the growth index. Manual measurements were positively correlated with digital measurements, with the growth index showing the strongest correlation with digital biomass, plant height, and 3D leaf area. NDVI was a more accurate estimator of chlorophyll content than the SPAD meter. Digital phenotyping will help us efficiently screen PGPB to identify those that will improve nutrient use efficiency and reduce the environmental impacts of ornamental plant production.