Plant growth promoting rhizobacteria combined with macronutrients treatments improve growth and market quality of cut sunflower (Helianthus annuus L.)

Abstract

Cut sunflower represents a significant cut crop within Pakistan's floriculture sector, benefiting from favourable agro-climatic conditions. However, the visual quality of ornamental plants has an essential association to a proper balance of nutrients. Qualitative aspects such as plant height, shape, and colouration are directly affected by mineral nutrition, along with various environmental factors. Recently plant growth promoting rhizobacteria (PGPR) combined with appropriate macro and micronutrients promising approach to enhance the growth and quality of ornamental plants. The significance of cut sunflower in the cut market is noteworthy. Therefore, this study was executed to improve the growth and maintain the market quality of cut sunflower cv. ‘Vincent’ by using various PGPR and macronutrients concentrations with control viz. T0: Control, T1: NPK (20: 20: 20), 60 g/m² bed, T2: Bacillus spp., T3: Pseudomonas spp., T4: PGPR injection, T5: Bacillus spp. + NPK (20: 20: 20), 60 g/m² bed, T6: Pseudomonas spp. + NPK (20: 20: 20), 60 g/m² bed, T7: PGPR injection + NPK (20: 20: 20), 60 g/m² bed. The application of Bacillus spp. + NPK (20: 20: 20), 60 g/m² bed, Pseudomonas spp. + NPK (20: 20: 20), 60 g/m² bed, PGPR injection + NPK (20: 20: 20), 60 g/m² bed resulted in higher flower visual quality, plant height, leaf area, stem diameter, flower diameter, blooming period, plant fresh and dry weight compared to control treatment. Among studied treatments Pseudomonas spp. + NPK (20: 20: 20), 60 g/m² bed exhibited higher plant nitrogen, phosphorous, potassium, organic matter and organic carbon contents. In conclusion, PGPR combined with macronutrients treatments effectively improves the growth attributes and maintains the market quality of cut sunflower cv. ‘Vincent’.