Optimizing bent branch numbers improves transpiration and crop water productivity of cut rose (Rosa hybrida) in greenhouse

Abstract

Bent branches are commonly utilized in cut roses to enhance commercial flower quality through increased nutrient production and biomass. However, the ideal number of bent branches concerning crop water productivity remains unknown. The experiment was conducted in Jinning, Yunnan, in 2022 with total of three growth periods with 1–3 bent branches. Sap flow of a commercial branch was measured using the heat ratio method to assess rose transpiration and crop water productivity during each growth period. Across three harvests, cut roses with three bent branches increased plant height by 87.9% compared to those with one bent branch (217 cm). The Fresh weight of cut roses with three bent branches was 63.6 g shoot−1, 135% more than with one bent branch. The roses with three branches produced 56% more high-grade (grade A and grade B) shoots than in other treatments. Daily transpiration in roses with three bent branches was 4.09 mm d−1 across three harvests, which was 115% higher than in one bent branch. The economic value in three bent branches was 54% higher than in two bent branches and 120% higher than in one bent branch. Crop water productivity in three bent branches across three periods was 14.7 kg m−3, which was 84.7% higher than in two bent branches and 167% than in one bent branch. Our results help farmers to optimize irrigation of cut rose in greenhouse conditions and could be used in improving rose models by quantifying transpiration at crop level.

Keywords

• Bent branches
• Heat ratio method (HRM)
• Flower quality
• Sap flow
• Sap velocity