Rose bush leaf and internode expansion dynamics: analysis and development of a model capturing interplant variability

Area of Science:

• Horticultural science
• Plant physiology
• Agricultural engineering

Background:

• Rose bush architecture significantly impacts commercial visual quality, with high interplant variability posing a challenge.
• Individual organ expansion, a key architectural feature, remains understudied in rose bushes.
• Understanding and modeling this variability is crucial for optimizing crop production and quality.

Purpose of the Study:

• To investigate the expansion kinetics of primary shoot organs in rose bushes.
• To develop a model that simulates organ expansion, accounting for interplant variability.
• To utilize non-destructive input variables for accurate crop simulation.

Main Methods:

• Recorded changes in leaflet and internode dimensions over thermal time for 83 rose bush primary shoots.
• Developed an empirical model simulating organ expansion as a logistic function of thermal time.
• Evaluated the model using cross-validation, focusing on parameters like expansion time and rate.

Main Results:

• The model accurately simulated leaflet and internode expansion for individual plants (RMSEP = 7.3% and 10.2% of final length).
• Interplant variability in expansion kinetics was primarily due to differences in timing and rate, not duration.
• Model parameters related to expansion duration were consistent across plants, while final size and timing captured variability.

Conclusions:

• This study provides the first model to simulate organ expansion in rose bushes, effectively capturing interplant variability.
• The developed model defines essential measurements for simulating rose bush expansion.
• The findings contribute to optimizing rose crop management for improved uniformity and visual quality.