Smart Scheduling of Wave Green Circle Growers February 21, 2011 Sonali Padhye Technical Services, PanAmerican Seed

Scheduling Wave Petunias

Rate of Plant Development

Smart Scheduling of Wave Petunias Objective: To generate a flowering model for scheduling Wave petunias to flower on a specific date Experiment conducted at Michigan State University Plants were under LD throughout the study

Sixteen Wave Cultivars Used

Experimental Protocol Seeds sown into 288-cell plug trays by C. Raker & Sons in late January

Experimental Protocol Seedlings grown in growth chambers: At 16-hour photoperiod Fluorescent + incandescent lamps at 130 to 150 µmol·m -2 ·s -1 Constant temperature of 20 °C (68 °F) No PGRs were applied to the plugs

Plugs in Growth Chamber February 1

Experimental Protocol Seedlings with 6 to 9 leaves were transplanted into 4” pots and grown pot- to-pot under a 16-hour photoperiod (HPS lighting).

Plugs at Transplant ‘Easy Wave Neon Rose’ ‘Shock Wave Purple’ ‘Tidal Wave Silver’

Experimental Protocol Experimental treatments: Daily light integral (DLI): Low (7 mol·m -2 ·d -1 ) Moderate (14 mol·m -2 ·d -1 ) Temperatures: 12, 15, 18, 21, or 24 °C (54, 59, 64, 70, or 75 °F)

Experimental Setup

Petunia ‘Easy Wave Neon Rose’ 16-hour photoperiod at constant: 12 °C 15 °C 18 °C 21 °C 24 °C 14 mol·m -2 ·d -1 7 mol·m -2 ·d Average days to flower from transplant of 288-cell plug Photos taken 37 days after transplant

Flowering Responses of Sixteen Wave Cultivars

Wave Smart Scheduling Model

Limitations of the Flowering Models Two DLIs Based on only one (albeit large) experiment Starting material: 288-cell plugs grown under LD The maturity of the plug, and the conditions under which plugs are grown, can influence flowering time.

Limitations of the Flowering Models The models are only valid within 12 to 24 °C and a DLI of ≈5 to 15 mol·m -2 ·d -1 Predictions may not be valid outside of this range, especially at higher temperatures and higher DLIs. Models predict the time to first open flower and not full flowering (shipping stage).

What’s the Next Step?

Validating the Models 1.Starting material: 1.Average leaf # 2.Plug tray size 3.Plug culture 2.At least 10 plants per variety – more is better 3.Transplant and flowering date for each plant 4.Leaf number at flowering? 5.ADT and DLI data 6.PGRs

Model based on Days vs Leaf # Leaf #: Easter lily flowering model – More work to count leaves – More accurate – little effect of starting material What would make most sense for petunia? Questions or Comments?