## 2 Materials and Methods
### Environmental Control and Growing Conditions  
Plants were grown in a growth chamber (8.6 m\({}^{2}\)) inside a Phytotron research facility at North Carolina State University (Raleigh, CA, USA). Temperature, relative humidity (SHT75, Sensirion, Laubisruetistrasse 50, 8712 Staefa ZH, CH) and carbon dioxide (Vaisala CARBOCAP, Vaisala, FI-00421 Helsinki, Finland) sensors were deployed in an aspirated box inside the chamber. In addition, nine fine-wire thermocouples (type T, gauge 24, Omega Inc., Stamford, CA, USA) were deployed (one per treatment and replication) to measure canopy temperature. All environmental data was recorded every three minutes (aspirated box) and every minute (thermocouples) using a datalogger (CR1000, Campbell Scientific, Logan, UT, USA). Environmental parameters are reported for two experimental periods, weeks 01 to 12 and 12 to 21, each with three replications as shown in Table 1. The temperature used in this experiment (26 \({}^{\circ}\)C, Table 1) was greater than the recommended growing temperature for strawberry fruit production of 18 to 21 \({}^{\circ}\)C [24; 25; 26] since it has been reported that warmer temperatures increase stolon and daughter plant growth [24; 27]. \begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline
**Treatment** & **PPFD \({}^{\star}\)** & **Photoperiod** & **Tem.** & **VPD** & **RH** & **CO\({}_{2}\)** & **Irrigation** & & **Drainage** \\ \hline  & \(\mathbf{\mathrm{\upmu mol}}^{-2}\) s\({}^{-1}\) & **h** & \({}^{\circ}\)C & **kPa** & **\%** & **Mmol mol\({}^{-1}\)** & **pH** & **EC** & **pH** & **EC** & **\%** \\ \hline  & & & & 01–12 weeks & & & & & \\
250-PPF & \(241\pm 13\) & & & 25.7 \(\pm\) 0.2 & & & & & & \\
350-PPF & \(337\pm 13\) & 12 & 25.8 \(\pm\) 0.2 & 0.98 \(\pm\) 0.24 & 70.6 \(\pm\) 8.0 & 438 \(\pm\) 37 & 6.8 \(\pm\) 0.7 & 12.2 \(\pm\) 0.2 & 5.0 \(\pm\) 0.9 & 1.0 \(\pm\) 0.3 & 29 \(\pm\) 14 \\
450-PPF & \(443\pm 17\) & & & 25.7 \(\pm\) 0.2 & & & & & \\ \hline  & & & & 12–21 weeks & & & & & \\
250-PPF & \(241\pm 8.0\) & & & 25.8 \(\pm\) 0.1 & & & & & \\
350-PPF & \(336\pm 12\) & 12 & 25.7 \(\pm\) 0.2 & 0.92 \(\pm\) 0.05 & 76.9 \(\pm\) 2.3 & 450 \(\pm\) 41 & 5.5 \(\pm\) 0.3 & 1.1 \(\pm\) 0.2 & 5.7 \(\pm\) 0.4 & 1.3 \(\pm\) 0.3 & 15 \(\pm\) 12 \\
450-PPF & \(440\pm 15\) & & & 25.7 \(\pm\) 0.2 & & & & & \\ \hline \hline \end{tabular}  
* Photosynthetic photon flux density measured at the plant canopy every 3 weeks.  
\end{table} 
Table 1: Light intensity treatments and environmental parameters measured inside the growth chamber. Average and standard deviations of the three repetitions for two growing cycles (week 01 to 12 and 12 to 21 weeks). Plants were subjected to three different light intensity treatments measured with a quantum sensor (LI 1500 Sensor Logger and LI 190R Quantum Sensor, LI-COR, Lincoln, NE, USA) as follows: (1) 250-PPF (241 \(\pm\) 13), (2) 350-PPF (337 \(\pm\) 13), and (3) 450-PPF (443 \(\pm\) 17) photosynthetic photon flux density (\(\mu\)mol m\({}^{-2}\) s\({}^{-1}\)) provided by cool white fluorescent lamps (4100 K) (Table 2, Figure 1). Plants were grown under a short-day photoperiod of 12 h to reduce flowering since recent reports showed that \"Albion\" initiates flowers faster under long-day conditions [4]. Horticultural shade cloth (Harmony 4647 FR, Harmony 3315 FR, and Luxous 1347; Ludvig Svensson, Inc., Charlotte, NC, USA) was used to adjust the light intensity under each treatment. In addition, the shade cloth was adjusted every three weeks to ensure that photon flux density at the canopy level was within 10% of the initial intensity. The nutrient recipe used included (mg L\({}^{-1}\)) 80 NO\({}_{3}\)-N, 20 NH\({}_{4}\)-N, 21.4 P, 145.2 K, 60 Ca, 12.2 Mg, and 39 S, as well as micronutrients. The nutrient solution was delivered using a drip-irrigation system controlled by three soil moisture sensors (ECH\({}_{2}\)O EC-5, METER Environment, Pullman, WA, USA). Before the start of the experiment, sensors were calibrated to trigger irrigation when the substrate reached 35% volumetric water content.