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  • Journal of the American Society for Horticultural Science x
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Balancing vegetative growth with fruiting is a primary concern in strawberry (Fragaria ×ananassa Duch.) production. Where nursery plant selection and preconditioning are inadequate for runner control, additional approaches are needed. The gibberellin biosynthesis inhibitor prohexadione-Ca (commercial formulation Apogee) was tested over two seasons for suppressing fall runners of `Chandler' plug plants in a cold-climate annual hill production system. Prohexadione-Ca was applied as a foliar spray at active ingredient concentrations ranging from 60 to 480 mg·L-1, either as a single application 1 week after planting, or repeated at 3-week intervals. The lowest rate resulted in inadequate runner control, with some runners producing malformed daughter plants. Higher rates resulted in 57% to 93% reductions in fall runner numbers, with a concomitant increase in fall branch crown formation. There were no effects of the prohexadione-Ca treatments on plant morphology the following spring, and no adverse effects on fruit characteristics or yield. Chemical names used: prohexadione-calcium, calcium 3-oxido-4-propionyl-5-oxo-3-cyclohexene-carboxylate.

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; Apogee Instruments, Logan, UT), and air temperature with a thermocouple (TMC1-HD; Onset Computer Corp., Bourne, MA), in a naturally aspirated solar shield (RS3; Onset) every 15 s in a growth chamber; and averages were recorded by a data logger (HOBO U12

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bench and grown inside the shading structures or in full sun. Quantum sensors (SQ-110; Apogee Instruments, Logan, UT) connected to a data logger (EM50; Decagon Devices, Pullman, WA) were placed on top of each bench at plant height and monitored the PPF

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thermocouples (OS36-01-T-80F; Apogee Instruments, Logan, UT) were installed on each shelf to measure leaf temperature, and precision thermistors (ST-100, Apogee Instruments) measured air temperature within each treatment. Air and leaf temperature were measured

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224 ± 12 μmol·m −2 ·s −1 with a 16-h photoperiod from 0600 to 2200 hr . Light spectral distribution ( Fig. 1 ) and PPFD were measured at 15 cm underneath the light source at nine spots for each treatment using a PS-100 spectroradiometer (Apogee

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than 185 μmol·m −2 ·s −1 , and switched off when ambient PPF was greater than 370 μmol·m −2 ·s −1 . Line quantum sensors (Apogee Instruments, Logan, UT) were positioned at plant height throughout the greenhouse. The sensors measured PPF every 10 s

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vapor pressure deficit (VPD). Photosynthetic photon flux density (PPFD) inside the greenhouse was measured with a quantum sensor (QSO-sun; Apogee Instruments, Logan, UT) connected to a data logger (CR1000; Campbell Scientific, Logan, UT). The cumulative

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calculated and logged. Amplified quantum sensors (SQ-212; Apogee Instruments, Logan, UT) measured PPF every 30 s under each lighting treatment, and the average of each sensor was logged every 15 min by a data logger (Watchdog 2800 Weather Station) and the

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). Temperature sensors housed within a radiation shield and light sensors (SQ100; Apogee Instruments, Logan, UT) were placed at 1 m above ground level close to the tree canopy. The average daily temperature during the duration of the experiment was 18.1 ± 1.3 °C

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3 , auxins, ethylene) ( El-Otmani et al., 2000 ). Limited research has shown that the GA biosynthesis inhibitors prohexadione calcium (Apogee®; BASF, Research Triangle Park, NC) ( Le Roux and Barry, 2010 ; Stover et al., 2004 ) and paclobutrazol

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