Photoperiodic Response and Vase Life of Ornamental Sunflower Cultivars

Abstract

<jats:p>Photoperiodic response and vase life of 28 cultivars of ornamental sunflower (<jats:italic>Helianthus annuus</jats:italic>) were evaluated. Plants were grown in a glasshouse under 16-hour long-day (LD) or 11.5-hour shortday (SD) conditions. Most cultivars (82%) reached visible flower bud stage earlier under SD than LD. All cultivars flowered under both SD and LD conditions, but in 26 cultivars (92.9%) flowering was significantly delayed under LD, demonstrating them to be quantitative SD plants. The delay was variable among the cultivars. A 14-day or greater hastening of flowering was found under SD in 18 cultivars. Photoperiod had no effect on flowering of `Lemon Eclair' and `Moonshadow'; these cultivars are day-neutral (DN) plants. For some cultivars the LD photoperiod increased plant height and the number of nodes and leaves. Vase life varied from 6.8 to 11.2 days depending on the cultivar, but no photoperiodic effect was found.</jats:p>

Transitions in photoperiodic flowering are common and involve few loci in wild sunflowers (Helianthus; Asteraceae)

“…Moreover, Texan populations, known to have established during a relatively recent southward range expansion (Rieseberg et al, 1990; Whitney et al, 2006), exhibit a facultative long‐day response. Similar variation in photoperiod response is also observed among cultivated accessions, and cultivars with additional, more complex responses have been reported as well (Allard and Garner, 1940; Dyer et al, 1959; Goyne and Schneiter, 1987; Leon et al, 2001; Yanez et al, 2005; Blackman et al, 2010). However, with the exception of the Jerusalem artichoke, H. tuberosus , another taxon of agronomic interest in the genus (Hackbarth, 1937; Kays and Nottingham, 2008), the diversity of photoperiod response within and between Helianthus species has not been extensively surveyed.…”

Effects of time and duration of short-day treatments under long-day conditions on flowering of a quantitative short-day sunflower (Helianthus annuus L.) ‘Sunrich Orange’

“…The desirable stem length and cut flower weight are approximately 80 cm and 5 70-100 g, respectively. Although some cultivars are day-neutral and flowering is not affected by photoperiod (Robinson et al, 1967;Schuster, 1985;Vince-Prue, 1975;Yanez et al, 2004;2005), the number of such cultivars is limited. Therefore, establishing a method to promote flowering of quantitative SD sunflower cultivars under LD conditions is highly desirable.…”

“…In order to promote earlier flowering and to improve flower quality of qualitative SD 10 sunflower cultivars, we investigated the effects of time and duration of SD treatment on flower bud development and flower quality of sunflower 'Sunrich Orange' grown under LD conditions. This cultivar was chosen because it is a quantitative SD plant (Yanez et al, 2005).…”

Year-round Greenhouse Production of Cut Sunflowers in the Rocky Mountain West

“…Significant interactions between time of year and cultivar for stem length and days to harvest were likely associated with changing photoperiods and the different responses to photoperiod displayed by the three cultivars. Different responses of sunflower cultivars to photoperiod are well documented (Blacquière et al, 2002;Gimelli et al, 2003;Hayata and Imaizumi, 2000;Schuster, 1985;Wien, 2009b;Yañez et al, 2004Yañez et al, , 2005Yañez et al, , 2012.…”

“…The potential for year-round production of cut sunflowers has been investigated in other states and countries such as Hawaii (Criley, 2007), New York (Wien, 2006(Wien, , 2007(Wien, , 2012a(Wien, , 2012b, Italy (Gimelli et al, 2003), The Netherlands (Blacquière et al, 2002), and Japan (Hayata and Imaizumi, 2000;Yañez et al, 2004Yañez et al, , 2005. Studies concerning yearround production are of interest because, although many cultivars are day neutral, photoperiod may affect flowering of some cultivars (Hayata and Imaizumi, 2000;Wien, 2006Wien, , 2007Wien, , 2012aWien, , 2012bYañez et al, 2004Yañez et al, , 2005. Although studies on year-round sunflower production have been conducted in other regions, they took place under climatic conditions quite different from those found in the Rocky Mountain west; local climate has been shown to be a major factor in cut sunflower production (Ferguson et al, 2012;Fernández-Martinez et al, 2009;Schuster, 1985).…”