Star of bethlehem (Ornithogalum sp.) was first introduced to floriculture as a cut flower, but over the last 20 years has been gaining popularity as a potted plant. The expansion from a cut flower to the potted plant sector, which is supported by new breeding efforts, can help satisfy the market demand for novelty plants. In the U.S. market, potted geophytes used as winter-blooming house plants are especially in demand (Daly and Henry, 2009). More information on improved production protocols can support the further commercialization of potted star of bethlehem.
Unlike cut flowers, excessive stem growth is not desired for potted plants. A compact product with a plant plus pot:pot ratio of ≈1.6 is the theoretical optimum display (Sachs, 1976). Aside from breeding and controlling environmental factors to regulate stem elongation, PGRs are a common way of manipulating plant growth to achieve the desired shape and size. A major group of PGRs are the anti-gibberellin (GA) growth retardants, which act by inhibiting GA biosynthesis at various points in the GA biosynthesis pathway (Rademacher, 2000). The anti-GA PGRs are widely used in the flower bulb industry as sprays or substrate drenches (Currey et al., 2012; De Hertogh, 1996; Miller, 2014). Flurprimidol and paclobutrazol are two commonly used anti-GA retardants. Flurprimidol applied at 15 and 30 mg·L−1 resulted in significantly higher chlorophyll content and shorter flower stems in star of bethlehem [Ornithogalum saundersiae (Salachna and Zawadzińska, 2013)]. While not acting via inhibition of GA biosynthesis, ethephon is also used as a growth retardant in floriculture. Ethephon releases ethylene on application. It can inhibit stem elongation as drench application in daffodil and hyacinth and a range of bedding plants (Miller, 2014; Miller et al., 2012; Moe, 1980). To the best of our knowledge, no publications exist concerning the use of growth retardants in star of bethlehem production.
Anti-GA PGRs can regulate plant height and improve plant uniformity and can contribute to more accurate scheduling of flowering dates, meeting market requirements for plant height, and reduction of shipping costs. Although there are general guidelines suggesting the best ratio for potted plant (Sachs, 1976), commercially acceptable potted plant height is largely a matter of personal preference and varies by plant species. For a commercial grower, the acceptable height is that specified by the customer, either an individual or, in the case of larger growers, the wholesale buyer of the product. Consumers’ preferences and willingness to pay (WTP) for different horticulture products and product attributes have been studied to assist making consumer preference-based market decision (James et al., 2009; Jowkar et al., 2007; Kelley et al., 2000). The objectives of this research were to evaluate the effect of flurprimidol, paclobutrazol, and ethephon as media drenches on stem elongation of star of bethlehem, and consumer preference for potted star of bethlehem plant height.
Currey, C.J., Lopez, R.G., Krug, B.A., McCall, I. & Whipker, B.E. 2012 Substrate drenches containing flurprimidol suppress height of ‘Nellie White’ easter lilies HortTechnology 22 164 168
Daly, M. & Henry, K. 2009 Evaluation of selected South African geophytes as winter-blooming houseplants for the Northern Hemisphere Acta Hort. 813 37 44
De Hertogh, A. 1996 Holland bulb forcer’s guide. 5th ed. Intl. Flower Bulb Ctr., Hillegom, The Netherlands
James, J.S., Rickard, B.J. & Rossman, W.J. 2009 Product differentiation and market segmentation in applesauce: Using a choice experiment to assess the value of organic, local, and nutritional attributes Agr. Res. Econ. Rev. 38 357 370
Jowkar, M.M., Farshadfar, Z. & Rahmaniyan, A.R. 2007 Predicting cut flower consumers’ taste and preference for consumers’ preference based selection in Shiraz, I.R. Iran Acta Hort. 747 75 80
Kelley, K.M., Behe, B.K., Biernbaum, J.A. & Poff, K.L. 2000 Consumer preference for edible-flower color, container size, and price HortScience 36 801 804
Krug, B.A., Whipker, B.E., McCall, I. & Dole, J.M. 2005 Comparison of flurprimidol to ancymidol, paclobutrazol, and uniconazole for tulip height control HortTechnology 15 370 373
Miller, W.B. 2003 Commercial flower production methodology, p. 946–948. In: Encyclopedia of applied plant sciences. Academic Press, Waltham, MA
Miller, W.B. 2014 Flower Bulb Research Program. Cornell University, Department of Horticulture. 6 July 2014. <http://www.flowerbulbs.cornell.edu/>
Miller, W.B., Mattson, N.S., Xie, X., Xu, D., Currey, C.J., Clemens, K.L., Lopez, R.G., Olrich, M. & Runkle, E.S. 2012 Ethephon substrate drenches inhibit stem extension of floriculture crops HortScience 47 1312 1319
Rademacher, W. 2000 Growth retardants: Effects on gibberellin biosynthesis and other metabolic pathways Annu. Rev. Plant Biol. 51 501 531
Salachna, P. & Zawadzińska, A. 2013 The effects of flurprimidol concentrations and application methods on Ornithogalum saundersiae Bak. grown as a pot plant African J. Agr. Res. 8 6625 6628