New cut flower introductions are necessary to maintain and increase consumer interest. Expanding the availability and knowledge of new cut flowers allows growers to select species and cultivars ideally suited for their climates and consumer base. Many exotic bulb species, such as pineapple lily, are underused by the floral industry. The genus Eucomis contains about 15 species (Bryan and Griffiths, 1995) and many hybridized cultivars now exist that vary in color, scent, vigor, and hardiness (Fig. 1). Pineapple lily grows from a true bulb forming a rosette of lanceolate leaves. From that rosette emerges a spike inflorescence composed of star-shaped florets and a terminal tuft of bracts making it resemble a pineapple, from which its common name is derived. The inflorescence has the potential to last for more than a month in a vase with proper postharvest handling (Carlson and Dole, 2014) and even longer on the plant. New cultivars and species appear to have potential, but growers are hesitant to produce new cut flower crops without information on production techniques.
Plant material and production area are costly; therefore, it is important that optimum planting densities be identified to maximize financial return (Rees, 1974). Planting density can strongly affect the yield of bulb crops (de Vroomen, 1974), weed and disease control, and mechanization (Rees, 1974). Increasing planting density to increase productivity per unit area can decrease the productivity per plant, increase stem length, and increase earliness of flowering depending on the species (Rees, 1974). Higher rates of transpiration and reduction in light penetration also occur at higher densities (Rees, 1974). The morphogenic effects of high planting densities may not be seen in the first year because the bulb has sufficient carbohydrate reserves, but future crops may exhibit lower productivity and stem-quality issues (Rees, 1974) making it important to look at the long-term effects of planting densities on perennials. Effects of planting density have not been investigated for pineapple lily.
Growth and flowering of most geophytes is controlled by internal physiological factors, such as dormancy, maturity, bulb storage condition, and forcing temperatures (De Hertogh and Le Nard, 1993). Storage temperature affects the formation of floral organs and the timing of flowering (Hartsema, 1961). In general, temperature is the major environmental factor that influences the flowering process from flower initiation to development in bulb plants (Roh and Hong, 2007). Both temperature and photoperiod are known to affect the formation of floral organs in oriental lily [Lilium longiflorum (Roh and Wilkins, 1978)]. Closely related to pineapple lily, star-of-bethlehem (Ornithogalum thyrsoides) has a relatively shallow dormancy and may continue to grow and flower under favorable environmental conditions and will not enter dormancy (Halevy, 1990). Effective temperature for breaking of dormancy may also vary within species. Little information is known about suitable temperatures for dormancy breaking or flower initiation of pineapple lily.
It is also important for growers to know optimal production temperatures before growing a new crop. Each plant species has a range of temperatures that are tolerable and conducive to plant growth, but extreme temperatures within that range can stress plants resulting in pest/disease problems, unacceptably long production times, or reduced inflorescence quality (Dole and Wilkins, 2005). Growers may have access to different production environments depending on their individual operations. It is important to understand the differences these production environments will have on the productivity and quality of cut stems.
The objectives of this study were to determine the optimal production environment, planting density, bulb storage duration and temperature, and forcing temperature for ‘Coral’, ‘Cream’, ‘Lavender’, and ‘Sparkling Burgundy’ pineapple lily.
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