The Interaction of Temperature on Flowering of Alstroemeria ‘Regina’1

Abstract

When Alstroemeria ‘Regina’ plants were programmed to flower after 6 or 8 weeks at 5°C treatments, flowering was hastened by forcing plants at 18° vs. 13° greenhouse night air temperature. However, the 18° forcing temperature reduced flower production, flowers per shoot and shoot grade when compared to 13° forcing temperatures. Due to the decrease in flower production observed at 18° forcing temperature, a 13° temperature is recommended. When plants were grown for 16 weeks at 13°, an inductive temperature, or for 16 weeks at 21°, a non-inductive temperature, prior to the 5° inductive treatments, the 13° pretreatment without a 5° treatment was as effective as 8 weeks at 5° following the initial 21° pretreatment when forced at 18°. Thus, the cold requirement can be fulfilled either at 5° for a short period of time (6 to 8 weeks) or at 13° over an extended time span (16 weeks). Total shoot production during the flowering span decreased as the duration of the 5° treatment increased.

Role of Light Quality, Photoperiod, and High-intensity Supplemental Lighting on Flowering of Alstroemeria ‘Regina’1

“…Even though we have been able to induce flowering in March by the use of HID lighting, we are unable to promote rapid flowering in early winter, or shortly after the completion of the cold treatment in December (5,6 ).…”

Relationship between Rhizome Temperatures and Shoot Temperatures for Floral Initiation and Cut Flower Production of Alstroemeria ‘Regina’

“…Although researchers have investigated the effect of alternating temperatures (10,15), constant low air temperatures (4,5,7,13,14,15), or high air temperatures (4,5,8,13,14) on growth and flowering of alstroemeria, no one yet has shown a definite relationship between controlled soil temperature and floral induction (Table 1) or soil/air temperature X photoperiod with flower induction and generative shoot production of Alstroemeria 'Regina' (Table 2). Lin (11) reported that circulating 10°C tap water in pipes 25 cm below the soil surface increased spring-summer production, and a 16-hr high-pressure sodium lighting regime reduced flowering.…”

“…The exact control mechanisms for Alstroemeria 'Regina' flower induction, initiation, and development are not clearly understood (4,5,6,7,8). Several workers have shown the influence of air temperature on generative alstroemeria shoot induction and subsequent shoot and flower development (3,5,6,7,9,10,14).…”

“…The exact control mechanisms for Alstroemeria 'Regina' flower induction, initiation, and development are not clearly understood (4,5,6,7,8). Several workers have shown the influence of air temperature on generative alstroemeria shoot induction and subsequent shoot and flower development (3,5,6,7,9,10,14). Work in Norway by Mourn and Stromme (13) showed that air temperatures above 21°C reduced the flowering response of Alstroemeria 'Regina' and 'Orchid'.…”

The Effect of Soil Cooling and High Intensity Supplementary Lighting on Flowering of Alstroemeria ‘Regina’

“…In winter, only plants treated with the combination of soil cooling and HPS lighting produced flowers.Recent research on Alstroemeria (Lily-ofthe-Incas) flowering has been devoted to its earliness (3, 4). Early flowering increases the production span and thereby productivity, because all Alstroemeria plants cease flow ering at about the same time, regardless of previous photoperiod treatments (5).Temperature and light have been studied previously with regard to Alstroemeria flow ering (1,3,4,9). It has been suggested that Alstroemeria flowering involves a phasic mechanism in which thermophase precedes photophase (3).…”