Flowering and inflorescence development of Lachenalia aloides 'Pearsonii' as influenced by bulb storage and forcing temperature

The effect of bulb storage and forcing temperatures on growth, flowering, and inflorescence development and blast of Lachenalia aloides Engl. 'Pearsonii' was investigated. Bulb temperature treatments began when about five florets were developed. Bulbs were stored at 10 degrees C, 12.5 degrees C, 15 'C, 20 degrees C, and 25 degrees C for 15, 30, or 45 days and forced in greenhouses at 17/15 degrees C and 21/19 degrees C, day (D)/ night (N) temperature. Flowering was accelerated, and leaf length and floret number were reduced, when bulbs were stored at 10 degrees C, 12.5 degrees C, or 15 degrees C for 45 days compared with storing at 20 degrees C or 25 degrees C. Flowering was further accelerated by forcing at 17/15 degrees C compared with 21/19 degrees C (Experiments 1 and 2). When bulbs were stored at 10 degrees C, 15 degrees C, 20 degrees C, or 25 degrees C for 4 weeks and grown in greenhouses at 17/15 degrees C, 21/19 degrees C, 25/23 degrees C, and 29/27 degrees C, D/N temperature, the incidence of inflorescence blast was increased when bulbs were stored at 10 degrees and 15 degrees C and forced at 25/23 degrees C compared with low temperatures (Experiment 3). Bulbs were stored at 10 degrees C, 15 degrees C, 20 degrees C, or 25 degrees C for 4 weeks and forced in greenhouses maintained at 18/16 degrees C, 22/20 degrees C, or 26/24 'C, D/N temperature, for 12 weeks. During forcing, plants were subjected to a constant 18/16 degrees C or temperatures were changed after 4 and 8 weeks (e.g., 18/16 degrees C-22/20 degrees C-18/16 degrees C) (Experiment 4). Inflorescence blast occurred when the temperature was 26/24 degrees C during the first 4 weeks after potting of bulbs that were stored at 15 degrees C (83%) and 10 degrees C (50%). Plants from bulbs stored at higher temperatures did not show inflorescence blast. To produce quality plants with short leaves, many florets, and short floral stems (scape plus inflorescence), it is recommended to store bulbs at 10-15 degrees C before potting for 30 days and to force at 17/15 degrees C to accelerate flowering. Inflorescence development during bulb storage at 10 degrees C and inflorescence blast that occurred after only 3 days of 30 degrees C was demonstrated using scanning electron microscopy and magnetic resonance imaging techniques. (c) 2004 Elsevier B.V. All rights reserved.