1999 Volume 68 Issue 1 Pages 160-167
Effects of temperature treatments and soil-cooling methods were evaluated to improve the cut flower yield and quality of autumn flowering Alstroemeria. 1. 'Regina' and 'Carmen' (syn. 'Cana') plants, kept at a minimum of 10°C in winter, continually produced flowering shoots if they were planted by 21 May and 20 June, respectively, provided the chilled soil temperature at night was maintained at 14°C. These critical dates correspond with the time when it became nearly impossible to keep 'Regina' and 'Carmen', respectively, below 15°C and 17°C, which are the critical and threshold temperatures for flowering. Cut flower yield and quality obtained by this method were poor. 2. Potted 'Regina' plants which were previously exposed to chilling at 2°C for 10 weeks and then transplanted in a chilled soil bed on 10 June produced flowering shoots in autumn. The plants raised at a minimum of 20°C prior to the chilling treatment produced more vegetative shoots after transplanting as compared to the plants raised at a minimum of 10°C. The former produced a greater number of flowering shoots and high-quality cut flowers in early autumn. 3. 'Carmen' plants grown in a chilled soil bed, kept below 17°C for only 6 hr at night produced more vegetative shoots and high-quality cut flowers in autumn as compared to the plants grown in a bed cooled continuously. 4. Keeping the soil at 20°C for 8∿20 weeks prior to cooling to 17°C on 12 June produced an abundance of vegetative shoots in summer and autumn and improved the cut flower yield and quality of autumn-flowering two-year-old 'Carmen' plants.
