ISHS Acta Horticulturae 620: XXVI International Horticultural Congress: Asian Plants with Unique Horticultural Potential: Genetic Resources, Cultural Practices, and Utilization
INFLUENCE OF TEMPERATURE ON GROWTH AND FLOWERING OF FOUR MECONOPSIS GENOTYPES |
| Authors: | S. Still, S. Kitto, J. Swasey, J. Harbage |
| Keywords: | blue poppies, temperature effects, net photosynthesis |
| Abstract:
Meconopsis betonicifolia Franch. and M. grandis Prain are members of the Papaveraceae L. native to the Himalayan mountains. These species and the hybrids derived from them are especially prized as ornamentals for their intense blue flowers and gardenesque habit. Longwood Gardens, a horticultural display garden in eastern Pennsylvania, USA, has identified these plants as ideal for conservatory display. However, empirical observations indicate these species are intolerant of the hot summers that occur in this geographic region. The experiments were designed to identify how temperature would affect plant characteristics critical to display for blue flowered Meconopsis as well as the red flowering M. punicea Maxim. Meconopsis betonicifolia, M. ‘Lingholm’, M. George Sherriff Group variety, and M. punicea plants were forced in the greenhouse at minimum night/day temperatures of 7.2/10 °C, 12.8/15.6 °C, and 18.3/21.1 °C between December and May. All plants grown in the 7.2/10 °C and 12.8/15.6 °C temperatures had larger canopy widths when first starting to flower than those plants in 18.3/21.1 °C environment. Plants grown in the two cooler temperature ranges also had longer flower stems, at 64.27 cm and 54.44 cm, for the coolest and medium environment, respectively, than the warmest environment at 46.27 cm. The stem diameter was greatest on plants in the 7.2/10 °C environment at .691 cm opposed to the warm temperatures at 0.526 cm and 0.438 cm for the medium and warmest environment, respectively. Plant dry weight was also inversely related to temperature. Plants grown at 7.2/10 °C, at 41.8 g, were 33 % heavier than those grown at 12.8/15.6 °C, at 31.4 g, and 100 % heavier than the plants in the 18.3/21.1 °C, at 20.6 g, at harvesting. This study showed display quality plants with tall, strong flower stems and good foliage could be grown when temperatures were monitored and maintained at 7.2/10 °C and 12.8/15.6 °C and proper genotypes were selected. | |
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