Growth and flowering in Cyrtanthus elatus : a thesis presented in partial fulfilment of the requirements for the degree of Master of Horticultural Science at Massey University
Cyrtanthus elatus (Hilliard and Burtt, 1986), commonly called Vallota, is a bulbous plant native to the Southeastern Cape province of South Africa, bearing an inflorescence with several large, bell-shaped, red flowers. The bulb and flower morphology, plus development of the inflorescence is described and was similar to Eucharis and Hippeastrum. Sympodial growth of leaves and inflorescences occurred from meristematic cells at the centre of the basal plate. A terminal inflorescence was initiated after 5-7 leaves. Large bulbs (7 cm diameter) had 5 leaves per growth unit and up to 5 inflorescence buds. Temperature and light intensity influenced growth and development of C. elatus. Inflorescences were initiated over a range of temperatures (13-29°C). Vernalization was not required. Floral initiation was optimal from 21-29°C and development to anthesis was optimal at 25°C. Quality of florets was best at 21°C which resulted in larger, brighter, orangey-red flowers. Rates of floral initiation were not affected by shading (50%), however, shading resulted in a high level of inflorescence bud abortion, particularly at warm temperatures (mean 23°C). Inflorescences did not emerge under 50% shade. Scapes were longest at 21-25°C, light intensity 722µMm-2s-1 . Inflorescence quality was maintained in a simulated home environment and past the macrobud stage, was independent of inflorescence development. Fluctuating warm temperature (17-26°C) and high light intensity (784µMm-2s-1 ) resulted in maximum root, shoot and offset growth. Good quality plants can be produced year-round under warm conditions (17-26°C), with two inflorescences per year from mature bulbs. Scheduling is complicated by the lack of a vernalization requirement. Shading is not recommended during production, Shipment in the dark at the macrobud stage is possible without deterioration. C. elatus is suitable as a patio and as an indoor pot plant.
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