Narcissus and Daffodil

278 R.M. Moraes
Galanthamine content
mg /100g dry weight
300
250
200
150
100
50
0
AGRONOMIC FACTORS AFFECTING DRUG YIELD
Genetic and environmental factors strongly influence biomass growth and its
content of secondary compounds. To achieve maximum yields of any active compound
such as galanthamine, optimum agronomic practices should be established.
The agronomic practices include the identification of high-yielding cultivars,
optimum growing conditions (climate, soil type, planting density, fertilisation and
irrigation), pest management (weeds, insects and disease), and appropriate
mechanisation for cultivation, harvesting, drying and grinding.
As mentioned above, a survey of more than 80 Narcissus taxa indicated that
Narcissus ‘Inglescombe’ had the highest galanthamine content (Bastos et al., 1996).
However, the current supply of ‘Inglescombe’ bulbs is small and requires a mass
propagation programme to increase stocks for extensive cultivation.
Propagation
I II III IV V VI VII VIII IX X XI XII
Developmental Stage
Figure 10.1 The effect of developmental stages of Narcissus ‘Inglescombe’ on galanthamine
content during the 1994 growing season (unpublished data):
I, pre-emergence (1 February); II, emergence, pre-bud stage (26 February);
III, post-emergence, early bud stage (10 March); IV, anthesis (23 March);
V, post-anthesis, ‘fruiting’ (25 April); VI, senescing (2 June); VII, senescent
(6 July); VIII, senescent (28 July); IX, senescent (29 August); X, root
re-growth (4 October); XI, shoot re-growth (4 November); XII, underground
growth (10 December).
The natural rate of narcissus bulb multiplication is low: the average rate of
increase is 1.6 per annum, or 1 to 1000 in 16 years (Rees, 1969). Faster methods of
propagation are available, such as twin-scaling (Hanks and Rees, 1979; Fenlon