Narcissus and Daffodil

Agronomic factors and galanthamine production 279
et al., 1990), chipping (Flint and Alderson, 1986), and micropropagation (Squires
and Langton, 1990). Mechanised chipping (Hanks, 1989) is a large-scale propagation
method for abundant low-priced stocks of narcissus. In terms of achieving
high numbers of propagules, the micropropagation procedure can reach 2.5 million
in five years, much greater than the numbers produced by twin-scaling or chipping.
However, due to the high cost of the facilities and the intensive labour
required, micropropagation remains complementary to chipping and twin-scaling
in the ornamentals industry. Currently, micropropagation is only used to a very
limited extent on narcissus, to multiply small stocks of elite, virus-free lines and
cultivars, and for germplasm propagation in breeding programmes. A combination
of available propagation methods may be the wisest strategy to increase narcissus
bulb stocks for galanthamine production. However, the magnitude of the losses,
economic and otherwise, that AD causes to patients, families and society, may
justify the high cost of micropropagating narcissus bulbs for medicinal purposes.
Therefore, micropropagation may be more affordable in the pharmaceutical
industry than in the ornamentals industry. If so, micropropagation could rapidly
increase propagule stocks of high-yielding cultivars such as ‘Inglescombe’, improving
biomass quality for better extractable yields.
Growth and biomass yield
As long as the supply of galanthamine relies on natural sources, there will be
an increasing need to optimise biomass production and extraction to achieve
maximum yields. A research programme on galanthamine supply from natural
sources has both short- and long-term strategies. The short-term strategy includes
a procedure with three fundamental steps, which will indicate the feasibility of
pilot-scale production system. The first step consists of the identification of taxa
found in abundance that could become a reliable source for establishing a production
system. The second step is the optimisation of growing conditions and
agronomic practices to maximise field production of the abundant source. The
third step constitutes the development of a large-scale extraction and separation
method to improve the yields of galanthamine isolated.
The long-term strategy consists of selecting high-yielding Narcissus taxa and
other Amaryllidaceae, maintaining germplasm collections, mass propagating elite
plants, and field studies to enhance yields in an already established production
system. At the National Center for Natural Products Research, four widely available
Narcissus cultivars, ‘Geranium’, ‘Mount Hood’, ‘Cheerfulness’ and ‘Ice Follies’,
have been identified and evaluated for agronomic factors affecting their
yield. The results indicated that planting depth, bulb size, planting density and the
removal of flower buds did not influence drug content. However, these factors did
influence bulb growth, and therefore drug yield per unit of cultivation area (Table
10.2) (Moraes-Cerdeira et al., 1997b). ‘Cheerfulness’ and ‘Geranium’ exhibited
good growth but low galanthamine content, thus showing little promise for drug
production.
Planting density is a complex issue. Under dense plantings, the decreased
growth rate reduces the yield per plant, but the biomass yield per unit area of land
increases (Rees et al., 1973). Galanthamine content is unaffected by high-density
plantings. Therefore, depending on the growth increase, planting density may