The Agavaceae comprise about 600 species in 20 genera. Certain species are sometimes classified in the Liliaceae (see Chapter 44) and the remainder in the Amaryllidaceae (see Chapter 76).
The genera Agave, Furcraea, Phormium, Sansevieria and Yucca yield hard fibres. For example Agave sisalana Perrine (sisal), Furcraea gigantea Vent. (Mauritius hemp), Phormium tenax Forst. (New Zealand flax or hemp) and Sansevieria guineensis (L.) Willd. (bowstring hemp). Although it can be difficult to produce seeds from vegetatively propagated plants, the seeds are reported to store well and seeds of Agave and Yucca spp. are maintained in the long-term seed store at the Wakehurst Place Gene Bank.
SEED DORMANCY AND GERMINATION
Germination is reported to be epigeal, at least in Agave spp. Seed dormancy can be problematic with poor germination being reported for freshly harvested seeds. Detailed information on seed germination and dormancy-breaking treatments is limited (Table 19.1), but the algorithm below may be helpful in developing suitable germination test procedures for other species in the Agavaceae.
RBG Kew Wakehurst Place algorithm
The first step in the algorithm is to test the seeds at a constant temperature of 16°C with light applied for 12h/d.
If this is not successful in promoting full germination then the second step is to test the seeds in an alternating-temperature regime of 23°/9°C (12h/12h) with light applied for 12h/d during the period spent at the upper temperature.
TABLE 19.1 Summary of germination test recommendations for species within the Agavaceae
|
Species and Authority |
Substrate |
Temperature |
Duration |
Additional directions |
Source |
|
Cordyline australis (G. Forst.) Hook. f. |
TP |
20°/30°C |
30d |
light, pre-soak fruit balls, 1-2d, then extract seeds and
test |
AOSA |
|
Yucca filamentosa L. |
TP |
20°/30°C |
21d |
light, pre-chill, 3°-5°C, 21-28d |
AOSA |
