Timing of seed collection
The value of a seedlot depends on its authenticity or
"trueness-to-type", germination capacity. general health and ability to
withstand stresses in the field and during storage. To a large extent, selection
of mother trees, of fruits in the tree and the technique and timing of seed
collection determines the quality of harvested seeds. To assure e good quality
seedlot, seed collection Ups should be observed.
SELECTION OF MOTHER TREES
Picture 1
Survey the area for potential mother trees. A good mother tree
should be vigorous, healthy, with abundant and healthy fruits and of good growth
and form representing the purpose for which it is grown (i.e., for timber,
fodder or fruit). Collect only from mature and healthy trees. Avoid very young
trees or plants.
Also, avoid choosing an area where only few trees of the same
species grow, especially if they are naturally cross pollinating. A large
population gives a better chance of selecting good mother trees. Avoid
collecting in stands with numerous poorly-formed, off-colored, abnormal o_r
disease-infected trees. Collect fruits/seeds from trees standing in the center
of the field. Make sure that seeds come from many trees of the same kind and
quality to ensure that the seedlot contains all the representative
characteristics of the variety.
METHODS OF FRUIT/SEED COLLECTION
1. From the ground
Collecting fruits/seeds from the ground is common especially for
large-fruited species or species with seeds that are naturally dispersed.
Although convenient, this practice increases the risk of collecting immature,
empty, decayed/deteriorated and sprouted/germinated seeds. Identifying the
source of seeds (mother trees) would also be difficult, especially when crowns
of trees are interlocking.
Some points to consider in collecting fruits/seeds from the
ground:
· Gather sound fruits and seeds right after they have
fallen. Avoid collecting first fruits that fall during the season as they are
often of poor quality.
· Shedding of mature fruits/seeds may be induced by shaking
the trunks of small trees. Long poles, aided by hooks and ropes, could be used
for taller trees. Lay a mat on the ground to avoid seeds from touching the
ground and to facilitate collection.
Examples of seeds that can be collected from the ground:
· heavy, fleshy fruits
kaatoan bangkal (Anthocephalus chinensis), kamagong (Diospyros
phi/ippensis), santol (Sandoricum koetjape), pangi (Pangium edule)
· medium-sized fruits with hard
kernel
lumbang (Aleurites moluccana), bagilumbang (Aleurites
trisperma), yemane (Gmelina arborea), teak (Tectona grandis), talisay
(Terminalia catappa), kalumpit (Terminalia microcarpa), bitaog (Calophyllum
inophyllum), pill (Canarium ovatum)
· large pods
fire tree (Delonix regia), rain tree (Albizia saman), antsoan
(Cassia javanica), sampalok (Tamarindus indica), ipil (Intsia bijuga), tindalo
(Afzelia rhomboidea), dapdap (Erythrina spp.)
· large capsules
mahogany (Swietenia macrophylla), kalumpang (Sterculia foetida)
· large winged fruits
narra (Pterocarpus indicus), dipterocarps
Picture 2
2. From standing
Picture 3
Direct access from the ground. Pick fruits/seeds from the lower
branches by hand. Bend, cut, break or saw branches. Examples are: calliandra
(Calliandra calothyrsus), madre de cacao (Gliricidia septum), rensoni (Desmodium
rensonii), sesbania (Sesbania rostrata) and katurai (Sesbania grandiflora).
Climbing trees. Pick fruits/seeds from higher branches by
climbing up the trees. This technique assures seed collection from
well-identified mother trees. It is also applicable for small-seeded species,
winged seeds, fruits/pods that split open when mature, or fruits/seeds that are
prone to insect, rodent and mold attack on the ground. Examples are: (1) small
berries or drupes (e.g., Eucalyptus species, bottlebrush); (2) leguminous
species which open their pods on the tree (e.g., ipilipil Leucaena spp.,
Moluccan sau Paraserianthes falcataria, kamachile Pithecellobium dulce, tanglin
Adenanthera intermedia); and, (3) small, winged, wind-disseminated seeds (e.g.,
Benguet pine Pinus kesiya, Mindoro pine Pinus merkusii, Japanese alder Alnus
japonica, agoho Casuarina equisetifolia, dita Alstonia scholaris, African tulip
Spathodea campanulata, kalantas Toona calantas, banaba Lagerstroemia speciosa).
Special skills and support equipment (like ladders, climbing
iron with spikes, safety belts) are needed to access fruits from higher parts of
the tree.
3. From crowns of felled trees
Collection of seeds from felled trees is easier and usually a
lot quicker. However, this should be avoided as much as possible since this
could lead to significant reduction in tree population and expose the soil to
erosion.
TIMING OF SEED COLLECTION
1. Collect fruits/seeds at about mid-moming or midafternoon when
it is sunny and not windy. This avoids pod shattering or obtaining pods or seeds
that are moist with dew.
2. Harvest fruits/seeds only from trees where most of the fruits
are mature (i.e., avoid overmature and immature ones). Do not collect seeds from
fruits that flowered early or late.
3. To know when a fruit or seed is mature requires familiarity
with the species. Some common indices of maturity are changes in size, texture
and color (usually from green to various shades of yellow, red, purple, brown or
black). Certain fruits dry up while others become soft and sometimes aromatic
when ripe. Collect seeds from shattering fruits, cones or pods (e.g., pine,
eucalyptus, ipil-ipil Leucaena spp., agoho, Moluccan sau, banaba, Acacia
mangium, akle Serialbizia acle and Sesbania) before they dry up and shed or when
still greenish or yellowish in color. Maturity of those with closed cones or
fruits, e.g., Gmelina, can be assessed better by cutting through and examining
the fruit. Collection of green or yellow fruits would also minimize fermentation
during temporary storage of unextracted seeds.
RECORD-KEEPING
Mark mother trees for future collection. Record the site,
location of trees within site and date of collection. This will serve as
reference in evaluating performance of seedlots in relation to origin and seed
source (provenance) as well as predicting seed longevity.
TABLE 1. SAMPLE SEED COLLECTION SCHEDULE OF SOME COMMONLY
USED AGF SPECIES.
