|Seeds and Plant Propagation. Agroforestry Technology Information Kit (IIRR, 1992, 105 p.)|
A. For dry fruits (pods and cones)
Sun-dry over concrete, canvas sheets or cloth sacks until pods split open. Placing the pods on a wire mesh with an accompanying container at the bottom is also a good technique. The container will catch the seeds when the pods split open.
Trample with feet, toss around or beat pods inside a sack to speed up seed separation. Open manually or mechanically pods/cones which do not easily split open.
Clean seeds by blowing or winnowing.
To get cleaner and better quality seeds, immerse seeds in a container of water for one to several hours. Discard those that float. Drain and redry the remaining seeds well. Avoid soaking seeds for too long as this may cause fermentation. Soaking should also be avoided for seeds which rapidly expand to avoid damage. When seeds are to be planted immediately, redrying may be omitted.
B. For fleshy fruits
If possible, extract seeds only upon arrival at the collection center. Do not delay extraction for too long and never store fruits piled-up and undisturbed, as heating and fermentation may kill the seeds or reduce their quality.
Seeds in fleshy fruits may be extracted manually or made to undergo a depulping process. This process entails the following steps:
1. Immerse fruits in water for 1-2 days until the fleshy tissue becomes soft.
2. Scrape, crush or nub lightly with hands to separate seeds thoroughly from pulpy flesh, but avoid injuring the seeds.
3. Discard all floating seeds and pulp (most seed species are sinkers.
4. Drain seeds, rewash and air-dry for 1-2 days before sun-drying.
5. Winnow to dean.
Examples of species with fleshy fruits that need depulping: Aleurites spp., Canarium ovatum, Syzygium cumin), Gmelina arborea, Azadirachta indica, Ocotea usembarensis and Cinnamomum camphora.
For some species which have seeds covered only by thin layer of flesh (e.g., Vitex parviflora), the fruit itself may be kept intact, dried and directly sown. However, germination may be further improved by removal of the pulp.
DRYING OF SEEDS
Sun-dry the extracted, cleaned seeds for 1-3 days (depending on the weather and on how wet the seeds are) if seeds will be stored for future use. Airdry washed or wet seeds for 1-2 days before sundrying.
1. Lay a mat, canvas, light-colored plastic sheet, winnowing basket or screen on the ground where the sun shines all day.
2. Spread the seeds thinly and evenly.
3. Stir and turn the seeds 4-5 times a day for uniform drying. If possible, keep seeds (especially moist ones) shaded during intense heat (noon to 2:00 p.m.).
4. Before it rains or gets dark, take the seeds indoors.
The same drying procedure may be used for seeds of most fruit trees. Exceptions are seeds of lanzones (Lansium domesticum), rambutan (Nephelium eappaceum), durian (Durio zibethinus), mangosteen (Garcinia mangostana), man go (Mangifera indica), jackfruit (Artocarpus heterophyllus), avocado (Persea americana), rubber (Manihot glaziovii), cacao (Theobroma cacao) and Dipterocarpus spp. These should not be sun-dried but may be air-dried for a day or two before storing or they must be planted immediately after extraction.