Postharvest Handling of Seeds

There is often a delay between collecting and threshing. This delay is necessary to allow fruits to mature and inflorescences to dry. The pressure of maximum collection during a short time period before dehiscence also delays threshing.

This delay period is important for seed yield and quality. We have stressed the use of mesh or paper bags for collection of seeds. Plastic bags or wax coated paper should never be used. The moisture content of the freshly collected seeds is quite high and plastic or other nonporous bags will trap this moisture and cause spoilage of the seeds.

A ventilated greenhouse room is an excellent postharvest drying area for seed samples to be threshed. If the collected material is dried outdoors, pro-visions must be made to cover the seeds at night and in the event of winds, rain, or dew.

One method of reducing the amount of plant material to store and dry before threshing is to coarse screen the collected seed or fruit in the field. This simple process consists of screening the collected material through a screen with large enough openings to allow the seeds or fruits to pass through. Coarse trash and waste are left on top of the screen to be discarded. A second screening is made with a screen too small to allow the desired seed to pass through. The seeds are kept on top and fine waste passes through for discarding. Screens can be constructed from hardware cloth or fine wire mesh mounted on wooden frames.

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