Main findings: Shaking of Jatropha seeds in locally available platic bottles is not efficient in sorting seeds according to size.

Large seeds should be selected for propagation because large seeds are generally associated with higher yield, higher germination rate and higher relative oil content. Small differences in seed size are difficult to detect by eye so it was tested if the selection can be made by shaking seeds in a container and then skim the top seeds. Ten batches of 300 gr of seeds were shaken in a 1.5 liter disposable drinking bottle for 45 seconds. The container was prepared so seeds could easily be extracted from the top and bottom.

The seeds from the top had an average weight of 13,5gr and the bottom seeds averaged 12,9 gr. A two-tailed t-test gave p=14% so the differences are not significant.

It was difficult to move the container only vertically. The result was that the seeds in the container tended to describe a circular movement where the seeds would rise on one side of the container and sink on the other side. A device or technique that ensures vertical shaking only may work better.

Commercial machinery exist but the cost is only justifiable if sufficient amounts of seeds is processed. It may be economically viable to have seed processing equipment at BBC, particularly at the present time when the demand for and the price of quality seeds is high.