Image © 2005 Frans Holthuysen All Rights Reserved
Dr. Roland Fischer
Many thanks to Roland for his help in making me think more rigorously re seed germination. We, together with others on the Passiflora e-group, are doing a series of experiments to find out how best to harvest, store & germinate seed from these plants. There has been surprisingly little experimental work done on this subject. Why is this? Principally because there has been little economic pressure to do so as by far the most widely grown are the hard shelled P. edulis varieties. These all germinate very readily and keep relatively well.
For thousands of years Man has known how to clone plants by making cuttings. P. edulis however tends to deteriorate after 3-4 years & of course if moving to a new area, fruit containing seed or dried seed is easier to carry than a cutting. Accordingly man has been experimenting with growing P. edulis from seed for thousands of years to produce quickly maturing & free flowering short lived plants with tasty fruit which germinate easily. Even today large scale commercial growers will usually grow each generation afresh from seed to maintain vigour, though of course research is being done to produce even better varieties. Nevertheless seed germination is not a commercial problem. The more common decorative species such as P. caerulea, and of course all hybrids, are however propagated on a large scale by cuttings to keep the specific characteristics of any selection that looks & performs better than others. Again P. caerulea is also easily propagated by seed.