As most of us know, all of our cultivated bananas are sterile clones and those little black dots in the middle of the fruit are immature seeds which will never develop. Getting a real seed out of a cultivated banana is a really rare event, as we realise immediately when we think about how many bananas we have eaten and how few seeds we have found.
I have been growing Ducasse (sugar) bananas in my back yard for twenty-odd years, occasionally with other varieties, and I hadn’t come across a mature seed in all those years until six weeks ago when I found one seed in each of two bananas from the same bunch. One seed crunched between my teeth but I managed to save the other – roundish, blackish and about 4mm long.
… although banana plants are clones, very occasionally they can be persuaded to produce seeds through a painstaking process of hand pollination. Only one fruit in three hundred will produce a seed, and of these seeds only one in three will have the correct chromosomal configuration to allow germination.
The only oddity about the development of this particular bunch of Ducasse was that I had a Blue Java flowering at about the same time. Perhaps they cross-pollinated with the help of our native bees and fluked a viable genetic combination. If not, they are probably pure Ducasse and I have even less idea why they formed; random mutation seems to be the likeliest reason.
The chances that the seed would be viable enough to germinate are one in three, according to the source I just quoted, but there’s still no guarantee it will flower or that the fruit would be edible if it does germinate. However, the seed has now been in a little tray of potting mix for a week and we will wait and see.
We could be waiting a while, though: Gardening Know How: Propagating Banana Plants – Growing Banana Trees From Seeds says that it is a slow, unreliable process. This answer on Quora is not wildly optimistic either:
Bananas are one of the more difficult seeds to germinate in terms of time and effort required, especially compared to vegetable and flower seeds most gardeners are familiar with, but they can be germinated at a decent rate if one is diligent.
The first thing to understand is that banana seed take a long time to germinate! We have been germinating banana seeds in our germination trials for over 25 years. The normal germination range in our greenhouse trials varies from 1 to 6 months.
Whether we will get any result from our one seed is an open question but there’s no harm in trying. Watch this space.