Some time ago, a fellow kiwi was on holiday in Vietnam, near Cat Tien National Park, eating some bananas. Unusually though, inside one of the bananas were 10 seeds (the rest were seedless). She kindly posted the seeds to me. This post is about what happened when I grew them.
It’s not well known, but seedless edible bananas can set seeds under certain circumstances. As a very brief primer, edible bananas are parthenocarpic, which means that fruits can be set without any pollination. This is also how seedless mandarins produce fruit.
Furthermore, edible banana varieties are often partially or almost completely sterile (which can come from male or female sterility, or both), which means that even if the flowers were successfully pollinated, no embryo would form, so no seeds. Seedless mandarins by contrast usually are female fertile, and thus can produce seeds if pollinated by fertile pollen. Hence the advice to plant seedless mandarins alone, far away from lemons and grapefruits.
The rates of viable seed set in edible bananas vary depending on the variety. Pisang Awak type [ABB] as well as Blue Java {ABB] are on the slightly fertile side. The late Roger Bodie of Gisborne bred his Wainui banana from a Pisang Awak crossed with a Blue Java.
Cavendish [AAA] is on the almost completely infertile side (horror stories of a ton of carefully hand-pollinated bananas being mushed through a sieve, one by one, to get a handful of mostly infertile seeds).
Edible banana varieties (with few exceptions) are classified as Musa × paradisiaca, which is legal to import as seed into New Zealand under the ‘Basic’ category. These seeds were legally imported via mail.
We planted the 10 seeds on the 24th July, 2023, using Tui seed raising mix (has a bit of fungicide in it, which is useful for seeds that have to sit for a very long time), and left them in the kitchen, with a bag to cover the top of the pot to hold in humidity. I fairly regularly misted the surface of the soil and the inside of the bag to keep them moist.
On about the 15th of May 2024, we noticed one seed had sprouted! A little green spike straight out of the soil. 10 months until the first one sprouted – one must be patient to sprout banana seeds. I shared this with banana expert Gabe Sachter-Smith and he mentioned that it’s very common for banana sprouts from these varieties to stall, and then die, so to not get our hopes up too high.
Gabe also reckoned that it was mostly likely the seeds were from a Pisang Awak type (a common variety in this part of Asia, and regularly produces seeds if pollinated), pollinated by a Musa balbisiana, which are also commonly planted in villages and farms in Vietnam. The seeds and dried fruits of M. balbisiana are used medicinally, the leaves are used for wrapping food and the pseudostems are used for animal feed.
In early August, the sprout looked like this. It’s not just the lighting, it was actually yellowish. I used the ‘twang’ test to determine that it had essentially no roots at this time (lightly twang the plant, and if it vibrates, it’s rooted, if it just shifts in the direction of the twang, it has few/no roots). Another seed had also sprouted as well (barely visible in the photo, since deceased).
By November, the seedling seems to have cleared the danger zone (where it is still relying on stored energy from the seed rather than its own roots), and was now firmly rooted and growing faster. The other seed that had sprouted had since died, however another had sprouted (still alive as of posting, although minuscule in size and not yet passed the danger zone)
By now, I also noticed that the leaves were quite thick, compared to my diploid banana plants (e.g. Musa yunnanensis, which I will write a post about soon), and more in line with the thickness of some Dwarf Cavendish plants. Without getting too deep into the details, this could be a sign of the plant having higher ploidy levels (i.e. it could be triploid or tetraploid). Pisang Awak itself is triploid, and it can often produce triploid or tetraploid offspring, as well as diploid.
By late December 2024, the seedling looked like this:
It had started to gain a lot of red pigmentation around the petioles and pseudostem, presumably from the increased sunlight. There is a waxy coat on the undersides of the leaf, and it doesn’t currently look like the petiole canal will close up. I’m no banana expert, but it looks to me like it has more acuminata genes than balbisiana. It looks a bit like a Jamaican Red. We shall see.
So long as the plant inherits genes for parthenocarpy (ability to produce fruits without pollination), it should produce edible fruit (if it is tetraploid, it is guaranteed to have these genes from the mother). I won’t be upset if the plant is fully female fertile (=sets seeds if pollinated), as quite often most banana growers in New Zealand chop off the male part of the flower (the bell) anyway, so it’s unlikely there’ll be much banana pollen being transported around by bees, and even if there are seeds, it’s useful for further breeding.
With luck it could be a new edible banana variety for New Zealand. There is still a lot of work to do to trial this banana outside and see if it can grow and fruit successfully, but this is a great first step.
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