Sam g

Hello from Australia!

I am wanting to start a breeding project but am in need of advice. I plan on crossing a tetraploid cultivar with a diploid wild musa sp. I have very little genetics education, but neither did most of humanity for most of history and look what has been produced. However I am unsure how to calculate how many potential offspring I would need to grow to express most of the genetic variants to maximise the chance of producing a useful plant, I.e. Parthenocarpic.

I am seeking reading material or advice? Either would be appreciated!

Thanks in advance.
Sam

Gabe15

There is no real answer to your question unfortunately, and no way to calculate it. Being parthenocarpic is not the only useful trait, you need to look at the entire plant and everything about it. A plant may be parthenocarpic, but terrible in all other traits. And if you are just breeding for parthenocarpy and nothing else, then there would be no point, as you are starting with a parthenocarpic parent, so from the non-parthenocarpic parent you must be seeking some sort of traits from it too.

Whatever happens is highly dependent on what parents are being used, and how many seedlings you will actually be able to generate.

For something like this, I think you are looking way too far down the road and with too much expectation, see if you can make a cross, grow seed, and generate any seedlings at all before you get caught up in thinking about technical details like this, it's a lot harder than you may think. Try generating 1 seedling before you get worried about what might be useful to consider if you manage to generate 100 or more.

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druss

Gabe is right, its all about traits. So you need to consider what your after and then work out how to get there. Bananas are messy breeders so you rarely end up with the ploidy you planned. There are people doing home crossing, but its not easy, a satisfactory result may take 2 decades. So with that in mind consider the following:
Goal: What trait from your wild plant are you after? Cold hardiness, cycle time, plant size, flavour?
Sterility vs parthenocarpy: These are different, some bananas are both some have residual fertility, occasionally literature lists whether a variety is male or female fertile, worth checking your selected variety isn't a mule.
Compatibility: Aside from the already Inbuilt sterility, some wild sp simply don't cross with the domesticated musa, m.basjoo is one that gives little to no success, m.ornata crosses readily with vigorous hybrids. If I can find the literature on research done by the qld ag dept I will post.
Pollination: Banana pollen doesn't store, so you need to have both plants flowering simultaneously, 6 plants of each is considered minimum, or if you know which your using as male and female plant 1 of the male and a dozen of the female, that will give you good odds of pollination time cross over, best case after hand pollination expect 0-5 seeds a bunch. One of those may be viable, the rest will need embryo rescue.
Tracking: Once you get your first generation crosses you will be able to see what traits you got, but its unlikely you'll get a gen 1 hybrid with everything you desire, so then you need to remove all the no longer needed and plan the next crosses. Good luck.

Sam g

Hi Gabe thanks for your information! I should have clarified my intentions in the initial post. I live in Tasmania, which is a large island off the southern end of Australia, we have zones 9b and 10a here even though we sit 40 degrees latitude south from the equator. Being an island we have a very mild climate moderated by the ocean. Our summer temperatures rarely go above 80 degrees f. Our summer growing season is normally around 5 months. There is commercial avocado farms here too.

So given the above information I have been thinking of breeding the cool tolerant gold finger (FHIA-01) with the short cycling M. Velutina to see what could potentially arise. Hopefully there could be a shorter cycling cool tolerant edible banana.

I understand that many people on here have looked into similar ideas for short season areas and I have been reading everything I can find on here to understand what to try. I came across an article about the 4x/2x strategy that
Frederic Bakry had been practicing; Banana breeding’s explorer : News and analysis | ProMusa - the banana knowledge platform , this article led me to think that using velutina as a diploid mother and FHIA-01 as the pollen donor could potentially lead to the outcome I would like.

I was led to believe from an amateur plant breeding book that you could calculate how many offspring you would need to grow to have a 95% chance of expressing the desired traits? Is this not the case? Or just not the case for the elusive musa at this point in time?


I am starting to understand how difficult banana breeding has been and have no illusions that I will produce anything useful easily, but I would still like to try.

Regards

Sam

Sam g

I have not found specific information on the fertility of FHIA-01 but I did read in an article about pollen fertility that said something like; diploids have 3x more viable pollen than tetraploids & tetraploids have 3x more viable pollen than triploids on average. M.accuminata & M.balbisiana had 71% and 98% viability. Gros michel had the highest viability of tested triploids at 13%. I have read of doctor Greg Fonsah producing M.velutina interspecific hybrids also.

Sam g

From Frederic Bakrys article; "Where the two strategies part ways is in the energy they each invest in generating seeds, as opposed to evaluating hybrids in the field. One admittedly extreme example of the 3x/2x strategy was presented at the 2011 ISHS-ProMusa symposium. The breeders obtained 200 seeds, but only after hand-pollinating 20,000 plants. By contrast, Bakry and his colleagues harvested as many as 500 seeds from a single plant. Their main problem is lack of space to evaluate all the hybrids they could potentially produce. To be sure, not all of them are gems. For example, 6 of the 38 hybrids from a cross between Kunnan 4x and Musa acuminata spp. malaccensis were “non-parthenocarpic plants bearing seedless stunted fruits”. On the other hand, half of the progeny had a bunch weight superior to the one of either parent"

Richard

Then Namwa and Mysore are perfect for you, plus a few others. No need to breed anything.

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druss

This table below shows the vigor of various crosses, can't locate the paper it was from. It shows male acuminata on female veluntina as weak, but might be different with tetraploids.

druss

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Sam g

Thanks for that table Druss! Fantastic resource.

druss

Looked on crop diversity musa ascensions, it lists gold finger pollen as vitality absent.

Sam g

Thanks for checking druss, where would I find that information? It would be great if you have a link?

Sam

druss

druss

Thought I should update this, I was reading an article" Pollen fertility in Musa: Viability in cultivars grown in Southern Australia" by J. A. Fortescue A B and D. W. Turner A, This lists goldfinger as having 27% viable pollen. So it may well be good for what you want having AA or AB haploid Pollen.

Sam g

That's excellent information Druss, thanks! I thought I should give my first update; it seems that no one grows velutina here so I obtained seeds and have sprouted and potted up 10 so far with more sprouting every few days. So I just need to wait another year or two for the first pollination

imclumbi

Excellent. Where did you get the viable fresh seed?
Please post pictures of the seedlings progress!
John

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John

Sam g

I will have to get back to you about the seeds source, will need to look through my receipts.

As for the photo;

sorry about the sideways photo, I am using my phone to upload the image and can not seem to get it the right way up. The shoots just started appearing one week ago after being on the heat mat for about 5 weeks. It is mid spring here in Tasmania so it will be interesting to see how much they grow by the end of the warm season.

imclumbi

Awesome! Thank you and keep us posted!

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John

SoCal2warm

From what I understand, when you hybridize a diploid with a tetraploid, the result will be a triploid, and will be mostly seedless.

However, parthenocarpy is an additional genetic trait (which does not have to do with chromosome count). A banana that is both triploid and has parthenocarpic traits (for example the Cavendish group) would have virtually no seeds (if you went through an entire bunch of bananas you would not find a single seed in any of the fruits).

druss

If you cross a diploid and a tetraploid, you will generally get a triploid of varying fertility. The fruit will have varying amounts of seeds depending on pollination. Non parthenocarpic triploids will never be seedless as unfertilized fruit just dont develop. However if the plant carries the genes for parthenocarpy then itwill fruit irrespective of pollination.