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Sam g
06-03-2018, 12:36 AM
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
06-03-2018, 02:37 PM
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.

druss
06-03-2018, 05:30 PM
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
06-03-2018, 05:32 PM
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 (http://www.promusa.org/blogpost299-Banana-breeding-s-explorer) , 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
06-03-2018, 05:46 PM
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
06-03-2018, 05:56 PM
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
06-03-2018, 10:58 PM
... we have zones 9b and 10a here ..

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

druss
06-03-2018, 11:16 PM
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
06-03-2018, 11:23 PM
http://www.bananas.org/gallery/watermark.php?file=63134&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=63134)

Sam g
06-04-2018, 12:09 AM
Thanks for that table Druss! Fantastic resource.

druss
06-14-2018, 08:18 PM
Looked on crop diversity musa ascensions, it lists gold finger pollen as vitality absent.

Sam g
06-15-2018, 06:37 PM
Thanks for checking druss, where would I find that information? It would be great if you have a link?

Sam

druss
06-15-2018, 06:43 PM
https://www.crop-diversity.org/mgis/accession/01AUS0434

druss
07-27-2018, 06:22 AM
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
10-17-2018, 05:45 PM
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 :ha:

imclumbi
10-17-2018, 06:32 PM
Excellent. Where did you get the viable fresh seed?
Please post pictures of the seedlings progress!
John

Sam g
10-17-2018, 09:02 PM
I will have to get back to you about the seeds source, will need to look through my receipts.

As for the photo;http://www.bananas.org/gallery/watermark.php?file=63988&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=63988&ppuser=27417)

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
10-18-2018, 05:48 AM
Awesome! Thank you and keep us posted!

SoCal2warm
10-27-2018, 09:54 PM
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
10-28-2018, 12:08 AM
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.

SoCal2warm
10-28-2018, 12:27 AM
Non parthenocarpic triploids will never be seedless as unfertilized fruit just dont develop.
Admittingly, I'm not sure exactly how it works in bananas, but in triploid citrus fruits will certainly develop, it's just that those fruits will be "seedless" because nearly all the seeds will fail to develop.

(even when the variety requires pollination to set fruits, and this only applies to non-nucellar citrus varieties here which do not produce true to seed)

Gabe15
10-28-2018, 02:15 AM
druss is correct on this, seedlessness and ploidy are not directly related. You could theoretically have a seedless, non parthenocarpic triploid in which the fruit do not develop.

The seedless citrus are still parthenocarpic, their lack of seed does not automatically mean the plant will form a seedless fruit. The act of forming a fruit still needs to be initiated and is genetically controlled. Normally in wild plants, when the ovules are fertilized after pollination, the growth of the young seeds trigger the fruit to also start growing. If no seeds develop, and the plant does not have another mechanism (parthenocarpy) to trigger fruit development in the absence of pollination/fertilization, then you would just be left with a withering nub of a potential fruit that will never grow.

It is an incorrect oversimplification to conclude that triploidy causes sterility which leads to seedless fruit. In the case of bananas, triploidy often lowers fertility and potential seed set, but it is parthenocarpy that allows a potentially seedless fruit to develop. Even parthenocarpic triploids will often set some amount of seed when pollinated however, just typically not as much as the most fertile diploids and tetraploids. And there are many reasons for sterility, not just ploidy level. There are sterile diploids, and fertile triploids as well.

SoCal2warm
10-28-2018, 06:07 PM
druss is correct on this, seedlessness and ploidy are not directly related.
Isn't it true that all eating quality banana varieties are triploid cultivars?

That would seem to imply triploidy has something to do with seedlessness...

druss
10-29-2018, 12:28 AM
No, there are plenty of good eating quality bananas of diploids, i.e nine enano, inarnibal, terema, sucrier etc plus plenty of good tetraploids such as the fhia lines like goldfinger, plus other synthetics like calypso. Its true wild tetraploids are rare but they are around, from memory Gabe identified one on bouganville.

druss
10-29-2018, 02:34 AM
Gabe, do you have a preference for method of hand pollination?

Gabe15
10-29-2018, 11:47 PM
Isn't it true that all eating quality banana varieties are triploid cultivars?

That would seem to imply triploidy has something to do with seedlessness...
Definitely far from the truth. There are innumerable edible diploids, and in fact they are arguably the most diverse class of edible bananas.

No, there are plenty of good eating quality bananas of diploids, i.e nine enano, inarnibal, terema, sucrier etc plus plenty of good tetraploids such as the fhia lines like goldfinger, plus other synthetics like calypso. Its true wild tetraploids are rare but they are around, from memory Gabe identified one on bouganville.
We found two in Bougainville, but there are definitely a few others out there as well. And yes of course, many many synthetic tetraploids exist from breeding programs.

Gabe, do you have a preference for method of hand pollination?
I have mesh bags I put around the male buds to prevent pollen contamination. I collect newly opened male flowers from the bagged buds early in the morning, usually around 6-7AM, then immediately use them to pollinate female flowers on other plants. If they are small female buds, you can also bag them to prevent insect or bird pollination, or you can pollinate the hands that are a day or two out from opening by gently lifting the bract, manually opening the female flowers to expose the stigma better, pollinating, and then closing the bract back over it, it kinda acts like a natural bag well enough.

If I'm working with highly fertile males with lots of pollen, its easy to basically use them like little paintbrushes on the stigmas. If there is not very much pollen, I sometimes slide the male flower over the stigma so that the anthers come in direct contact with the stigma along their entire length, thus getting more pollen.

In some male parents with very little or no visible pollen, you can sometimes still get some by gently scraping the anthers with a toothpick to manually open them and get a little bit of pollen on the toothpick which I then use to transfer to the stigmas of the female flowers.

Richard
10-30-2018, 01:00 AM
... in triploid citrus fruits will certainly develop ...

Yes. But you need to take a step back, read the publications of my forefather Howard Frost, and try again.

University of California: In Memoriam, December 1970 (http://texts.cdlib.org/view?docId=hb629006wb&doc.view=frames&chunk.id=div00015&toc.depth=1&toc.id=)

druss
10-30-2018, 01:01 AM
Excellent, it appears that i will have a musa zebrina with male flowers at the same time as a goldfinger with female, think the goldfinger is female sterile but will practise anyway.

SoCal2warm
10-30-2018, 11:53 PM
Apparently there are two different levels of causes for seedlessness.
Hybridization between different species, and triploidy.

Wild bananas produce tiny fruits filled with hard, inedible seeds and little fruit flesh. The plants are diploid, that is, they have two copies of each chromosome – just like humans.

When people moved from one island to another, they brought so-far isolated banana subspecies into contact. Occasionally, two subspecies would spontaneously hybridize. To the early banana farmer’s great delight, some of the diploid hybrid bananas produced less seed and more delicious fruit flesh. On the downside, the hybrids had also lost a great deal of their sexual potency. However, bananas can easily be propagated from suckering shoots and the hybrid’s partial impotence did not dull the banana farmer’s joy about its rich fruit flesh.

Eventually, the banana evolved into its present maiden-like parthenocarpic state after another hybridization event. Through a phenomenon called meiotic restitution, the partially sterile hybrids mated to form triploid bananas (e.g. carrying three copies of each chromosome) with large, seedless fruits of an unheard-of sweetness.
https://bananaroots.wordpress.com/tag/wild-banana-species/

Richard
10-31-2018, 12:34 AM
Apparently there are ...

You might want to follow Gabe15's education path to get up to speed.

druss
10-31-2018, 01:10 AM
Less seed and more flesh is not the same as seedless or parthenocarpic. This overview is incomplete It doesn't mention the initial subspecies of acuminata behind the initial edible bananas, then crossed with balbisina to give rise to new varieties though no true edible bb, bbb or bbbb exist. nor does it explain the fact that african edible bananas are from possibly a different domestication event. It fails to address the other interspecific hybrids like AS vunamami and ones with callimusa such as umbubu AAT or Yawa2 ABBT a three species 2 subgroup hybrid. Also for a long time ploidy was a judgement call, only now with flow cytometry can we know if assumed genetic id was right. Id work on the traits you want and let the ploidy sort itself out.

Gabe15
10-31-2018, 01:34 AM
Apparently there are two different levels of causes for seedlessness.
Hybridization between different species, and triploidy.


https://bananaroots.wordpress.com/tag/wild-banana-species/

If you really want to begin to understand what you seem to want to know, start here:
https://www.abebooks.com/servlet/SearchResults?sts=t&cm_sp=SearchF-_-home-_-Results&an=simmonds&tn=the+evolution+of+the+bananas&kn=&isbn=

Gabe15
10-31-2018, 01:44 AM
Apparently there are two different levels of causes for seedlessness.
Hybridization between different species, and triploidy.


Hybridization aided in increasing diversity, and triploidy tends towards more vigorous and larger plants, but neither are directly related to seedlessness/edibility.

Seedlessness is a condition, not a trait. A plant may or may not be seedless depending on if it was pollinated or not by viable pollen. You can't tell if a banana is incapable of making seeds unless it is properly pollinated. The fact that you don't finds seeds in a given edible banana fruit doesn't really mean much as to whether or not it has the capability to produce seeds under the right conditions.

One of the most notorious seed setters among edible bananas are many members of the Pisang Awak subgroup, which are hybrid derived triploids. If pollinated, they can make so many seeds that it can really get in the way of eating the fruit normally.

druss
11-05-2018, 11:09 PM
Slightly off topic, but Gabe I can only access the male flowers on the donor plant between 8sm and 5pm, can i pollinate in the evening? Or will the male flowers last until morning?

Gabe15
11-06-2018, 03:16 AM
Slightly off topic, but Gabe I can only access the male flowers on the donor plant between 8sm and 5pm, can i pollinate in the evening? Or will the male flowers last until morning?
Try as early as you can, 8AM will probably still work, but pollen viability decreases as the day goes on. It is best to collect the male flowers and pollinate right away, if you have to wait, I would collect the male flowers and refridgerate them soon after planting, then pollinate the female flowers in next morning.

druss
11-06-2018, 05:18 AM
Awesome thankyou, i dont anticipate any success with this cross but need to start practicing the mechanics.