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DoctorSteve 06-17-2010 10:14 PM

Seeds in my bananas
 
I have a question. So what is up with those small seeds I find in bananas sometimes? Do they produce seeds even if they are not fertilized?

Gabe15 06-18-2010 01:40 AM

Re: Seeds in my bananas
 
Basically, edible bananas do not produce seeds. Those little black things are the undeveloped ovules, not seeds. Bananas are propagated asexually. There are bananas with seeds, but thats not what you are seeing.

DoctorSteve 06-18-2010 08:08 AM

Re: Seeds in my bananas
 
Hey thanks Gabe. That is what I thought they might be but I wanted to keep my question short. I am not that familiar with plant biology yet but I was thinking along those lines. So if they were fertilized the seeds would be bigger I am guessing? For example the cross pollination efforts by FHIA.

Gabe15 06-18-2010 12:16 PM

Re: Seeds in my bananas
 
Well, essentially yes, if they were fertilized they would become seeds about the size of peppercorns, but this is not so straightforward. In the case of the ones you are likely thinking of (normal store bought bananas), no, they will never become seeds because the plants are completely sterile, but in other varieties it is possible.

DoctorSteve 06-19-2010 02:21 PM

Re: Seeds in my bananas
 
I see, well I guess in my readings and research I will find out which are and which are not able to fertilize or be fertilized. I would like to try coming up with my own variety/s even though I understand it is hard and time consuming. I know Rowe tried for many many years but and had few results. I think we should all try, hundreds or thousands of us just tinkering with banana breading. The number of different combinations of shuffled genes is massive. If we all play with it we may find some cool stuff.

Gabe15 06-19-2010 03:40 PM

Re: Seeds in my bananas
 
Rowe and his team (he was not alone, and was not the first or last banana breeder either) were very successful, there are a number of varieties that come from the FHIA breeding program which are currently in use. Breeding bananas is actually quite easy, the difficult part is breeding bananas that are good enough to then be adopted and utilized in various situations. It is relatively easy to create new plants, its just getting those plants to be what you want them to be where the difficulty often comes in.

island cassie 06-19-2010 05:30 PM

Re: Seeds in my bananas
 
Thanks guys!!! In the early days when I found an edible banana with thin papery seeds, I got all excited!! Now I know better, but it is good to know I am not alone!

DoctorSteve 06-19-2010 11:58 PM

Re: Seeds in my bananas
 
Yeah I guess that is true. The book I read made it sound like breeding bananas was hard. To be fair they did have many requirements for the bananas they had to meet. That combined with the fact that it was 20 years ( I think, correct me if i am wrong) before they came up with the goldfinger mad it seem hard. So Yeah we could come up with other varieties I guess but they may not meet FHIA standards. My requirement is that it must be yummy.

Thanks for the help Gabe. I am very happy with the way everyone acts on this forum. Everyone seems to be very mature and helpful.

Glad my little question could help you island cassie.

Gabe15 06-20-2010 07:04 AM

Re: Seeds in my bananas
 
Breeding any crop is difficult, you take two plants which look good, put them together and who knows what will come out. What makes breeding bananas more difficult than say, maize, is that bananas take about a year to flower, and so to see one hybrid through, from planting the parents, doing the cross and raising the progeny to maturity may take up to 3 years. Maize in Hawaii can go through 4 cycles in a year, 4 cycles in banana could take 10 years. Bananas are also relatively large plants which require a lot of space, which means a lot of land that rarely comes cheap. Compare the space needed for 1000 maize plants (10 rows of 100 plants at 1ft spacing) to the same needed for banana at a 6ft spacing, it adds up quick! Additionally, bananas are a crop based on the absence of seed, and breeding is based on the presence of seed, so some interesting challenges can arise with that to further slow the process. However, bananas are relatively quick if you compare it to the breeding of tree crops which may take 15 years or more to flower from seed. So it's all relative.

What I mean by my previous statements is that, if you have the right parents and facilities (a tissue culture lab is highly useful for embryo rescue since even normal wild banana seeds are difficult to germinate, and the edible hybrids are normally far worse), producing progeny is not that difficult. But the time and resources required to sort through that progeny, evaluate a number of cycles, and do further breeding if necessary to find what you are looking for is very time consuming compared to most common staple crops such as maize, wheat, rice, tomatoes, leafy greens etc...

Mostly its an issue of time, and a lot of breeding work in bananas is focused on reducing the amount of time it takes to evaluate hybrids. One of the technologies of high interest is marker assisted selection, whereby a breeder is able to detect a specific gene that must be transferred, and so plants can be screened even when very young for the presence or absence of that gene. This of course has its drawbacks too, such as missing out on a potentially very useful new trait that would have only showed at flowering, but that's an example of the kind of work that is being done.

DoctorSteve 06-21-2010 12:23 AM

Re: Seeds in my bananas
 
Thanks Jeffrey that is very interesting.

Gabe15 06-21-2010 03:38 AM

Re: Seeds in my bananas
 
That is mostly true Jeffery, except that in bananas parthenocarpy and ploidy level are unrelated, and parthenocarpy can be present in diploid, triploid and tetraploid varieties. Sterility in bananas come form other, non-ploidy related meiotic errors and mechanisms such as pollen tube growth inhibition. There are extremely sterile parthenocarpic diploids, as well as extremely fertile parthenocarpic triploids. Nearly every combination and degree of ploidy level, sterility (of both gamete types, male and female) and parthenocarpy is present in at least some varieties. Many banana varieties, even triploids, can in fact set seed if pollinated. This is why banana breeding is possible.

One way to think about it is this: the growth of fruit is normally triggered by the fertilization and growth of seeds within the fruit. If a banana were to be completely sterile due to triploidy or any other source of female sterility, and thus could not form seeds, then how is the fruit still able to swell and develop? The answer is vegetative parthenocarpy, in which the hormone release promoting the fruit to develop that would normally be associated with the growth of seeds is replaced and executed by an autonomous action. Parthenocarpy is completely separate from anything else, and it even occurs in wild populations of banana, which is how they were first domesticated.

jeffreyp 06-21-2010 05:20 AM

Re: Seeds in my bananas
 
it is possible to get seeds absolutely and here's a good article below. Gabe, my understanding was bananas were sterile and seedless because one set of chromosomes (A or B) has no homologous set to pair up with during synapsis of meiosis?
Plant Breeding Reviews - Google Books
http://www.ias.ac.in/jarch/jgenet/43/337.pdf

Gabe15 06-21-2010 10:58 AM

Re: Seeds in my bananas
 
Quote:

Originally Posted by jeffreyp (Post 132185)
it is possible to get seeds absolutely and here's a good article below. Gabe, my understanding was bananas were sterile and seedless because one set of chromosomes (A or B) has no homologous set to pair up with during synapsis of meiosis?

Yes, that is a commonly perpetuated myth about bananas, even among otherwise reputable resources. It is easy to say that they are seedless because they are triploid, but it just isn't true, at least in the case of bananas. The way they are able to still breed is partly by the creation of unreduced gametes, so instead of trying to divide 3 in half, it just keeps it as 3 and with another haploid gamete thrown in the mix you can create tetraploids. Triploids likewise can be produced by crossing a normal diploid (with haploid gametes) with a diploid which produces unreduced (2n) gametes, or by crossing a normal reducing diploid with a normal reducing tetraploid. However, as is often the case with bananas, even that is not so simple sometimes, and in practice when doing banana breeding, everything from 2n to 4n (and beyond soemtimes) can be produced from nearly any cross involving a parthenocarpic plant, there are still some mysteries of exactly how meiosis works in edible bananas in some cases.

jeffreyp 06-21-2010 12:13 PM

Re: Seeds in my bananas
 
ok...thanks for the info...much appreciated.


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