Quote:
Originally Posted by whynot
Maby it's just my lack of a banana genetics background, but I thought tetraploids were the common basis for generating triploids. I understand that they have low fertility but I should get a few seeds if I try a huge sample with an acceptable diploid parent, right? When I look at the crosses used to develop the triploids, I see a number of crosses with a triploid parent. Wouldn't tetraploid actually be more a more fertile parent? I know it diverges from my first question a bit, but if the tetraploids are basically mules, would trying to induce polyploidy via colchicine give me potential seedless/rarely seeded fruit? Ben
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Ben,
My advice: Don't waste time with tetraploids.
Use male fertile or female fertile cultivar bananas - preferably ABBs-in conjunction with cold hardy wilds of the
itinerans and
basjoo groups.
You could start with ABB "Orinoco" - it is sparingly fertile. When crossed with wild
balbisiana pollen, you might get 10 or more good seeds per bunch. The reciprocal cross - female
balbisiana and Orinoco pollen might be even better. I haven't performed this cross - yet.
You'll have to harvest pollen at twilight or later.
If on growout of seeds (you'd need about 100 good seedlings) you're lucky to get a diploid offspring that's parthenocarpic and male and/or female fertile -you've begun your journey.
You'd have captured the p1 gene in your recombined "balbisiana".
Keep backcrossing to
balbisiana to gradually eliminate as much
acuminata that you can and select to keep the parthenocarpy and large fruit.
You can then try to use pollen from a hardy basjoo or itinerans on the diploid parthenocarp.You might end up with an interesting diploid or tetraploid...
You're looking at 10-15 years.
You can try to shortcut by using hardy vars of
basjoo or
itinerans pollen on Orinoco or, better, using the reciprocal cross. I really prefer using wild diploid females - they are lots easier to work with. however, I have never performed those crosses.
You might get some immediately useful triploids in the first batch.
As an important aside; I don't think people in cold areas should look solely at cold hardiness. Look at an ultra short growing cycle - as happens with velutina. Which does cross with balbisiana.
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Currently I'm using Orinoco/Bluggoe; Saba & Pelipita ABBs to make large fruited parthenocarpic diploid
balbisiana for tropical banana growing & processing on degraded lands.
sdc