It is a little bit technical for me but it is interesting;

Triploids from Small Seeds of Polyembryonic Citrus Cultivars

There is a long list of polyembryonic citrus varieties.

Best,

Thanks for the document!

Okay, somebody help me out with this please.....

Just a couple of days ago, I collected the seeds from 4 Sunburst Tangerines and there were about 55 of them. Of these I save only the largest of the seed to germinate. Now I am confused on how to identify which ones to cull when they sprout.

If I am reading this article right, the largest seeds produce diploids, is that right? Does (large seed) =diploid =monoembronic?

I know they are saying (small seeds) triploid=seedlessness---a very desirable trait for commercial purposes.

They also say triploid seedlings from small seed grow much slower for the first two-three years then begin rapid growth.

How does this come into play when determining which seedlings are 'coming true'? How are the nucellular seedlings identified?

When I make the culls on my seedlings, how can I be sure I am keeping the seedlings true for 'Sunburst'?

After reading many of the posts already dealing with this issue, I find
that I am not clear of how to make the right determination. Thanks for bearing with me.

Sunburst Tangerines is a poly embryonic variety, therefore the seed will produce true to type. In poly embryonic varieties the zygote is normally crowded out by the nucellular embryos and killed. However, there is always a very small chance that a zygote could survive and will produce a seedling that is not be true to type. However, if you plant 6 or 7 of your seeds and if one is different the the rest, that one will be the zygote. However, I doubt that you will find any zygote seedlings. - Millet

Citrusgalore, You are mixing three different things, true-to-type-ness , mono/polyembryony and ploidy.
Ploidy:
- Citrus have 9 different chromosomes.
- only gametic cells (the one for reproduction) have 9 chromosomes.
They are said aploids (1x9).
- "normal" (somatic) citrus cells have 2x9 chromosomes (18 ). They are said diploids.
- The triploids citrus have 3x9 chromosomes in each cell.
- The tetraploids citrus have 4x9 chromosomes in each cell. And so on...

- For "mecanical" reasons, diploids and triploids cannot cross, that's why they are seedless.

Sylvain.
P.S. But triploids could cross with triploids, leading to a true new species... Interesting!

So then...
How many chromosomes are in the gametic (sexual) cell of a triploid.
In other words- how does it split?

Kyle

Yes, you're right. There are issues during the meiose. And they must be sterile.

But what I said is true for tetraploids.
Tetraploids could cross with tetraploids,leading to a new true species.

And indeed, (what we already discussed on this forum) tetraploid can cross with a diploid giving a sterile triploid (seedless).

Sylvain.

Okay I got it now...I had to go back and read it again....tks for clearing it up.