Author Topic: Orange Pollen: is it sterile ?  (Read 258 times)

orangedays

  • Member
  • ***
  • Posts: 26
    • East Coast, Zone 8a
    • View Profile
Orange Pollen: is it sterile ?
« on: March 15, 2021, 07:11:38 PM »
I have read a couple of sources that state that oranges have sterile pollen. I have a Hamlin orange and an Amber-sweet just starting to bloom. The anthers look plump and yellow but I have not seen them shed pollen yet. Does anyone have experience with pollen and these two oranges?

Galatians522

  • Sr. Member
  • ****
  • Posts: 314
    • Florida 9b
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #1 on: March 15, 2021, 10:12:21 PM »
Hamlin is often planted in solid blocks in the commercial groves (sometimes a mile or more from any other citrus) and I have never noticed any polination issues. Actually, Hamlins tend to bear heavier crops than Valencia (when not affected by HLB) which would indicate better pollination to me if anything. I don't know much about Ambersweet because it has not been planted much around here. If my memory is correct, though, it has some Tangelo parentage (Orlando). A lot of Tangelos need cross pollination to produce their best crop, so pollination might be a concern there. With your Hamlin also blooming, though, I don't think that it will be an issue for you.

Ilya11

  • Hero Member
  • *****
  • Posts: 758
    • France, Paris region, Vaux le Penil, middle of Northern z8
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #2 on: March 16, 2021, 09:18:07 AM »
Most of oranges with an exception of navels have fertile pollen.
Best regards,
                       Ilya

pagnr

  • Member
  • ***
  • Posts: 49
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #3 on: March 16, 2021, 05:06:16 PM »
I thought the issue was that they are genetically triploid i.e. 3 sets of chromosomes 3N,  not diploid ( 2 sets, 2N ) which is the usual arrangement with most living things.

When the haploid ( 1N ) pollen is made from half set of the triploids chromosomes, the triploid plant makes  pollen with an odd set of chromosomes.
These are "sterile" because the chromosomes can't successfully combine with the set in a recipient ovule.

SoCal2warm

  • Hero Member
  • *****
  • Posts: 1411
    • zone 10 and zone 8a
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #4 on: March 16, 2021, 07:57:28 PM »
Pollen from triploid varieties does have reduced fertility, yes, but it can still pollinate things. A fraction of the pollen from triploid varieties will still turn out to be normal haploid pollen, just like from any other normal variety. Of course, if you're only concerned with pollination for fruit set, this doesn't matter as much. We have discussed this in other threads.
There are other genetic causes to sterile pollen besides chromosome number. (And not all seedless varieties of citrus are triploid)

From what I know, orange pollen is generally not sterile.

orangedays

  • Member
  • ***
  • Posts: 26
    • East Coast, Zone 8a
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #5 on: March 17, 2021, 09:43:08 AM »
Thanks for all your feedback. I am glad to know Hamlin is normally pollen fertile.  I am planning some crosses to changsha and to a citrumello. I don't have a lot of hope for the citrumello as mother, since its so polyembryonic. But I will try and see if anything comes of it.

Ilya11

  • Hero Member
  • *****
  • Posts: 758
    • France, Paris region, Vaux le Penil, middle of Northern z8
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #6 on: March 17, 2021, 02:59:19 PM »
I am not aware of any triploid varieties of true oranges.
Best regards,
                       Ilya

Galatians522

  • Sr. Member
  • ****
  • Posts: 314
    • Florida 9b
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #7 on: March 17, 2021, 10:00:37 PM »
I am not aware of any triploid varieties of true oranges.

Thank you. I was thinking the same thing. The only triploid citrus I could think of (not that they are the only ones in existence) were experimental tangerines being worked on by UF.

orangedays

  • Member
  • ***
  • Posts: 26
    • East Coast, Zone 8a
    • View Profile
Re: Orange Pollen: is it sterile ?
« Reply #8 on: March 22, 2021, 12:21:38 PM »
Pollen update. The Hamlin orange is releasing pollen now. The Amber Sweet anthers turn yellow but so far I haven't observed any pollen releasing in the open flowers. I read the anthers can be dried under a heat lamp and crushed to release the pollen, and this does seem to work for the Amber Sweet as I see a yellow dust against the glass container holding the pollen.