Theo Sanders, Germany

Pollen Volume and Chromosome Content of Daffodils; Possibilities for hybridizing 2 and 3

January 12, 2014

Categories: Fertility, Hybridizing, Pollination, Science

Download PDF

During  March 2013  I found some different yellow bulbocodiums in Potugal and Spain. From observing the pollen volume I think that four plants are diploid, two are tetraploid, and one is hexaploid. I found out that most diploid species can easily be crossed with fertile jonquilla hybrids like Hillstar and fertile viridiflorus hybrids like Emerald Sea. This is also true for a diploid bulbocodium of the Sierra Madrona and a diploid cantabricus from the Sierra Calatrava. These crosses should be possible too with the new four diploid plants.

Daffodils and other flowering plants are fertile when the number of the chromosome sets can be devided by two and this gives a whole number. Therefore Silver Bells (NNTr) and Beryl (CyPoPo) should be infertile. Nevertheless they form some fertile pollen which are NTr for Silver Bells and in most cases CyPo for Beryl. Fertile pollen can be found too for the NNNJ plants Cool Pink, Harpsichord, Clavichord, Magic Step, and Problem Child. Perhaps I can inspire some other hybridizers to try their pollen in this spring. There are many interesting possibilities for crossings.

Similar is the Situation for XXYZ plants, for example crosses of  jonquilla hybrids with viridiflorus hybrids. Many of  these generate  fertile pollen.

Some more  information concerning this theme you can get from the document ‘Pollen Volume and Chromosome Content of Daffodils – Possibilities for hybridizing  3’  of  my internet site ‘’ .


7 responses to “Pollen Volume and Chromosome Content of Daffodils; Possibilities for hybridizing 2 and 3”

  1. Clay Higgins, New Jersey Clay Higgins, North Carolina says:


    I have actually made that cross with N. herriquesii X unknown yellow bulbocodiums thought to be in the romieuxii category.  In the first year of bloom I took it to Gloucester and showed it to Brent Heath.  The first year it had two small looking Div 10 style blooms (hoop petticoat) on it one above the other.  However, since them it has bloomed as a single head Div 10.  I dug in in 2013 as it was not increasing by bulb division and replanted it in the fall. It also is sterile. I will be watching it again this spring to see what it does, if anything. I’m not happy that it does not increase, but makes fairly large bulbs.


  2. Mary Lou Gripshover, Ohio Mary Lou Gripshover, Ohio says:

    Theo, thank you for posting the information about your website.  We have also posted your articles on under Science, Hybridizing.  One is also posted under Science, Cytology.  Thank you for making this information available to all. You have bred some amazing seedlings.

    Mary Lou

  3. Clay,

    It seems to be easier to cross bulbocodiums with higher ploidy level with the species N. jonquilla than with jonquilla hybrids (NNJJ). In DaffSeek you find many  N. bulbocodium conspicuus (hexaploid) x N. jonquilla crosses. The flower stems in most cases have one flower only. By the combination with tetraploids or diploids the influence of N. jonquilla should be intensified.


  4. Larry Force, Mississippi Larry Force, Mississippi says:


    Thanks so much for your work and dedication in your daffodil fertility and hybridizing trials. And of course, making this work available to hybridizers and would be hybridizers out here in daffodil land. Your work truly does inspire us to try new and different things. Nothing ventured nothing gained.  Thanks again from all of us out here in daffodil land.



  5. Clay Higgins, New Jersey Clay Higgins, North Carolina says:


    Usually people think I’m a “wise acre” because of some of my postings and answers on Daffnet.  But from my stand point I am just stating the obvious as I see it:  No insult intended.

    I started my hybridizing program back in the good old 1990 somethings.  I guess no one gave me a book to read on hybridizing so I was using available sources within my garden.  I made a lot of what could be caused “weird” crosses because I had “no one” to teach me.  It has given me many crosses that I have used in shows to complete collections like the Premiere Award in 2013 that I would not have been able to do using only commercial available miniature specimens.

    If I hadn’t started an intense email correspondence with Graham Fleming years ago on hybridizing I’d still be lost.  My hybridizing had become more focused since my early days.  I really like some of the stuff I’m doing these days.

    Thanks for all your work and dedication as well as the work and dedication of others who post valuable information about fertility, hybridizing, and families of species that help me decide what species are related to what others on Daffnet.  Thanks also to those that write books such as James S. Wells and other.

    And thanks daffnet for no longer being an email only media.

    For what it’s worth,



  6. Lawrence Trevanion, Australia Lawrence Trevanion, Australia says:

    Thanks Theo. Interesting and helpful as always.

    When writing about intersectional hybrids you write: “for individual chromosomes the exchange of genetic material by crossing over during the reduction division cannot be excluded.”

    I think it is clear that this is definitely happening in crosses between tazettas (2n=20) and paperwhites (2n=22) – although these have traditionally been regarded as belonging to the same section. I have a strong suspicion it is happening in the main division / bulbocodium hybrids. Obviously it is happening between the narcissus (poets) and pseudonarcissus (trumpets) sections – to such an extent that one wonders how significant the fertility barrier between these two sections actually is. Diploid poet x cyclamineus and poet x alpestris both have fertility (although the poets I used were cultivars and not species). I think you are right to guess that Beryl is 2 parts poet and 1 part cyclamineus but for me the extent to which it can pass on a distinct set of cyclamineus and poet chromosmes (PoCy) is an interesting question. If Beryl selfed to produce an exceptionally fertile tetraploid intermediate between poet and cyclamineus the question would be settled. But I have no idea what number of seedlings would be needed and what the survival chances of such a seedling would be.


  7. Lawrence,

    I think to self Beryl is a very good idea. You get fertile descendants if the egg cell has PoCy chromosome sets as well as the pollen. The probability for this seems to be high. A similar result should develop from selfing Articulate and Jetfire. Perhaps Straight Arrow (Jetfire open pollinated) is already such a result.