A germination question

[WNOETULIP]

Many years ago when Wendy started growing daffodils I remember reading several articles which suggested that when making a cross between two cultivars, the choice of which to use as the seed parent and which as the pollen parent was highly significant. Using cultivar A  instead of B as the seed parent would guarantee for example a much greater number of progeny which were of Division 1 proportions than if it was used as the pollen parent. Later I listened to (and read) Peter Brandham decrying this and saying that it made no difference since in both ways half the chromosomes from each of the parents were present in the progeny irrespective of the choice of seed parent. However can anyone explain the following, or perhaps direct me to the source of a written explanation.
For the past five years I have been crossing narcissus species to get miniature cultivars. I keep detailed records of when the seed emerges and then in subsequent years the date when the shoots emerge through the soil. All the crosses are grown in an unheated greenhouse. In 2014 I made a number of crosses between a very vigorous Narcissus bulbocodium which I had found at Baragem de Santa Luzia and Narcissus lusitanicus also from Portugal. The crosses were made both ways on the same day. The seeds were planted in identical pots, in the same mix of compost and have been grown in the same bed in the greenhouse. The three pots of seed with Narcissus bulbocodium as the seed parent started to germinate on the seventh, tenth and fourteenth of November (remarkably consistent). Two pots of selfed Narcissus bulbocodium germinated on the fourth and twelfth of that month. Two months later there is no sign yet of germination of the two pots where Narcissus lusitanicus was the seed parent. I am not particularly concerned since none of my triandrus crosses have yet germinated, though Narcissus lusitanicus is a very early flowerer and flowering size bulbs are almost ready to burst their buds.
Question? If as Peter Brandham alleges there is no difference between the progeny whatever the seed parent, what is the mechanism that allows the seed to remember which was the seed parent? Will the two different progenies flower at the same time?

[François Lambert]

I'm not an expert and have never made crosses intentionally myself, but I have read something about plants keeping track of their growing environment through parts of the DNA that is activated or not and that this information to grow better in a different environment is transmitted to the seeds resulting in better adaptation to the local growing conditions for the progenity.  This may explain why seedlings can be more vigorous than the original plant grown in a new location.  Assuming this is transmitted only to the seeds on the plant they grow on (receiving the chemical signs through the sap of the plant perhaps) this may be part or a begin of the explanation.  I have also read somewhere (but the source may not be so thrustworthy or correct) that crosses always ressemble a bit more to the seed parent than to the pollen donator.

[rob krejzl]

Look at the introduction here, http://www.ncbi.nlm.nih.gov/pmc/articles/PMC535866/, for a list of parent of origin effects on phenotype which might explain the proportion of Div 1 offspring. Obviously a very complex subject.


edit by maggi to remove stray comma in link!

[WNOETULIP]

Thank you very much Rob.
Unfortunately I had difficulty in accessing the link because there was a stray comma but I eventually sorted it out. It should have read http://www.ncbi.nlm.nih.gov/pmc/articles/PMC535866//
I am not a botanist and it will therefore take me some time to fully understand what is written in the article. However it is clear now that what I have observed is a parent-of-origin effect, I should not be too surprised because I am well aware of difficulties many hybridisers have had when using Narcissus triandrus as a seed parent in transferring desirable (from an exhibitor's point of view) characteristics such as corona colour from the pollen parent to the progeny. Far too often all that results is very much another very slightly different Narcissus triandrus. I will try and get access to some of the other research quoted in the article.
James

[rob krejzl]

Maggie,

Thanks for the edit - I was careless.

I was thinking about this general topic myself after listening to Judith Freeman at the weekend. She touched on the Triploid Block, so I started reading. Synchronicity.