Green tipped woronowii

[Martin Baxendale]

If virescens is caused by phytoplasma infection then I and other growers trying to raise new virescent snowdrops by crossing and back-crossing existing virescent snowdrops are wasting our time 

[johnw]

If virescens is caused by phytoplasma infection then I and other growers trying to raise new virescent snowdrops by crossing and back-crossing existing virescent snowdrops are wasting our time 

Carry on. It should soon become apparent and worth any effort.

johnw

[Martin Baxendale]

John, I'll still try back-crossing to see what happens in the second generation. It looks like it's either recessive gene(s) or phytoplasma that's involved.

[ChrisD]

At last here are a couple of photos(i hope?) of our green tipped woronowii.It is just a day or two from flowering this year,and this will be it's sixth year of flowering.This has been chipped,but it only makes pips not bulblets,so you will have to wait while for one of these.It is a hardy plant with me in north yorkshire and hope you all like it.

Oh yes Steve that looks very nice.

Chris

[KentGardener]

That is lovely Dimitri, I really like long petalled snowdrops and when they are swept up like that they are very attractive.

Indeed it is.

And Grumpy Steve - your green tipped is lovely too. 

It just goes to show that all the variation we see in nivalis and elwesii are most likely out there to be found in most species.

[johnw]

John, I'll still try back-crossing to see what happens in the second generation.

Martin / Anne

A bit of a diversion here, on the subject of back-crossing if you wanted to produce a large yellow would you for instance in the back-cross put Wendy's Gold or Big Boy's pollen back on (Big Boy x Wendy Gold)?  I've never been clear on that, I guess it wouldn't hurt to try both pollens on different flowers of the hybrid.

johnw

[Martin Baxendale]

You'd need to back-cross the Big Boy x Wendy's Gold seedling with pollen from Wendy's gold (and/or put pollen from the seedling back onto Wendy's Gold. The aim is to get two of the recessive yellow gene in the second generation. Wen dy's Gold should (as a yellow) have two yellow recessive genbes (yy) while thecross with Big Boy would just have inherited one yellow gene from WG and one green gene from BB (yg). When you back cross the seedling with Wendy's gold, you get yy x yg which will give you some yy and some yg. The yy second generation seedlings should be yellow.

If you back-crossed the seedling (yg) with Big Boy (gg) you'd get yg x gg = yg and gg. There would be no yy seedlings in the second generation so no yellows.

[johnw]

So would you have to be satisfied with at least one size down or worse from Big Boy in the first go at the back-cross?  Presuming I guess the large gene is recessive as well.

Where would (BB x WG) x sibling go? Or even [(BB x WG) x WG] x sibling. Lose size?

johnw

[Martin Baxendale]

I was just coming back to this to say that another route would be to inter-cross the BB x WG seedlings. You'd get fewer yellows but you would get some, and they'd have more Big Boy blood in them. The hybrid vigour from an elwesii x plicatus cross would also help. But any cross involving back-crossing with Big Boy would be unlikely to produce any yellows (unless Big Boy carried the recessive yellow gene naturally - in which case it would have shown up in the first generation, with yellows appearing in the F1s).

[Oakwood]

Dimitri, so basically the answer is that it's much more difficult for phytoplasmas to infect a plant than a virus, so that transmission of phytoplasma infection from one plant to another, through an insect vector or any other means of sap transfer, is much less likely to happen than transmission of a viral infection?
Yes.

So I could have a virescent phytoplasma infected snowdrop in my garden amongst other snowdrops for many years but the chances of that phytoplasma infection spreading to other snowdrops nearby would be quite low?
Yes, I suppose

Also, the chances of seedlings carrying the phytoplasma infection are low but not impossible, again because it's even less easy for phytoplasmas to be transmitted to seeds than for viruses to be transmitted to seeds (but again, not impossible).
Yes.

Yet yellow snowdrops will often produce yellow seedlings if crossed with other yellow snowdrops.
Should be proved, if it is due to simple Mendel genetics or to some stochastic infection transmission (virus, bacteria) in gametes then in seed tissues...

Virescent snowdrops, on the other hand, do not seem to readily produce virescent seedlings (from the results of seed raising by myself and others).
See first mention: it is difficult to transfer a pathogen trough seeds, so we obtain here mainly normal seedlings from virescent parent plants. We could try also simple intentional contamination I suppose the multiple weakened but not virescent plants, e.g. mosaic-virused plants, or frost-damaged plants, trough fresh sap injection and to wait for such virescence genesis in host plants with time...

I suppose you may be right about the possibility of virescens being caused by phytoplasma infections. With the yellow mark colouring, it still looks like something genetic is happening.

[Martin Baxendale]

Thanks for your comments, Dimitri. I agree with you  that it looks like phytoplasma infection could be a possible cause of virescens. If it becomes obvious through cross-pollination experiments that virescens cannot be induced genetically then of course it must be some other factor, most likely phytoplasmas as you suggest. About the yellows, I should have said that (because yellow seedlings can be produced by crossing yellows) it looks like something genetic MAY be happening, rather than IS happening. I agree that this still needs to be proved or disproved - the way yellows are produced from seed does not always seem to follow the basic Mendelian rules and some odd results can be had.

[Martin Baxendale]

To confuse things even more, it is in my experience possible to raise seedlings  from snowdrops with green TIPS to the outer segments and quite easily get seedlings which also have green tips. Obviously much more breeding work (and laboratory work) is needed to establish exactly what is happening.

[Alan_b]

But snowdrops are quite closely related to snowflakes (leucojum) and these always have green-tipped petals.  So surely it would not be surprising if there were a few genes for green-tipped outers swimming around in the gene pool?

[Oakwood]

But snowdrops are quite closely related to snowflakes (leucojum) and these always have green-tipped petals.  So surely it would not be surprising if there were a few genes for green-tipped outers swimming around in the gene pool?

Alan!))))) +5!!! Yes, these mutations (green tips outer segments, poculiformis, more than two leaves, twin flowers per stalk, etc.) just reflect the common ancestor in the past for Leucojums and Galanthus)))

[Martin Baxendale]

That's what I was wondering - if green tips are more likely to be purely genetic since they do seem to be an inheritable characteristic. Or whether they could also be caused by phytoplasma infections. If they are inherited from parent to seedling then it looks like genetics. But sometimes green tips and stripes are not inherited by the seedlings, and sometimes snowdrops will have green tips or stripes one year and not in other years. And what about the partial virescens of snowdrops which don't just have green tips but aren't totally virescent, with a number of green markings, like 'South Hayes' (which also tends to lose its green markings when twin scaled - which could indicate a phytoplasma infection which is 'cleaned up' by twin scaling). It might be difficult to establish a hard and fast rule that virescens may be due to phytoplasma but green tips are always genetic. It could be one cause in one snowdrop and the other cause in another snowdrop. Each case would have to be investigated individually.