high percentage yellow cotyledons

I’m getting good germination the last few days from OP hips of Blueberry Hill. A majority look normal. But, around 30% of them are light yellow, with not even a hint of green. None have true leaves yet, so I don’t know if they may outgrow this condition. The root stems are a similar red-pink to the “normal” BH seedlings. None of my other seeds in the same planting mix (perlite/coir/vermiculite) are doing this. Have you seen something like this before, or can you help me understand it?

Thanks, jcr

I do not remember whether I had a number of yellow open pollinated Blueberry Hill seedlings or not. I do remember that most of mine did not survive (even among those that grew enough to be planted outside).

Joel, most of the yellow ones will turn out to be albinos. Some will produce a green first true leaf and will survive. Those that don’t will die.

You will see this more often in certain crosses. I have noticed it more in self or open pollinated seedlings presumably due to a recessive trait being expressed.

Jim Sproul

Thanks Jim, that’s interesting. Henry, what do you mean by “did not survive”? Disease prone? No cold tolerance? Or just not worthwhile?

Joel, I would guess that they were missing some genes required to grow to the next step (continue growing) - by the end of the first summer, most were dead. I did not do any deliberate culling.

From what I remember when I raised geraniums from seedlings, the albinos would grow then all of a sudden droop then deydrate into a puddle of nothingness.

Just out of curiosity, do the yellow cotyledon seedlings tend to germinate first??

Liz

Liz, I’m not sure if your question was directed to me, but I’ll give the little answer I have - no, so far there does not seem to be any relationship between the albino characteristic and germination timing. But today I have 7 more seedlings, with the same percentage yellow!

If any of these albinos survive and turn into something useful, I’ll come back with that news. Thanks!

Thanks Joel, I had one albino seedling this year that came up 2-3 weeks before anything else from that cross. Subsequent seedlings have all been green. Good luck with those seedlings, Liz

Liz, I think they germinate similarly to normal green seedlings, but it would be interesting to see if there is a difference.

I have a couple right now that clearly have yellow cotyledons, but have true leaves that are green. This is usually not the case. The majority of these die. I will try to take a photo tomorrow.

Jim Sproul

Here’s the photo that I took of a mini seedling. You can see that it is recovering and should do okay. Interestingly, this group has a yellow pollen parent that I have seen a larger number of albino types with other seed parents when the same yellow pollen parent is used.

Jim Sproul

Interesting. From what I remember of my gerniums that had a lot of albinos, a certain variety dominated the albinos. It was Pelargonium ‘Orbit Scarlet’. I remember because the true red color was a good seller at the spring sales…

Hmmm, cool seedling Jim.

This reminds me of a class of mutants in maize called virescents. In the spring under cool temperatures the seedlings are albino, but when it warms up, assuming that the seedlings are still alive, the leaf tissue turns green.

I was curious about the timing of germinating albinos, because some of the albino mutants in maize are carotenoid mutants and this is the pathway that leads to ABA, the hormone responsible for dormancy.

Liz

I’ve never seen an albino that forms chlorophyll after it begins growth. Any I’ve had inthe past of this type typically linger for a time then expire.

Robert, I have rarely seen albinos produce true leaves with chlorophyll, but in this batch of about 35 seedlings there are three!

Liz, I wonder if there is a connection with the pollen parent of these being a yellow rose. If I recall correctly, carotenoids are also involved in the yellow pigment in roses, right? It seems that yellow roses in particular have more of a delay in germination than the other colors???

Jim Sproul

Jim, yes the yellow color in roses is due to carotenoids. Your observation about yellows having a delayed germination is interesting. I guess it is consistent with my very limited crossing experience. From my notes gleaned from the old literature on inheritance of rose characteristics, there may actually be 2 different mechanisms behind yellow roses - yellow (yyyy) being recessive to “almost white” (YYYY). This particular type seems to be associated with cleavage of the carotenoids resulting in fragrance in the “almost white” class, and non-fading dark yellows. The other mode - white (w) is recessive to yellow (W—). The white type seems to be associated with lack of carotenoid synthesis in the petals. In corn at least there can be a fair amount of tissue specificity and redundancy with some of the genes, such that an endosperm carotenoid mutant does not affect the biochemical pathway in the embryo or in the vegetative tissues. This is not always the case, and I suspect that the same is probably true in roses.

Liz