Identical twins from one seed

When I first noticed this seedling, it appeared to have two identical buds on identical stems. Each stem had one cotyledon. While transplanting it, I checked whether the stems were separate all the way down to the roots, and found that there were two separate plants. So this appears to be a case of identical twin seedlings from one seed. The cross was Sonia X Olympiad.

[img]www.rosehybridizers.org/pics/2004.03.07sm.jpg’ alt=‘Identical twins’>

[img]www.rosehybridizers.org/pics/2004.03.12.jpg’ alt=‘Identical twins’>

Jim,

This is really exciting! You may well have haploid seedlings in your twins. They should be diploid if both parents are tatraploids, and as such would be a promising link to breed with rugosas and other diploids to overcome the sterility in seedlings from wide crosses with those types.

If they produce pollen I’m sure several of us would be interested in obtaining some to experiment with.

Congratulations, These twin roses usually die young.

Randy

Huh… I don’t understand how twins from a tetraploid cross should be diploid… Could you explain, please?

Hi Enrique,

I should have been more precice. In most cases of twins from one seed, one of them is haploid. It originates from a synergid which is a by product of meiosis that contains half the chromosome count and doesnt usually result in an embryo. Through some quirk the haploid tissue behaves as an embryo and grows into a seedling.

David? Where are you? I won’t be at all offended when you clear up some of my misconceptions. I certainly don’t understand the process well so I’m sure I have some of it wrong but I remember you writing about selecting haploids from twin seeds in one of our newsletters.

I’ve seen twins from citrus seeds quite alot but never had any desire to do anything with them other than seperate them from the stronger growing one.

Enrique, I wish I could be more help in explaining this but hopefully David will see this and reply.

Randy

I’ve seen twins from citrus seeds quite alot but never had any desire to do anything with them other than seperate them from the stronger growing one.

Somewhat off topic, but I would not compare rose seeds to citrus. I’m not a citrus expert, but I believe that the case of citrus is completely different. Citrus seeds(from what I’ve read) often have more than one embryo. One is a normal eggxpollen cross, the others are clones of the seed parent. Usually the clones outgrow the seedxpollen cross so that most often when growing citrus seeds you’re getting a clone of the seed parent (although the seedling must go through a juvenile stage (thorny, etc.) which a grafted citrus would not).

Chris Mauchline

SE PA, zone 6

It appears that haploids from twin seeds may not be as common as thought; see the link below.

Link: www.rosehybridizers.org/forum/message.php?topid=3190&rc=18&ui=164607472