yep

froggy

Though viral infections can cause varieagation it is uncommon for plants to survive long (in the wild) with these infections, since chlorophyll production is affected. The most common form of variegation is chimeral and can be evidenced by either yellowing or whiteness of stems and or foliage (sometimes blossoms) as is also the case with pathological variegations.

Al

My understanding, though maybe an oversimplification, is that virus-caused variegation usually appears as irregular patches or mottling, different on every leaf -- whereas chimeral variegation shows rather more regular patterns or at least banding or edging of leaves. A good example of virus might be Abutilon 'Cannington Carol', of chimera maybe Sansevieria trifasciata 'Laurentii', and Euonymus fortunei cultivars. Since these last include both yellow and white-variegated cultivars of almost identical pattern, I would not have thought that these colors are of different origin. And the mottled Abutilon cultivars include some quite dark yellows.

Can someone more knowledgeable about this subject say whether I am on the right track?

I think you hit the nail on the head Tony. Viral variegation can occur anywhere in the leaf with no particular pattern to it. As this is a disease it can be transported to any cell. The result is splotches of yellow/white colour. Examples are those tulips infected with TMV or Abutilon.
Chimeras on the other hand have a pattern to their variegation. As the mutation occurs at the meristem level, the ariegation occurs at definite points : it could be inner or outer, etc.
I do not agree with the statement that white occurs in only virused plants. White just shows that there is no Chl. that's all it says. The lack of Chl can be a result of a mutation or a viral infection.

Thank you for your replies!

Is there a way to introduce a virus that would make a plant varigated?
......cheryl

Thanks everyone for input on this very interesting topic. I live in Japan. People are obsessed with anything showing variegation, so just about any plant can be seen in a variegated form. Clivia, raphis palms, a form of St. Augustine grass (grown as a pot plant) and many orchids are examples of plants developed here showing all mannar of variegation.

I was amazed when I went to an orchid show the first time. A whole section of the show (in Fukuoka City) was devoted to native orchids and many of these were variegated. The amount of variation created within even one species was incredible to me, for example, Dendrobium moniliforme. Literally hundreds of cultivars have been developed (not all variegated) of this species.

So, my question is, "How do they do that?" Certainly this isn't just a matter of selective breeding. Could anyone point me to a source of information on techniques used to create these plants, it is fascinating to me. Here are a few shots of some orchids I've acquired: a Neofinetia falcata, Cymbidium ensifolium, and two different Dendrobium moniliforme.

Here is a link that might be useful: {{gwi:432945}}

Plantfreak, your orchids are lovely. You and others may be interested in "Variegated Plants in Color" by Yoshimichi Hirose and Masato Yokoi with more thn 1400 photos with both English and Japanese text. It's marvelous...covers trees to succulents from all over world. Even better, has good info on cultivation and propagation.This is the only book I have seen specifically on variegated plants except for a book by Susan Condor which is nice but doesn't have nearly the scope.

josh

Here's the URL to a site that describes chimeral plants and how it is done.

Here is a link that might be useful: Chimeras

Josh, thanks for the lead on the book. Nazanine, thank you for that detailed report on Chimeras. I suspect that I will get more of these plants the longer I stay here. PF

May be a late posting, but here is a new book on variegation. Asiatica Nursery is selling it. Here is the description of the book:
A brand new variegated plant book from Thailand, by Dr. Neong Phanit and Mr. "Jiew" Promote Rojruangsang, featuring variegated subtropical and tropical plants grown in Thailand. Many of the plants included have never been seen outside Thailand. The text is in Thai, but there are about 400 exceptional color photos with Latin names. Hardcover, 200 pages, published by Amarin Printing and Publishing. This book is a must for every variegated plant hobbyist and anyone who enjoys beautiful foliage.
Enjoy, Natureboy77

Here is a link I found talking about variegation in Orchids. Hope it sheds some light for you interested.,,,,,Debbie

Here is a link that might be useful: Orchid Improvement through Mutation Induction by Gamma Rays

Tony and Nazanine, I think you have placed too much emphasis on the organization of the variegation as an indication of chimerism. Variegates with regular edges or medio-variegation are certainly the most stable and the most conducive to tissue culture and thusly the most attractive to commerce, however, they are not the only ones. Mericlinal mutations can effect a small portion of a single leaf, thus looking quite irregular. Periclinal chimerism effects less than an entire plant as well.

Take a look in the weed gallery. I recently posted two photos of a variegated Red Clover. The #1 photo in particular might come across as rather random to some but I hope you will agree that it is true variegation. Keep in mind it comes from the same plant as the #2 photo which shows the plant trying to organize into a (severly) edged form. However, I have seen many variegates that display the first type of variegation but not yet the second. Furthermore, many are much less dramatic thusly making much less exciting photo candidates
That being said, I will agree that virally caused variagation has a "splotchy" look whereas chimeral variegation, if not organized, is at least more streaky. But we must be careful as "splotchy" and "streaky" take on different meanings in the minds eye of different beholders.

And, additionally, there is such a thing as DNA based variegation that has a different look than chimeral variegates- a fine speckling of lighter pigments.