"Andrew" wrote in message ...
In the case of a hybrid
like Susan (falcatus x wenthalii) there is little doubt that both
parents contain anthocyanin (how else does falcatus get the red
striping on the labellum) and, given that most other Sarcs contain
anthocyanin, what is it about weinthalii that makes the wenthalii/
falcatus anthocyanin:co-pigment ratio perfect for producing blue tones
that are unable to be replicated in any other falcatus hybrid?

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Good question. I've been googling like mad looking up Sarco species. There doesn't seem to be much on anything in weinthalii that would lead to blues, does there? I suspect you are right about the co-pigment pathways, genes turning on and off at the right time, ect. I have a feeling Morris may be correct in that a breeder would need to know the individual clone that'll have the proper pathway that leads to blues.

Ha! You inspired me to look it up: Griesbach's article on Custom Colored flowers he states "One of the major reasons why flowers containing the same anthocyanin can be different colors is pH (Stewart et al., 1975). As the pH becomes more alkaline, the color of a specific anthocyanin/co-pigment complex becomes more blue. All the anthocyanins except pelargonidin have the capability of producing blue flowers (Asen, 1976)." (But I suspect you knew that already.) He also points out several other hybrids (like roses etc) that have managed to increase cellular pH in vivo, and so become more blue....so I suppose that pH change is what weinthalii brings to the table. (??) But what do I know....

This stuff always amazes me, but I suppose I shouldn't be so naive. Breeders look for these traits and encourage them. That it happens so quickly in terms of bench time (ie time from flask to flower) and # of generations. especially in these species that often are difficult to grow or thrive, well, I'm always impressed.

Thanks for making me get up off my butt and do some research.

K Barrett