Oncidium x Tolumnia breeding adventures
 

In another thread, I mentioned that I wanted to create some crosses that would incorporate Tolumnia and Oncidium—after some digging, I found out that my efforts may be in vain! In my other post, I included a quote that I’d like to share again:

“Tolumnia intergeneric breeding was best summed up by W. W. G. Moir:

‘But nowhere in orchid breeding is there as much wasted effort as in trying to cross the species and hybrids of the Variegata[Tolumnia] into other Oncidium or intergenerics of the Oncidiinae. If they do cross, they lose their Variegata identity entirely since they are completely dominated by the characteristics of the other plant.’

One might say that Rodrumnia is the exception, but I would counter that it took 35 years and four generations of breeding with Tolumnia to obtain a hybrid that was widely used. With Rodriguezia five to six generations removed, it is almost safe to say that these are Tolumnia hybrids.”

That was an excerpt from a document amongst others dated 2022 created by Karl Varian that were made available through the Greater North Texas Orchid Society.

Despite taking their wisdom into account, I made the crosses anyway and wanted to share some of my preliminary results…

Tolumnia Jairak Firm ‘Pink Lady’
https://i.postimg.cc/fVG7Skwz/IMG-2132.jpg
Oncidium Sharry Baby ‘Red Fantasy’
https://i.postimg.cc/G9McgBgq/IMG-2125.jpg

I had attempted this cross both ways—Tolumnia pollinia onto the Oncidium and Oncidium pollinia onto the Tolumnia. That was on 1/22/25 and the next day on the Oncidium, I had noticed the stigmatic surface I pollinated(inside the column or the dancing lady’s ‘head’), which was cupped in shape, had begun to almost swell outwards! As of today, the pollinated Tolumnia flowers have yet to show any discernible differences like the pollinated Oncidium flowers initially had, but the Oncidium flowers had another surprise—the tiny petal-like flares/structures that border on the left and right of the column had folded themselves over, covering up that stigmatic surface completely!

The dancing lady has veiled her face—compare this to the unpollinated flower above
https://i.postimg.cc/Xrq2wksc/IMG-2129.jpg

I know these signs aren’t indicative of success—I don’t know if the capsules will develop, and even if they do make it to harvest, the resulting seed might not be any good. At the end of the day, I’m just trying to have fun and I’ve succeeded in that so far!

I’ll post updates of the progress, both positive and negative, as they come up—stay tuned!

Wow! Interesting observation! I bet the folding can squash the pollinia into the stigmatic surface and enhance the contact. Amazing!

Thanks for sharing!

I rather like that feature on the Onc. Sharry Baby flowers—I made another cross using a different Tolumnia onto an intergeneric Oncidium and will see if they too will cover their faces(how modest)! The Tolumnias, on the other hand, let pollination get to their ‘heads’—the lady’s ‘head’ on the Tolumnias is swelling with…pride? Will post pictures comparing pollinated vs unpollinated Tolumnia in a bit!

Here is a comparison of the Tolumnia flowers…Note the swelling of the ‘head’

Not pollinated
https://i.postimg.cc/MMq17YHf/IMG-2135.jpg
Pollinated
https://i.postimg.cc/LYs4zqt3/IMG-2141.jpg

The expansion of the column indicates that the viscidium has been "violated", but that does not indicate that pollination has been successful.

When the individual pollen grains germinate, they grow pollen tubes down into the ovary (the short bit of "stem" that connects the blossom to the stalk) in an attempt to "consummate" the pollination process, and at that point the ovary will swell.

That, however, does not mean the cross has "taken", either. Pollen tubes that are too short and genetic incompatibilites are common reasons for failure.

It can be quite frustrating, as I've seen full-term, fully-developed capsules containing no viable seed.

I certainly did some violating…Especially to the Tolumnias because they’re mounted in a position that makes pollinating difficult!

Also, thank you for sharing the info about the pollen germination and tube formation, Ray—I’m kind of embarrassed to admit that I had no idea how pollen worked at all!

I’ve seen people viewing seed under magnification looking for embryos—assuming I can even make it to that point, I might need to consult some microscopy aficionados! I actually made more crosses than I’d need so that if capsules develop, I’d have some that I could spare for analysis under a microscope:biggrin:

Thanks again, Ray—I really appreciate any elucidation on the topic!

Dont you just love conversations that theres no way to be a part of. Overwheming, I love it.
Oh yea, we would love to see pictures under that microscope if possible. I know that takes special instruments.

:rofl: I'm totally with you. Fascinated but waaay out of my depth!

You’re both apart of the conversation by bearing witness to it, WD and FranningtonBear! You’d be surprised what people can accomplish with a bit a resourcefulness and the right guidance—there’s a scene of folks that are pulling off genetic modification of bacteria in impromptu labs!