Floriani polenta corn - inbreeding questions

[gmuller]

I have a very limited gene pool of Floriani red polenta corn. I love the idea of establishing a decent population of this variety in Aust, but suspect it needs an injection of genetic diversity, since it has gone through two genetic bottlenecks since I acquired it.
My access to corn diversity here is quite limited, and my space is a bit limited as well.
I believe Floriani is a flint corn. Could I cross it to selected kernels from Glass Gem and still end up with a decent polenta corn?

If this seems like a possibility, I could grow a patch of floriani incorporating all the diversity i have, then plant a separate patch of Floriani with selected red kernels from Glass gem, detassel the floriani and fertilise with the glass gem to get F1, then next season back cross the F1 to the original Floriani, and select for relevant kernels.
I'm a newby at corn crossing and genetics.
GM

[Olaf Nurlif]

Depending on how hard it is to import seeds to Australia you could also try to get some lines from genebanks!
https://doi.org/10.7717/peerj.5123
In this article you can find among other things information about the origin of the beaked maize varieties in Italy along with some accession codes.

Assuming it's too complicated or expensive to import anything I think the approach with Glass Gem would also work.
The corneous endosperm of flint corns should be the same as the one in popcorns so in your population you would likely find anything from pure flinty endosperm to semi-flints and probably a few dentish kernels (if your Floriani Red Flint is similar to mine and has some dent in it).

There might be other challenges with Glass Gem as a parent tho - but I'm not familiar with the variety so I might be wrong here!
Floriani has an orange (to reddish) pericarp.
IIRC Glass Gem has white and yellow endosperm with many of the available aleurone (and pericarp?) colors available.

So in future generations you might have trouble selecting for yellow/orange color of the corneous endosperm if you get some white in there and it might be hard to get out all "unwanted" aleurone varieties.

I noticed as well that Floriani Red Flint is a bit inbred, the plants seemed a bit spindly and not too vigorous to me. I decided to use Cascade Ruby Gold as pollen donor and in the F2-population of that cross I got many very vigorous plants with huge cobs from that cross.
This year I crossed in Longfellow Flint into that population because I want to incorporate one trait from that but I might decide to go back to the "pure" Floriani Red Flint X Cascade Ruby Gold lines, not sure yet.

[Ocimum]

First a thing to consider: Some popcorns have a pollen incompatibility, and cannot be pollinated by other corns. I did not research for your variety.

... then plant a separate patch of Floriani with selected red kernels from Glass gem, detassel the floriani and fertilise with the glass gem to get F1, then next season back cross the F1 to the original Floriani, and select for relevant kernels.

I would do the opposite to you: plant one field of Floriani, plant a few rows of the other variety inside, and detassel the other variety. This allows you to keep more diversity within your field, as all the Floriani can be used as pollen donor.

Next year, you can again plant a few rows of the F1 within your field, detassel to get a BackCross (BC). And if you are still unsure if you want to merge your BC1 with your original population, you can separate them again till BC2 or BC3

When planting your lines of the other variety to cross (and the F1 as well): it may be necessary to have staggered sowing dates to be sure they flower at the same time. Otherwise you may end up with 2 varieties not flowering at the same time, loosing a year. This is especially the case in strange weather conditions.

[gmuller]

Thanks ocimum, the reverse strategy is a better idea.
GM

[Raymondo]

What did you end up doing with the Floriani? Did you cross it wth anything to broaden the genetic base?

[gmuller]

What did you end up doing with the Floriani? Did you cross it wth anything to broaden the genetic base?

Ray, I late-planted a few red kernels from some Aztec corns I had, but DTM was too long, and they didn't cross over in flowering time. Grant Cutler sent me some Floriani crosses he did, so i will incorporate them next year.

[Raymondo]

I'm after a good polenta corn and like you think Floriani on its own just doesn't cut it. I like the red-orange-yellow spectrum so I'll be planting a block of Floriani next to a block of Manning Pride (a local-ish yellow dent) next to a very small block of red and yellow flinty corn found in other collections. I may also run a line or two of Red Aztec along the side of the patch (detasselled).
If flowering times overlap I'll get some each way crosses where the blocks meet but still have some relatively pure Floriani and Manning Pride for later backcrossing.
If it were drier (will La Niña ever end?) I'd love to plant some flour corn too. I have some Papa's Red and Oaxacan Green that would be great to mix up. I may have to get my flour corn jollies vicariously though and give these to a friend who is very keen on flour corn!

[Jeremy Weiss]

I have no idea how you'd GET IT (between the rather stringent import regulations Australia has and the fact that even I haven't seen any for a decade or so) but Joe "The Seed Explorer" Simcox used to offer a red pericarped flint corn called Malagasy that he had found in Madagascar that might be a good candidate, as I imagine it is very well heat adapted.

[Raymondo]

Corn is indeed almost impossible to import into Australia for the small scale gardener. Only large companies can afford the very high import costs. Also, where I live, summers can be cool. The last few for example have seen temperatures no higher than 25°C (~77°F).

[Joseph Lofthouse]

Corn is indeed almost impossible to import into Australia for the small scale gardener. Only large companies can afford the very high import costs. Also, where I live, summers can be cool. The last few for example have seen temperatures no higher than 25°C (~77°F).

Last time I checked, it was legal to import corn into Australia, without restrictions, if it was grown in the state of Idaho. I'm only 20 miles from the Idaho border, so I've wondered if it would be lucrative to rent a field just across the border for a summer.

[Raymondo]

Last time I checked, it was legal to import corn into Australia, without restrictions, if it was grown in the state of Idaho...

That's true but you have to have a phytosanitary certificate verifying
1 Grown in Idaho
2 Treated with Carboxin and Thiram and
3 Free of maize dwarf mosaic potyvirus

All costs are borne by the importer. Too expensive for me.