I hear a lot of talk about crossing related species. But it would be great to have a resource to consult about what can cross and what you may not want to cross.
Things like:
Broccoli, cauliflower, cabbage and kale can cross.
What you may not want to cross:
You may not want to cross sweet and hot peppers, if you want to retain the sweet or hot in future generations
You may not want to cross sweet, dent and popcorn
@VeggieSavage is very interested in plant taxonomy and has done a lot of work classifying some garden plants…
I would say, crossability at best is complicated. You can have 2 different pairs that cross between species, but one has very high rate of success and the other has very/fairly low rate of success in terms of seeds that are formed. In either case you get almost certainly some crosses. Cross might work only one way, but works easily that way. Might work both ways, but the other way F1 has infertile pollen and you may or may not be able to use that to make backcrosses and that way get viability back. Etc.
Examples you are giving are mostly within same species. Only with sweet and hot peppers you can have hot peppers that aren’t in the same species as sweet pepper which is c.annuum. Most common hot peppers are also c.annuum so they cross freely. Other species of hot peppers have variable crossability with c.annuum. So what you should first look is that are what you are growing same species. If they are same species, they will cross, barring that their flowering is at different times or like with corn, there is dominance order within the sweetness allele that makes crosses possible only one way unless the dominant form doesn’t have it’s own pollen available. Mostly within same species it is certain that they will cross. With related species it’s rare that the crosses happen completely freely. More common is that there is a change of a cross, but you would not expect it to happen unless you made forced cross.
Then there is also how easily those species cross pollinate. Like with cucurbits changes are very high that any fruit has been pollinated with flower from another plant. With peppers the rate is already considerably lower and most likely to happen between plants that are next to each other. Even little bit of distance will make cross pollination highly unlikely. That coupled with that you are growing a hot pepper that is different species than sweet peppers and it would be like winning in a lottery to have a unwanted cross.
I’ve studied this exact question for majority of crops. Phylogenetic Trees paired with understanding the hybridization barriers is all you need to know to see if crops species are cross compatible.
I am the Phylogenetic Tree Plug, I gotchu on pretty much any Phylogenetic Tree you need for any Crop Species (Phylogenetic trees are basically the family tree of any crop species, it shows you which species are closely related & thus more likely cross-comptaible). Tell me what crop species tree you need here : I'm the Phylogenic Tree Plug, What do you need?
I can also tell you what is likely & not-likely cross-compatible. Ask away!
It’s also important to note that wide hybrids are possible, especially with outside the box methods such as
These 2 methods (I learned from Russian Plant Breeder Ivan Michurin) when combined can bypass a lot of hybridization barriers, Mentor Pollination works especially well with Interspecies Squash (Cucurbita spp.) Hybrids. Mentor grafting has been tested on Eggplants & successfully can transfer purple fruit color into white fruited plants.
It’s also important how any plant family/genus evolved it’s hybridization barriers, some plant families often make inter-generic hybrids & others have strong hybridization barriers even within the same family.
There is a trend where plant families that evolved through Polyploidization events (Chromosome doubling) often bypass mis-matching chromosome numbers hybridization barriers. Good examples of this are
Good examples of plant familiy/genus where mis-matching chromosome numbers are a real hybridization barrier are
I have tried the mentor pollinisation and it seem surprising. I have mixes the pollen of two moschata varietys in the piltil of a maxima flower,the fruit was get fat, unfortunately the alone viable seed don’t have germinate.
When you seeing that the most part of the seeds seem flat you understand that something happenend.
For improve my pollinisation the next time put avorted pollen of maxima with two differents fertiles pollens of moschata can helped to success my crossbreeding?
Seed to Seed by Suzanne Ashworth was where I got my first exposure to the botanical classification of vegetables. Im talking about basic stuff like cucurbita species. But this was years ago, maybe there are better ressources now.
Hmm… did you also mix in any maxima pollen to pollinate the maxima ovary? Or just strictly 2 moschata varieties without any maxima pollen?
For cucurbita especially, you need both species pollen to bypass hybridization barriers. The following generation may still have F1 sterility issues for which you need to mix both parent species pollens again.