I am looking for answers to the question above. Both inside and between the species. Where would you put the crossing rates in your experience?
The most commonly grown species of Capsicum to my knowledge are:
hi Malte,
on the theory I had this document :
on the practice I grow in the same place :
a sweet pepper population C. annuum
a population of chili peppers C.baccatum
and I never had a cross !
That still seems to align with your schema. If they happen to hybridize, you would suspect the seed to germinate normally (NG). What you’re telling me is that the crossing rate seems to be very low, right?
I’ve been growing annums and baccatum together with the same idea in mind. I only keep seed from the solo baccatum and of the annums only jalapenos which I wouldn’t mind seeing a cross in. It’s only been 2 seasons to grow out the seed but I haven’t had any crosses and I grow lots of plants closely together, at least 50+ per variety.
This year I did pull 5 baccatum plants that didn’t have any fruit when everything else was fruiting and I wondered if they were not fertile. Either way they had to go. The way I’m growing sacrificing a few is no problem.
I am really pushing the season so I usually only take seeds from what are the very first fruits. In another thread someone noted that early in the season the pollinators aren’t out as much and there is less crossing. That might be a factor in my lack of crosses too and could be a strategy for planting/fruit seed selection. I thought I might experiment next year to see if I mark a few fruit during peak pollinator mayhem to see if they do show more crosses in species. We’ll see!
Not sure what your goal is but peppers are self fertile so isolating a flower to keep crosses out is very straightforward/low effort.
The tough part seems to always be that the different species flower at different times and it seems they all really are only going at the same time here at this flex season right before winter comes so I’m stuck with overwintering or indoor growing peppers that I cross at the end of the season. The capsicum Capsicum flexuosum was seen as a bridge to cross the more wild type with modern chinense and annum. But they are generally more difficult to grow and obtain that I have focused more on the annums Jalapeño and Poblano, as I eat them the most. I have not worried about trying to cross them with the chinense or flexuosum after a couple generations of Jalapeño x Ghost pepper left me with the sort of worse of both and none of the benefits.
2 cents and no AI editor 
red = prolific crossing
orange = sporadic crossing
white = sterile crossing
yes I cultivate:
a landrace finished chilli C.baccatum Aji Colorado Alpino
a grex sweet pepper C.annuum
According to this document the crossing rates should be high in all mixed cultivated annuum. I haven’t found a single hybrid in 3 years !
So still according to the literature I could have a probable crossing between C annum x baccatum, but by distancing them of some meters I reduce the probability near zero.
If you want crosses in peppers, I would do it manually. If you have staple varieties I would also mark the crosses. With F1s and unstaple crosses I have thought it’s enough to just make random pollination (within species). Although I have only used the earlier flowers that have the best change to make viable seedes in my climate. I’m sure pollinators will do a decent amount off crossing, but in my short season they tend to notice pepper flowers a little too late and possible crossing happens on those late fruits that I generally don’t save seeds from. Also some of the bigger sweet peppers might not make as many flowers and are thus less interesting to pollinators. Baccatums did seem quite interesting on the other hand. Whether it’s the amount of the flowers, I don’t know. Maybe the typical baccatum flower colour is more visible to pollinators? Atleast eggplants seem to be a lot more interesting to pollinators and I have observed some crosses even though I have grown them a lot less. The flowers themselves aren’t any better for crossing. And the only certain cross in peppers was with purple flowered variety. Maybe it was only easier to see which brings us to the main problem with peppers; the changes are that you are able to pick out only portion of the natural crosses. Unless you have a lot of space, hoping for natural crosses at the start of the project will probably lower the genetic variability before you get to F2+.
I have stupid amounts of F2+ pepper seeds, both annuum and baccatum, but likely not crosses between the 2 species. If you want some, I could send you over the winter once I get them cleaned up.
I’m actually quite happy about crosses just within the species. I’m mostly curious how often for example different varieties of annuum cross with each other. If they’re relatively outbreeding, they’ll be easier to locally adapt. I just can’t seem to find a clear answer on the crossing rate within the species. Do you know or have a qualified guess?
If your seed came from Capsicum grown outside (not greenhouse) with relatively little watering, that would fit my growing situation really well.
Good resrouce!
@mbcoll Fantasic Phylogenic Trees!
From all my Capsicum research I’ve done, they break down into 2 subgenus type groups that don’t cross, the white pepper seeds all cross with white pepper seeds, the black pepper seeds only cross with black pepper seeds, there is no White Pepper seed x Black Pepper seed that I know of.
Capsicum annum x Capsicum baccantum is fully possible if you do Mentor Pollination & Mentor Grafting. Simply Extract a mix of C. annum pollen & C. baccantum pollen, mix the 2 pollens up and apply to both C. annum & C. baccantum flowers. This tricks the plant to accept foreign pollen along with it’s own species pollen as to not loose it’s own pollen. Introgress the next generation by repeating the mixing pollens with the new hybrid & the parents that made it (Especially a Huge Hybrid swarm of Hybrids & parents species). Eventually you’ll smooth out all hybridization barriers. In a nutshell you are creating a Bridge species to help smooth out Hybridizations.
Also Mentor Grafting can help bypass some hybridization barriers too. For example if you a Young Hybrid Pepper plant, graft it on the plant you want it to resemble & it will take on those traits via Horizontal gene flow as the mentor plant pumps water & nutrients to the hybrid scion. Also of you swap scions on the 2 species you want to cross, the other species pollen will be less foreign to them.
You may also find this Phylogenic Tree useful
@malterod All same species cultivars cross readily. Since Peppers are technically a Perennial non-frost hardy shrub that we grow as annuals, you can Graft multiple varieties onto 1 pepper plant & virtually guarantee crosses (The 27 Plum/Peach/Prunus tree is a good example). Without grafting, Pollinators will cross them for you but grafting is closer than any spacing thus more different variety flowers are closer to each other.
@mbcoll Do you have a Higher quality Image source of the Phylogenic Tree? I’m trying to read the Phylogenic Tree on the left. Which video did you screenshot this from?
No just the screenshot that I posted.
Looks to be from 2021 that will require a YouTube history deep dive as I didn’t take a vertical screenshot with the video title. Facepalm
Fantastic! Thank you! Did you happen to also find the Phylogenic Tree? I found some others and was wonder if they had similar arrangements.
What I found in Particually interesting was the Phylogenic Tree that has ID Traits, specifcally the heat Trait. Seems that the other wild species are completely heatless & edible like a Berry, like Capsicum regale & Capsicum rhomboideum for example. I don’t think they are crossable because they are so Photogenically distant, way past even the Black Pepper seed group. Is it fair to Consider it a Separate genera or subgenera?
Didn’t look for it or find it in my YouTube history yet
Joseph had put an estimation to 10% which I don’t think is far off once you get to later stage fruits that were formed during full bloom. This is enough to keep the population evolving, at least as long as enough selection pressure is applied.
Like I said, I would still start with the crosses as you might make too much selection before you get to F2+. Also better observe if natural pollination happens. It’s always possible that just that spot doesn’t have the numbers to make natural crossing prevalent. Flowers themselves are good for crosspollination, but also easily self. Right now I’m not making ( too much) selection based on flower types, but in the future I’ll try to elimate flowers that have really short stigmas.
a stupid question I can’t get an answer to.
If I cross 2 capsicum (varieties and/or species), the resulting fruit has seeds. But all these seeds have the same genome? or each seed is different?
If they are two staple varieties, then yes. Wild species I would expect there to be enough variance for F1s not to be genetically identical, but from the outside you might not see the difference. Same applies to varieties that aren’t fully staple, for example if they are from old landrace. Unless it has gone through really tight bottleneck at some stage, there is probably enough crosspollination to have some variance. In other species like in cucurbitaceae it’s probable that all varieties have at least little variance. Still F2 are were the fun really starts.
So it is better to make a lot of crossing and sow than a few seeds of each fruit from crossing? No interest in sowing 200 seeds of the same fruit to seek more diversity?
Yes, as many crosses with as many different parents as possible. It’s a little like pokemon-go, but just collect all the genes. There aren’t that many different genes between varieties and even one plant should make seeds with all possible genes within that cross. There are lot’s more compinations of the genes for sure, but you are not going to be able to grow them all anyway. You can grow just as many compinations of genes even if you collect little more variance using many crosses.
You could have the same varieties used on different cross pairs as you might loose some genes in one F1 cross, but not in the other. Maybe not something you need to worry about. With wilds I would try to make several distinct crosses (with same wild accesion parent) just for that reason. There are a lot more variance in wilds and you want to give all those genes the best change to make through.
