- Cross plants to make a hybrid
- Grow the F1 plant from the seed
- Use fancy techniques to grow a plant from pollen alone
- More fancy footwork - now your seed is stable, do with it as you please.
Result: a stable cross within just two generations (rather than the 6,7,8) and arguably a more targeted approach bringing your wildest crosses to fruition.
Despite this is only my first year growing, I've been swept away by the beauty and diversity of the Capsicum genus and I've spent these past several months intensely researching some of the more technical details of the genetics of these plants. I'm so enthralled and can't wait to develop some crosses of my own. Though I don't have a background in botany or horticulture, I do in biomedical science, and so I've had a bit of a leg up in starting to get my head around things.
While I plan to cross by hand, admittedly there's a lot in the way of producing a new, stable cultivar. Following the initial dihybrid cross (selfing of the F1), there's a lot of variation in the F2. Say you're interested in 3 gene loci (Aa, Bb, Cc), then it follows that only 1/64 of your F2 will actually be homozygous recessive at the 3 loci (aa, bb, cc). In order to get your desired cross, you have to grow out a lot of seed, and to stabilise you need to repeat the process for a few generations, tolerating some subtle and not so subtle variation (obviously not for the fully recessive plant...but anyway) Don't get me wrong, there are probably a lot of happy accidents that come from this process, but surely there's a more targeted way of getting your desired cross (cue anther culture)
Doubled Haploids/Anther culture...
So I've been reading up on a technique used commercially, which involves the usual cross between the two parents, and growing out of the F1 seeds, but following this, the anthers are taken and cultured in such a way that what you get are immediately stable (homozygous) without any further crossing. To explain this genetically, take the AA;BB;CC x aa;bb;cc cross. Your F1 is just Aa;Bb;Cc and then there are 8 different F2 genotypes as a result of random assortment. So your pollen might have the following A;B;C / a;B;C / A; b; c / and so on. What the technique involves is then taking the pollen (or anthers) from your F1s and culturing them in such a what that you actually get a plant that germinates from this culture without having gone through sexual reproduction. The resultant plant is a hemizygote, or haploid, that has only 1 set of genes, instead of the usual 2 sets. With a chemical such as colchicine you can then initiate doubling of the genome into 2 sets (or more...) Ultimately, you get a plant that bares fruits with seeds that are all homozygous, depending on the genotype of the pollen (i.e. A;B;c becomes AA; BB; cc or a;B;C becomes aa;BB;CC, etc)
Now for my question ... has anyone got experience with Anther culture or related techniques and has actually ever tried this at home? If so, what protocol did you follow?
Though there are some specialised chemicals/materials involved, a cursory search has found that they are both not excessively costly or illegal to possess.
If anyone is interested in the protocols I've come across I can include some references!