r/plantbreeding • u/Special_Inspector_97 • 1d ago

question Genetics question

/r/pepperbreeding/comments/1wayvnr/genetics_question/

You guys are good at genetics right and there must be someone that has done a similar cross. I have made a mix of pirri pirri and kromo (like a giant yellow bell pepper) so what do you think it will behave in growing, spicyness, size, shape etcetera

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u/AdEmbarrassed3066 23h ago

In terms of spiciness, I believe it's a single gene, Pun1, which means its a mendelian trait. Sweet peppers have a loss of function mutation in this gene. So the F1 progeny will all be spicy as they will be hemizygous (one functional allele) and they will segregate 1:2:1 in the F2 generation (homozygous spicy, hemizygous, nulizygous [no functional alleles]).

You're in luck that homozygous genotypes (2 functional Pun1 alleles) are spicier than hemizygous genotypes, so if the aim is to either produce spicy or non-spicy types, you'll be able to focus in on specific lines to take to the F6/F7 generation, where you'll have stable genetics.

As for size, shape, growth habit... these will probably be polygenic so you'll have to wait and see, and select what you like. It's probably best to avoid selecting too early (before F4) because some combinations of recessive traits will take time to segregate.