I read about cherries, and each cultivar is associated to a mark like S1S4, S3S6 - or similar.
I understand this is something related to genes, but could not find a comprehensive explanation on this topic.
I though do find explanations like this:
The fertility in sweet cherry is determined by a gametophytic self-incompatibility system, controlled by a multi-allelic S-locus who prevents self-pollination.
However, I have the hardest time figuring out the meaning of such sentences. :(
What do those marks mean? What is the practical value of that information to gardeners? How do I explain them to my neighbor? (I certainly would not like to tell him: "Your cherry's multi-allelic S-locus controls its gametophytic system".)