Complex sentence: Citron in general is believed to be a very pure ancestral species, it is usually fertilized by self-pollination, and is therefore generally a male parent of any citrus hybrid rather than a female one.
Split into simpler sentences: Citron in general is believed to be a very pure ancestral species. It is usually fertilized by self-pollination, and is therefore generally a male parent of any citrus hybrid, rather than a female one.