Piper nigrum is a member of a clade of Sri Lankan endemics and did not originate via hybridization between the previously suggested parental species, P. galeatum and P. trichostachyon. Autotetraploid varieties of Piper nigrum are predominant in cultivation, probably due to their increased vigor and higher yields, although diploid varieties are also present, demonstrating that genome duplication probably occurred recently in cultivation.
Metschina et al. (Thu,) studied this question.