A peach is a peach is a peach. Or is it a nectarine? A common question the public asks peach breeders and  producers is: What is the difference between a peach and a nectarine? The prevalence of this question illustrates the importance of pubescence and the selection for or against “fuzz” in commercial breeding programs. Simply put, a nectarine is a fuzz-free peach.

The presence or absence of skin fuzz is controlled by a single dominant allele associated with the G locus."The nectarine-type allele is recessive to the peach-type. Hidden within many peach cultivars is the genetic potential to produce nectarine offspring—because those cultivars are heterozygous.  Although other attributes, such as “nectarine flavor”, are found in nectarine cultivar descriptions, this may be due to other loci, not pleiotropy at the G locus, as breeders are able to develop peach cultivars with the “nectarine flavor”. To predict if an individual will be a nectarine or a peach and if a peach has the genetic potential to produce nectarine offspring, the indelG DNA test was developed.* The indelG DNA test has two alleles: “P”, the presence of which always results in a peach, and “n”, which must be homozygous to result in a nectarine. Both alleles are common in U.S. breeding germplasm.