Pubescence in peach fruit is controlled by the Gg locus, with the homozygous recessive being the glabrous-skinned nectarine. The roughskin character in peach causes the loss of all long hairs on the epidermis of the fruit. Under a microscope short stubs are visible. The fruit is rough to the touch and appears dull rather than shiny as a nectarine would appear. A pleiotropic effect is lack of hairs on the dormant leaf and flower buds, making them noticeably shiny to the naked eye, unlike normal peaches and nectarines. The roughskin character appeared in 3 of 70 seedlings from the cross of Pekin × Durbin. The remaining seedlings all produced normal peaches. Sibling F2 progenies segregated for peach and nectarine, and in one case, for roughskin as well, indicating the cross was valid. Results from numerous crosses and F2 populations indicate this character is controlled by a single recessive gene, which is hereby designated rs. Nectarines homozygous for this gene have glabrous buds, but otherwise appear normal. The origin of the mutation is unclear. Selfed seedlings of Pekin and Durbin have not expressed the recessive form of the gene. Possibly a limb of the Pekin tree (now gone) used for the crosses had mutated to the recessive form at one or both loci. The homozygous roughskin progeny would have then been inadvertent self-pollinations rather than hybrids, since none of them segregated for nectarine.
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