Plum breeding

Abstract

A wild type of Prunus domestica (European plum) and especially the typical form of this species, the prune, is unknown. Crane and Lawrence (1934) suggest that the hexaploid P. domestica is a hybrid of P. cerasifera (cherry plum, diploid) and P. spinosa (sloe, autopolyploid tetraploid). The blue fruit colour is coming from the sloe; the other colours are originating from the cherry plum. Rybin (1936) found spontaneous intraspecific hybrids in the Caucasian region. One of this natural hybrids had 2n = 48 chromosomes and was morphologically indistinguishable from the common plum. He crossed P. spinosa and P. cerasifera, and obtained seedlings regarded as re-synthesised P. domestica. Most of these plants were sterile and had no or only some fruits. However, one hybrid was highly fertile; this supported Crane's assumption of the origin of P. domestica. A similar experiment was made by Endlich and Murawski (1962). The hybrid nature of P. domestica is nowadays widely accepted, and it is assumed that the species originated in the Caucasian region because P. cerasifera and P. domestica are native there.