Isozyme Phenotypes Support the Interspecific Hybrid Origin of Prunus XdasycarpaEhrh.

Abstract

The black or purple apricot, Prunus xdasycarpaEhrh., has been reported to be a naturally occurring interspecific hybrid between apricot ( Prunus armeniacaL.) and myrobalan plum ( P. cerasiferaEhrh.). The isozyme phenotypes of five black apricot clones support its hybrid origin since each one has at least two plum specific and two apricot specific alleles.

Prunus xdasycarpaEhrh., commonly known as the purple or black apricot, was first recorded in 1755 (8) and described in 1791. It belongs to the section Armeniaca(Miller) Koch (9). In the beginning of the twentieth century Schneider speculated that it was a natural hybrid between P. cerasiferaEhrh. and P. armeniacaL. (5). Evidence from several studies supports the proposed hybrid origin of P. xdasycarpa(3, 6, 7). This species is intermediate between P. cerasifera(myrobalan plum) and P. armeniacaboth morphologically (leaves, fruit, flowers) and physiologically (time of bloom, cold tolerance and tolerance to fungal diseases). Most clones of P. xdasycarpaare not highly fertile and produce abortive seeds with poor germination and have flowers with defective pollen as is observed in artificially produced plum x apricot hybrids. In addition, plants of the black apricot are only sporadically found where the distributions of apricot and the myrobalan plum overlap. The purpose of this study is to provide additional evidence of hybrid origin of P. xdasycarpavia isozymic analysis.