Analysis of the ‘A72’ Peach Tree Growth Habit and Its Inheritance in Progeny Obtained from Crosses of ‘A72’ with Columnar Peach Trees

Abstract

Since the first report of the ‘A72’ semidwarf peach [Prunus persica (L.) Batsch] tree in 1975, no new information has become available on this genotype. We evaluated the growth habit and verified the inheritance of ‘A72’ in a population of 220 progeny derived from self-pollination. Detailed tree and branch measurements revealed a unique forked-branch (FBR) character of the ‘A72’ (Nn) phenotype. The progeny segregated into 1 NN:2 Nn:1 nn. NN trees were indistinguishable from standard peach trees, Nn were FBR, and nn were dwarf. Hybrids between ‘A72’ and columnar (brbr) peach trees confirmed that FBR is inherited as a monogenic trait that appears to express incomplete dominance. ‘A72’ (Nn) trees were later blooming than sibling NN trees. The relationship (linkage or pleiotropy) between the growth habit of ‘A72’ and late bloom is not known. The structure of ‘A72’ trees presents new opportunities to breeder/geneticists, physiologists, and horticulturists to further explore the plasticity of peach tree growth and architecture that can be achieved through breeding. Applications of the ‘A72’ growth habit for commercial fruit production and as an ornamental, particularly in the dwarf form (nn) and in combination with the columnar tree (brbr) form, present opportunities that await exploration.