Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/12/2009
Publication Date: 2/8/2009
Publication URL: http://journal.ashspublications.org/cgi/reprint/134/2/236?maxtoshow=&hits=10&RESULTFORMAT=&fulltext=A72&searchid=1&FIRSTINDEX=0&sortspec=relevance&resourcetype=HWCIT
Citation: Hu, D., Scorza, R. 2009. Analysis of the 'A72' peach tree growth habit and its inheritance in progeny obtained from crosses of 'A72' with columnar peach trees. Journal of the American Society for Horticultural Science. 134(2):236-243. Interpretive Summary: New growth habits of peach trees can allow breeders to develop trees that are suitable for high density orchards that can be managed more efficiently, that can be mechanically pruned and harvested, and that will require less pesticides and fertilizers, making better use of available land suitable for fruit growing. Some new tree types may also be more suitable for home gardeners than the current large size peach trees. We have characterized a novel peach growth habit that produces smaller trees, blooms late to avoid spring frosts, and combines through breeding with other growth forms such as columnar to produce trees that may be useful for both the commercial and home orchard. This new information can be used by breeders to develop new useful peach varieties.
Technical Abstract: Since the first report of the 'A72' semi-dwarf peach tree (Nn) by Monet and Salesses (1975), little 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' phenotype. The progeny segregated into 1(NN): 2(Nn): 1(nn) based on this forked-branch character. Hybrids between 'A72' and columnar (brbr) peach trees confirmed that FBR is inherited as a monogenic trait expressing incomplete dominance. 'A72' (Nn) trees were later blooming than normal appearing (NN) sibling 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 form (brbr), present opportunities that await exploration.