Characterization of tree architecture in two-year-old apple seedling populations of different progenies with a common columnar gene parent

Main axis and branch growth characteristics were measured during and after the first two growing seasons of 209 two-year-old 'Telamon' x 'Braeburn', 'Telamon' x 'Sunrise' and 'Telamon' x '110' apple seedlings. Each parent cultivar exhibits a different tree architecture: 'Telamon': columnar, 'Braeburn': Type III, 'Sunrise': slender, type II, '110': columnar. Variables describing the number, length and position of the branches were used to separate four different architectural groups within the 209 seedlings. A continuum from trees with few and short shoots to trees with many long shoots is observed. Consequently, apical dominance and apical control appear positively correlated. As the branching habit of one-year-old 'Telamon' x 'Braeburn' seedlings was poorly associated with architecture after two years, it was not possible to predict tree architecture based on the branching pattern of one-year-old seedlings.