ASHS 2024 Conference

The Maryland Tree Architecture Project (MD-TAP) used classical plant breeding methods to create, identify, select and then patent grower-friendly apple trees. The project began in 1991 with the open pollination of 'McIntosh Wijcik' trees set in an isolated 'Gala' block. Elite seedlings resulting from that initial cross then served as male parents in an open-pollination of commercial cultivars well-adapted to the warm, wet, windy, Mid-Atlantic climate. Two scion-dwarfed, apple trees producing good quality fruit and demonstrating a reduced susceptibility to fire blight resulted from this effort. These two selections were patented as 'MD-TAP1' and 'MD-TAP2' in 2023. A replicated field trial was set in 2016 to compare these two scion-dwarfed selections, with their wild-type siblings also from this program. Trees were budded onto 'M.111,' a semi-dwarfing rootstock to assess their growth habit and tree size without the benefit of trellis support or sustained annual pruning. Trees were set at a 2.75 by 4.25 m (9 by 14 ft) spacing and are still manageable. Despite annual pruning, they are similar in height to trees in an adjacent tall-spindle planting budded onto dwarfing rootstocks. The University of Maryland concluded two Materials Transfer Agreements (MTAs) with other universities before the patents were allowed. After patenting, the University began contacting commercial nurseries in the Mid-Atlantic Region for future testing and licensing.