Plumgiant I Plum Tree Breeding for Giant Fruit and Shipping Durability

The patent applies preliminary action by pre-selecting parent trees with desired traits (self-unfruitfulness, fruit size, skin color, flesh color, clingstone characteristic) before hybridization. The inventor systematically crossed specific plum varieties (including 'August Yummy' and others) with selected parent trees, and pre-stratified seeds before germination. This preliminary selection and preparation reduced the time needed to develop the final variety by focusing breeding efforts on predetermined trait combinations.

The patent uses bees as intermediary agents to transfer pollen between isolated plum trees. Instead of manually transferring pollen (which would be complex and time-consuming), the inventor placed bees inside screen houses containing the isolated plum trees, allowing the bees to naturally collect and transfer pollen while maintaining the isolation required for controlled pollination. This intermediary approach simplified the pollination process while maintaining precision in fruit characteristic control.

The patent changes the rootstock parameter from own roots to grafted rootstock ('Nemaguard') to achieve both hardiness and adaptability. The inventor grafted the selected plum variety onto 'Nemaguard' rootstock, which provided the desired hardiness and adaptability characteristics while maintaining compatibility with the scion. This parameter change in the rootstock system allowed the tree to exhibit both desired properties simultaneously.

The patent produces fruit with composite characteristics combining giant size with enhanced durability traits. The hybridization process integrated genes for large fruit size with genes for firm flesh texture and thick skin, creating a composite fruit structure that maintains durability despite increased size. The resulting 'Plumgiant I' variety exhibits both giant dimensions and shipping durability through this genetic composite approach.