Stone Fruit Propagation by Seed
Sexual propagation with seeds is only used to produce seedling rootstock, or in breeding new fruit varieties. Rootstock grown from seed is desirable because seedlings tend to have a deeper, more anchored root system than clonal rootstock (Hartmann, Kester, Davies, & Geneve, 2002), and have a lower probability of virus transmission from parent to progeny. Rootstock seed is inexpensive and generally has good germination percentages. Seeds used for propagation are generated in isolated planting blocks of rootstock cultivars. Netting planting blocks during flowering, and thus preventing cross pollination by animals, increases the probability that seed is a result of self fertilization or apomixis.
Sourcing seed from a nursery that has a similar climate as the location where the seed will be sown has shown to reduce any climatic adaptation, such as stunting, that might occur.
Seed is collected when the mature fruit is harvested, the fruit removed, seed cleaned and placed in a cool, dry place to prevent rotting or early germination. Seed from early maturing cultivars should not be used because the flesh matures before the embryo completes development. Embryo rescue, excision, and micro culture can be used to increase germination percentage of the early ripening varieties (Hartmann, Kester, Davies, & Geneve, 2002). Peach seed must be stratified to enable successful germination. Stratification is achieved by planting the seed at high densities (4 inch spacing) in a prepared, fumigated nursery row in late fall. Although seed chilling requirements vary among varieties seed will generally complete stratification in 3 to 4 months if exposed to temperatures between 34° to 40°F. It is best to use a mechanical seeder when planting to ensure consistent spacing and planting depth (1 ½ to 3 inch for peach seed) and increase germination uniformity. Rapid growth until June budding is desirable and can be achieved through proper irrigation, fertilization, and pest and disease management (LaRue, 1989). ‘Myrobalan’ seedling is grown for 2 years before summer budding occurs.