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ARS Home » Pacific West Area » Davis, California » Nat'l Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes » Research » Publications at this Location » Publication #362293

Research Project: Managing Genetic Resources and Associated Information of Grape, Tree Fruit, Tree Nut, and Other Specialty Crops Adapted to Mediterranean Climates

Location: Nat'l Clonal Germplasm Rep - Tree Fruit & Nut Crops & Grapes

Title: Propagation from basal epicormic meristems remediates an agring-related disorder in almond clones

Author
item Gradziel, Thomas - University Of California
item Lampinen, Bruce - University Of California
item Preece, John

Submitted to: Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/7/2019
Publication Date: 4/11/2019
Citation: Gradziel, T., Lampinen, B., Preece, J.E. 2019. Propagation from basal epicormic meristems remediates an agring-related disorder in almond clones. Horticulturae. 5(28):1-9. doi:10.3390/horticulturae5020028.
DOI: https://doi.org/10.3390/horticulturae5020028

Interpretive Summary: The asexual propagation of clonal crops has allowed cultivation of superior selections for thousands of years. With time, clones deteriorate from genetic and epigenetic changes. Noninfectious Bud-Failure (NBF) in cultivated almond (Prunus dulcis) is a commercially important age-related disorder that results in the failure of new vegetative buds to grow in the spring, dieback of terminal shoots, witches-brooming of surviving buds, and deformed bark (roughbark) The incidence of NBF increases with clonal age, including within individual long-lived trees as well as nursery propagation lineages. It is not associated with any infectious disease agents. Consequently, traditional nursery practices emphasize the establishment of foundation-mother blocks using propagation-wood selected from well-established and monitored propagation-lineages. Commercial propagation utilizes axillary shoot buds through traditional budding or grafting. An alternative source of foundation stock is basal epicormic buds from individual trees of advanced age. The age-related progression of NBF appears to be arrested in such epicormic meristems, possibly owing to their unique origins and ontogeny. NBF development in commercial orchards propagated from Foundation-blocks established from these sources was dramatically suppressed over the 10 to 20 year expected commercial orchard-life. Foundation-stock stability can be further maintained through appropriate management of propagation source-trees, which requires accurate knowledge of meristem origin and development.

Technical Abstract: The asexual propagation of clonal crops has allowed cultivation of superior selections for thousands of years. With time, clones deteriorate from genetic and epigenetic changes. Noninfectious Bud-Failure (NBF) in cultivated almond (Prunus dulcis) is a commercially important age-related disorder that results in the failure of new vegetative buds to grow in the spring, dieback of terminal shoots, witches-brooming of surviving buds, and deformed bark (roughbark) The incidence of NBF increases with clonal age, including within individual long-lived trees as well as nursery propagation lineages. It is not associated with any infectious disease agents. Consequently, traditional nursery practices emphasize the establishment of foundation-mother blocks using propagation-wood selected from well-established and monitored propagation-lineages. Commercial propagation utilizes axillary shoot buds through traditional budding or grafting. An alternative source of foundation stock is basal epicormic buds from individual trees of advanced age. The age-related progression of NBF appears to be arrested in such epicormic meristems, possibly owing to their unique origins and ontogeny. NBF development in commercial orchards propagated from Foundation-blocks established from these sources was dramatically suppressed over the 10 to 20 year expected commercial orchard-life. Foundation-stock stability can be further maintained through appropriate management of propagation source-trees, which requires accurate knowledge of meristem origin and development.