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Authors: | G.A. Lang, J.W. Olmstead, M.D. Whiting |
Keywords: | Prunus avium, rootstocks, source-sink relationships, spur extinction, balanced pruning, leaf-to-fruit ratio |
DOI: | 10.17660/ActaHortic.2004.636.74 |
Abstract:
In nature, sweet cherry (Prunus avium L.) is a large (15+ m) tree; under orchard management, canopy volume and stature are reduced by pruning, thereby altering leaf and fruit distribution and source:sink relationships such that fruit quality is generally enhanced. New rootstocks, such as Gisela 5, exhibit a tendency to increase total floral bud formation, thereby altering fruit and leaf distribution and source:sink relationships in a manner that often reduces fruit quality. To quantify these opposing influences and better predict the long-term effects of novel management strategies for sweet cherry production, we are developing a dynamic seasonal growth model.
This model includes the following fruiting (sink) components: 1) spur-borne, usually multiple, fruiting buds on 2-year and older wood (Fspur) plus 2) single fruiting buds on 1-year-old wood (Fshoot); vegetative sink components: 1) expanding leaves (Lexp), 2) new lateral shoots (Slat), 3) new terminal shoots (Sterm), 4) new roots (Rnew), and 5) total branch+trunk+root storage reserves (SRCtotal); and photosynthate source components: 1) leaf area of fruiting spurs (LAspur/f), 2) leaf area of non-fruiting spurs (LAspur/nf), 3) leaf area of new terminal shoots (LAterm), 4) leaf area of new lateral shoots (LAlat), 5) storage reserves within the branch (SRlocal), and 6) storage reserves beyond the immediate branch (SRdistal). The dynamic relationships between these components are being modeled empirically for key developmental stages to illustrate theoretical growth of a sweet cherry branch and tree via interactive computer graphics.
The implications of these model relationships for predicted performance over time, as young sweet cherry trees fill their orchard space and branches age under the imposition of several canopy and crop management strategies, are discussed.
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