D. LINDGREN and C. C. YING

Application: The disadvantage (loss of average productivity) of using the same genetic material (origin) over a wide range is quantified. This disadvantage is also quantified for seed orchard crops, which have a composite origin. Thus the range of origins a seed orchard is recruited from can be analysed and optimised. The consequences of zone size can be quantified in breeding; for deployment of a provenance or deployment from a seed orchard. The number of seed sources needed to supply an area, like in consideration of a cost-effective nursery operation, can be quantitatively analysed.

Abstract. A conceptual model that considers the performance (adaptability) of a seed source (=an origin) and the location or range of its deployment is developed employing the Cauchy function. The model assumes that there exists an optimal site type for each provenance origin (genetic material), and that loss in performance is a function of the "distance" (a measure of increasing maladaptation) from the optimal site. The model requires the estimate of three parameters; a site requirement value that measures site type in one dimension; a measure of optimal performance; and a flexibility measure of the width of seed source adaptability. The Cauchy function has a known integral, thus the average adaptability over a range (a possible seed use zone) can be mathematically evaluated. The model was also extended to seed orchard crops representing progeny of parents of variable origins. Scots pine information in Sweden was used to exemplify possible applications of the model.

An EXCEL sheet on this site makes it possible to use some of the results of this study. It is available at: xxxx