Since all conifers are wind pollinated, orchards located within the natural range of the species are susceptible to non-orchard sources of pollen (contamination). Contaminate pollen is considered to have a negative effect on both the orchard?s estimated genetic worth of the improved trait (for example growth) and the adaptive potential of seed orchard progeny. Our current protocol for assessing the contribution of pollen contamination uses pollen monitoring technique. Both the period of pollen shed and the density of pollen clouds for both orchard and non-orchard sources are measured. Depending on the orchard site, the genetic worth of a specific orchard parent is reduced by the proportion of total contaminate pollen to orchard pollen. The species selected for this study is coastal Douglas-fir since most of the orchards are located on eastern Vancouver Island. The assumption made with the current protocol for estimating the gamete contribution of contaminate pollen is that contaminate pollen is related to its calculated proportion in the orchard pollen cloud as measured by pollen monitoring technique. Until recently, we had no better way to assess pollen contamination. Now paternity analyses, using molecular technique has been successfully developed for seed orchard applications. While it is possible to identify both orchard and non-orchard sources of pollen parents using DNA fingerprinting, it is unlikely we will adopt this new technique for routine gamete contribution. It will, however, allow us to assess the accuracy of our current pollen monitoring technique and provide orchard managers with confidence that the annual calculations of a seed lot?s genetic worth are reliable. Furthermore, since a seedlot?s genetic worth is now incorporated directly into timber supply analysis, future estimates of wood production will also be more reliable.
Joe Webber and Michael Stoehr.
Webber, Joe E., Stoehr, Michael U.. 2006. Evaluating the protocol for quantifying pollen contamination on the genetic worth of conifer seed orchards. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR292