Author
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Johnson, Richard |
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Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 8/1/2005 Publication Date: 9/13/2005 Citation: Johnson, R.C. 2005. Confining safflower pollen during regeneration of germplasm seed stocks. In: Workshop on the confinement of genetically engineered crops during field testing, September 13-15, 2004, USDA-APHIS Headquaters. Interpretive Summary: The Western Regional Plant Introduction Station (WRPIS) at Pullman, WA maintains the national collection of safflower (Carthamus tinctorius L.) germplasm, which currently includes more than 2300 accessions. Germplasm accessions received at genebanks usually require an initial seed increase or regeneration before the quantity and quality of seed is adequate for storage and distribution to users for research purposes. The factors important for regeneration of safflower at genebanks are also important in the potential use of safflower as a transgenic plant to produce pharmaceuticals and other proteins. These include pollination biology, outcrossing rates, outcrossing agents, potential to cross with wild relatives, and how pollen can be confined to prevent unwanted outcrossing. In this paper a review of these factors was completed to assist discussions and regulation policy for transgenic safflower. Technical Abstract: Seed regeneration of insect pollinated plant species requires an understanding of pollination biology, plant reproduction mode, outcrossing potential, and the species and behavior of pollinating insects. Safflower is normally self compatible and self pollinating. However, important natural outcrossing can occur at variable rates. A wide array of native and introduced insects can pollinate safflower but honey bees are the most common. Screen cages that eliminate the potential for pollination among accessions are effective for safflower seed regeneration. Normally, pollinators are not needed within the cages as safflower will naturally self-pollinate. However, in some cases the addition of pollinators is prescribed for producing seed of special genetic material or wild, self incompatible species. Outcrossing of safflower to wild relatives with the same number of chromosomes can be expected if grown in close proximity without cages. Caging on a field scale would be impractical. But large areas of New World locations could easily be found in which weedy safflower would be absent, eliminating the risk of gene flow between transgenic safflower and weedy relatives. |
