The biology and ecology of hexaploid wheat (Triticum aestivum L.) and its implications for trait confinement

This review summarizes the biological and ecological factors of hexaploid wheat (Triticum aestivum L.) that contribute to trait movement including the ability to volunteer, germination and establishment characteristics, breeding system, pollen movement, and hybridization potential. Although wheat has a short-lived seedbank with a wide range of temperature and moisture requirements for germination and no evidence of secondary dormancy, volunteer wheat populations are increasing in relative abundance and some level of seed persistence in the soil has been observed. Hexaploid wheat is predominantly self-pollinating with cleistogamous flowers and pollen viability under optimal conditions of only 0.5 h, yet observations indicate that pollen-mediated gene flow can and will occur at distances up to 3 km and is highly dependent on prevailing wind patterns. Hybridization with wild relatives such as A. cylindrica Host., Secale cereale L., and Triticum turgidum L. is a serious concern in regions where these species grow in field margins and unmanaged lands, regardless of which genome the transgene is located on. More research is needed to determine the long-term population dynamics of volunteer wheat populations before conclusions can be drawn with regard to their role in trait movement. Seed movement has the potential to create adventitious presence (AP) on a larger scale than pollen, and studies tracing the movement of wheat seed in the grain handling system are needed. Finally, the development of mechanistic models that predict landscape-level trait movement are required to identify transgene escape routes and critical points for gene containment in various cropping systems. Key words: Triticum, coexistence, gene flow, genetically-engineered, herbicide-resistant, trait confinement

The potential benefits, risks and costs of genetic use restriction technologies

Genetic use restriction technologies (GURTs) are designed to restrict access to genetic materials and their associated phenotypic traits. Originally GURTs were developed to ensure that new crop varieties could be protected against unauthorized use, but recently there has been interest in the use of GURTs to facilitate novel trait confinement. There is controversy over the potential use of GURTs in food and feed plant varieties. Considerable discourse exists amongst many groups representing both public and private, and government and non-government interests, about whether GURTs should be adopted based on the potential benefits versus the potential risks and costs. Potential benefits include intellectual property rights protection, stimulation of private crop breeding research and development, enhancement of genetic diversity in breeding programs, and novel trait confinement. Potential risks and costs associated with GURTs include intra- and interspecific escape of the technology, reduced access and increased cost of genetic material for breeders, increased regulation, liability risks in the event of GURT failure or escape, increased seed costs for farmers, further limits on access to novel genetic material for farmers, greater industrial control over agriculture, and a further decrease in agro-biodiversity. Although topical and controversial, the potential benefits versus the potential risks and costs of implementing GURTs are difficult to adequately assess because they are in the developmental stage and there has been no known field-based testing to-date. Until the results of peer-reviewed research on the environmental, social, economic and political impacts of GURTs are publicly available, no fair and useful assessment for the commercial release of the technology can occur. Key words: Genetic use restriction technology, plants with novel traits, genetically modified, genetically engineered, plant breeding