Quality Control in the Development of Transgenic Crop Seed Products

Abstract

their plant products at various points in seed and food production (Beever and Kemp, 2000). Grain handlers In light of (i) public concern with the safety of genetically modified must develop the capability to evaluate the presence or crops, (ii) the issue of food labeling, and (iii) governmental regulation of transgenic plants, quality control (QC) monitoring of the process proportion of transgenic grain in truckloads and other of Transgenic Seed Product Development (TSPD) is essential to grain lots as nontransgenic grain takes on identity-preprotecting research investments, maintaining compliance with governserved status. Likewise, food processors need to effecmental regulations, and ensuring customer satisfaction. The primary tively monitor supply chains within identity preservation goal of QC monitoring in TSPD is to ensure the authenticity (transsystems to maintain compliance with the labeling regenic event identity and purity) of seed materials used in product quirements demanded by some markets. Furthermore, testing, in the development of regulatory data packages for governthe efficient evaluation of the type of any transgenic mental review, and to develop seed volumes for commercial release. grain present in supply chains is important to ensure Monitoring is performed to confirm the presence of the presumed compliance with governmental regulation. The auditing transgenic event(s) and the absence of all others. Sophisticated QC requirement actually begins with the seed companies, strategies formulated to monitor the product development process and to maintain quality standards in the manufacturing industry can which develop crop seed products for retail markets. serve as a foundation in devising efficient strategies tailored to meet Presently, seed certification requirements are expanding needs in the seed industry. A number of considerations in the design The Process of Transgenic SeedPublic concern with the safety of transgenic crops, Product Developmentthe issue of food labeling, as well as governmental regulation of transgenic plants by U.S. and internationalThe general process of TSPD encompasses a number agencies has spawned much debate over measures reof steps from transformation to new product launch, quired to assess genetic components of these plants and Abbreviations: BC1, generation resulting from the first backcross to the recurrent parent (BC2-BC6 follow the same convention with the specific generation designated)

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“…For example, over 1,300 initial transformation events were screened to identify the commercialized glyphosate-tolerant maize event NK603 (Heck et al, 2005). Events destined for commerce are thoroughly characterized for stable trait expression during breeding and are only advanced if the trait is stable over generations (Mumm and Walters, 2001). Molecular characterization of transgenic insertions is usually performed at early stages of event selection to remove those events with insertion arrangements (e.g.…”

“…Molecular characterization of transgenic insertions is usually performed at early stages of event selection to remove those events with insertion arrangements (e.g. inverted repeats) that could affect trait expression (Mumm and Walters, 2001). Thus, single events lacking stability are identified early and not moved forward for further analysis.…”

“…To further evaluate the phenotypic stability of a lead event in a seed-propagated crop, field trials are conducted following multiple rounds of self-pollination or backcrosses into elite varieties (Padgette et al, 1995;Mumm and Walters, 2001;Heck et al, 2005). Such evaluations further help to uncover any stability concerns with a particular event before commercialization.…”

“…In vegetatively propagated species and for species with long reproductive cycles, evaluation for stability in multiple environments or over multiple years serves a similar purpose. The breeding process further selects for events that are stably expressed irrespective of genetic background and of whether they are simple or complex loci (Mumm and Walters, 2001;Cellini et al, 2004). At the conclusion of the development process, a single event has been extensively evaluated for its phenotypic stability and, thus, for its genomic stability.…”

Chestnut

“…They are usually less expensive to produce than any of the clonal propagation methods, and if the transgenic plant can be crossed with wild-type trees and still express resistance, the resulting population can contain considerable genetic diversity. In annual crop species, the problem of introducing genetic diversity is dealt with by using a transgenic line as the nonrecurrent parent in a backcross breeding program (Mumm and Walters, 2001). In cotton, it can take as little as five years to move a transgene of interest from a single transformation event into a dozen or more elite varieties (Meredith, 2006).…”