2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Traditional methods of developing and evaluating transgenic corn are resource and time-intensive. By removing small samples from corn kernels, researchers will be able to apply laboratory techniques to speed the trait identification and seed screening processes. The objective of this study was to determine the effect of sampling size and location on the germination rate of transgenic corn seeds. For each individual sampling size and location, 400 corn seeds were tested. Small drilling bits of varying diameters were used to remove seed tissue from each corn kernel. The pre-drilled and post-drilled corn weights allow the sample size to be determined. Both endosperm and germ samples were removed. The seeds were then germinated for seven days at a constant temperature of 25 C. If both the coleoptile and the radicle of the seedling measured over 1.2 cm in length, the seed was deemed as germinated. A significant disparity between sampling locations was observed. The germination rates between different locations within the germ varied between 59.0% and 13.3%. As expected, the susceptibility to germ sampling was higher than the susceptibility to endosperm. As the sampling size of germ tissue increased, the germination rate decreased. Germ sample sizes of 2.5 ± 0.4 mg resulted in germination rates below 44.5% versus a control of 87.0% for non-sampled seeds. The importance of this study is that for the first time a quantification of the amount of damage has made and its relationship to the germination rate has been established. Researchers can now use this information to determine the optimum sampling parameters that can minimize lethality of sampled corn seeds.