Pollen longevity, flowering phenology, and seedbank persistence of Camelina sativa (L.) Crantz and congenic species

The potential for wide-scale adoption of genetically engineered (GE) Camelina sativa (L.) Crantz in North America has raised ecological concerns of gene flow to its weedy relatives. The objectives of this study were to determine the pollen longevity, flowering phenology and seedbank persistence of C. sativa and congenic species. Percent pollen germination of all Camelina species was reduced with increasing temperature and exposure time. Pollen germination was not observed for all taxa after 72 h between 20-40 degrees C. Weather conditions had a significant effect on pollen longevity. Under cloudy conditions, all taxa pollen had a longer period of longevity (half-life: 0.6-0.8 h) than sunny conditions (0.3-0.4 h). Under both conditions, C. sativa, Camelina alyssum (Mill.) Thell., and Camelina microcarpa Andrz. Ex DC. pollen had a longer period of longevity than Camelina hispida var. grandiflora (Boiss.) Hedge, Camelina laxa C. A. Mey, and Camelina rumelica Velen., but pollen germination was not observed after 5 h exposure. The flowering phenology of C. sativa, C. microcarpa, and C. alyssum behaved similarly, which was different from C. hispida, C. laxa, and C. rumelica. Flowering synchrony among taxa was observed, facilitating pollen-mediated gene flow among taxa. Seeds of C. sativa, C. alyssum, and C. microcarpa did not exhibit dormancy in the soil, but the germination ability of C. sativa throughout the growing season raises the ecological concerns of gene flow from C. sativa volunteers. This new information on pollen longevity, flowering phenology, and seedbank persistence will be helpful for creating containment and coexistence strategies between GE and Non-GE C. sativa, isolating field trials, and managing GE C. sativa volunteers associated weed problems.