Facilitating co-existence by tracking gene dispersal in conventional potato systems with microsatellite markers

Abstract

Based on international findings, Irish co-existence guidelines for the cultivation of GM potato stipulate that an isolation distance of 20 m is required to minimize the spread of transgenic pollen in accordance with required labeling thresholds. As potato tolerant to Phytophthora infestans is the most applicable GM crop from an Irish context, we tested the efficacy of this isolation distance under Irish environmental conditions using the conventional variety Désirée as a pollen donor and the male-sterile variety British Queen as a pollen receptor. Gene flow was determined by scoring for berry presence on receptor plants and confirmed using a microsatellite marker system designed to assess paternity in F 1 seedlings. 99.1% of seedlings recovered were identified as having Désirée paternity. Whereas 19.9% (140/708) of total berries formed on receptor plants occurred at a distance of 21 m from the pollen source, only 4 of these berries bore viable true potato seed (TPS), from which 23 TPS germinated. TPS-bearing berry formation was negatively correlated with distance from the pollen source, and although overall distribution of berries and seeds was non-random across the plot, no significant correlation was evident with respect to wind direction. Microsatellite markers were also used to confirm that the foraging beetle Meligethes aeneus is a vector for the transmission of potato pollen, but a more detailed statistical analysis of this dataset was limited by inclement weather during the trial. To conclude, we recommend that a two-tiered system be established in regard to establishing isolation distances for the experimental trial and commercial cultivation of GM potato in Ireland, and that responsible crop management be adopted to minimize the establishment of TPS-derived volunteers, which we have noted will emerge through a rotation as a result of pollen-mediated gene flow.

Gene Flow between Potato Cultivars under Experimental Field Conditions in Argentina

“…In these experiments, the pollen donors (transgenic cultivars) were Desirée (McPartlan and Dale 1994;Skogsmyr 1994), Iwa (Tynan et al 1990;Conner and Dale 1996), and Rua and Ilam Hardy (Conner and Dale 1996), and the pollen receptors (non-transgenic cultivars) were Iwa (Tynan et al 1990), a mixture of breeding lines (Conner and Dale 1996), Desirée (McPartlan and Dale 1994), and Stina (Skogsmyr 1994). Also, gene flow experiments have been carried out but with non-transgenic cultivars (Desirée and British Queen) (Petti et al 2007). The results were very variable regarding the formation of hybrid seeds in the various field experiments: from a long distance (1,000 m) from the pollen donor with the larger percentage (72%) in the near vicinity (Skogsmyr 1994) to short distances up to 9 m (Tynan et al 1990), 10 m (Conner and Dale 1996;McPartlan and Dale 1994), and 21 m (Petti et al 2007), but at very low rates.…”

Successful pollen dispersal modulates with flowering phase in field-hybridizing grasses

“…The shifts in affinity for the different dispersal models (Table 1, Figure 3) reflects the slightly higher proportion of long-distance pollination events observed as anthesis progresses, a pattern which the composite model is by design sensitive to (because it incorporates the inverse power expression, Figure 3B). These and other decline models are evident for many different species, independently, in gross measures of pollen distribution during flowering ( Lavigne et al 1998;Ma et al 2004;Shaw et al 2006;Petti et al 2007;Beckie and Hall 2008;Matter et al 2013). In the case of the more detailed time-series data presented here, what is distinct is that the successful pollen distribution pattern changes over the course of flowering maturity in the donor populations, with altering affinity for the different dispersal models as donor pollen production declines.…”

Successful pollen dispersal modulates with flowering phase in field-hybridizing grasses

“…The shifts in affinity for the different dispersal models (Table 1, Figure 3) reflects the slightly higher proportion of long-distance pollination events observed as anthesis progresses, a pattern which the composite model is by design sensitive to (because it incorporates the inverse power expression, Figure 3B). These and other decline models are evident for many different species, independently, in gross measures of pollen distribution during flowering ( Lavigne et al 1998;Ma et al 2004;Shaw et al 2006;Petti et al 2007;Beckie and Hall 2008;Matter et al 2013). In the case of the more detailed time-series data presented here, what is distinct is that the successful pollen distribution pattern changes over the course of flowering maturity in the donor populations, with altering affinity for the different dispersal models as donor pollen production declines.…”