1. The largest collection in Europe of data on gene flow and persistence has been organized.
SIGMEA collated and synthesized experimental data on gene flow and filled gaps in knowledge by designing and conducting further evaluations, particularly at the landscape-scale or over several years of cropping sequence. Maize and oilseed rape were the major crops targeted for this study - other crops under consideration were sugar beet, rice and wheat. Available information from past and current field studies on cross pollination, volunteers, ferals and wild relatives were gathered from 22 SIGMEA partners through a rigorous procedure which ensured quality control through electronic submission of data sets using a standard template or ‘data-entry format’, thorough checking and retrieval of any missing information, internal review of each data set, and a formal mechanism for completing and ‘signing off’ data sets. The data were made available to other users within SIGMEA through a secure web server.
The synergies within the project led new research studies, using harmonised protocols, on moderate- to long-distance gene flow, plant demography and characterising volunteer, feral and wild populations. Thanks to those studies that arose within the SIGMEA project, the collated database was significantly enhanced. By the end of the SIGMEA project, the database had over 100 data sets (Fig. 1), constituting more than 150 “experiment-years”. Around two thirds of the data involve oilseed rape or close relatives. Information for beet and maize comprised just less than one sixth each. A few data sets were submitted on wheat and rice. Data on crops and volunteers constitute around 35% each, wild relatives 16% and ferals 6%. However, there is little data on ecological impacts — as distinct from gene flow by seed and pollen. Formal submissions from this field study involve Bt maize in Spain and herbicide tolerant oilseed rape.
Due to the very high replication achieved by combining data from different sites, the crop-specific conclusions in SIGMEA on cross pollination and seed persistence in maize and oilseed rape are mostly of very high statistical significance and make it possible to draw general conclusions about given topics. Most of the data sets provide information on scale, climate, geography, biology, as well as spatial and temporal factors associated with pollen flow, cross pollination and seed dynamics, in more detail than appears in refereed publications. The data sets have been extensively used to provide added value through meta-analysis, data mining and the development and verification of gene flow models designed within SIGMEA. Additionally, the database allowed an assessment of three questions about transferability of information: the consistency of measurements at different spatial (or temporal) scales; the differences between agricultural regions in Europe with different climates and soils; and the behaviour of different crop species.
Since much of the research is still not in the public domain, the data sets are presently accessible only within SIGMEA to partners who submitted data, and to others with designated access.
In summary, the SIGMEA database, together with already published information, provided a sound basis to investigate maize, oilseed rape and beet, and draw the conclusions as summarised below.
Figure 1. Location of main experimental studies available in the SIGMEA database on maize (red), oilseed rape (yellow) and beet (blue). Some locations involved several experiments.
