Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk|Scottish Crop Research Institute, Invergowrie, Dundee, UK. iain.milne@scri.ac.uk