Notes from the Germination & Early Growth one-day meeting

Friday October 27, 2006,

Venue : Research Centre Flakkebjerg, Danish Institute of Agricultural Sciences.

Dear all

Thank you all for contributing to our working group meeting on Friday 27^th.  I hope you had an enjoyable day hearing about the common experiment and sharing our recent research activities.  I have made some very brief notes from the meeting as a memory aid to what we discussed and agreed: 

1. All agreed to initiate a follow up experiment (based on the same general protocol) autumn 2007. Participants can continue to record emergence from the existing “pots” if they wish to, but it is not compulsory.  Lars and Jack are to join in the autumn 2007 common experiment.
2. Some striking differences between the local and common seed lot emergence behaviour (and indeed seed size) were noted between the sites, suggesting some environmental adaptation of the local seed lots.   This was particularly true for the Mediterranean participants (the northern locations showed a more similar response to the common seed lot).   All participants agreed it would be an interesting idea to sow some of the common seed during 2007 and raise the individuals through to maturity in their local environment.  The idea would be to raise plants from the common genetic origin (i.e. the Danish population) and identify whether the seeds they produce (under local environmental conditions) differed in their emergence, early growth when subsequently grown in 2008 in a common environment (probably Andrea/Paul in the UK).  It would also be interesting to see whether the seed size was the same or differed between the participating sites.  This simple sub-experiment would enable the possible impact of the maternal environment on seed characteristics and emergence behaviour to be “separated” out from genetically inherent characteristics of the common Danish population. Andrea, Jack & Paul agreed to prepare a simple protocol for sowing the common seed and seed harvesting for 2007.   Some considerations  when preparing this protocol will be to
   1. keep the plant raising very simple and low maintenance for all participants
   2. agree the number and spacing of plants raised and harvested for seed collection to avoid the sample set being based on too few individuals
   3. agree a simple procedure for harvesting and post harvest cleaning of the seed prior to sending to the UK
   4. identify the simple experiment for the UK and the most important attributes that should be recorded.

3. Andrea to ask Alistair whether he has any data on variation in seed size from the different participating locations from the 2005 seed.
4. Ilse, Adam & Andrea agreed to work on preparing a modified protocol for distribution and discussion prior to the next EWRS meeting in Hammer.  Several practical issues and questions were raised by participants and are summarised below. These will need to be addressed in the new protocol:

1. Day degrees for soil disturbance should be based on air and not soil temperature data.
2. Only 1000 seed should be buried in each “pot”.
3. A point for discussion - would it be possible to use local substrate, rather than try and make up a substrate common to all sites? This could avoid problems experienced at some sites where the suggested common substrate appeared to be unsuitable and experienced “capping” in 2006.  However local substrate would have an existing seed bank.  Therefore, a local substrate would either need to be sterilised to kill any existing weed seeds or background counts would need to be made and extracted from the emergence in the experimental pots.  If the substrate was not sterilised then the substrate would need to be extremely well mixed so that the background seeds could be assumed to be evenly distributed.  It would also require additional counting at each recording occasion to be made to obtain the background emergence.
4. It was agreed that we should no longer use the glass plate as it appears to dry out soil and doesn’t help very much in determining the timing of the initial soil disturbance event
5. When counting “white threads” at disturbance times remember to count them separately from the total emergence.
6. The frequency of recording at disturbance times probably needs to be as frequent as every 2 to 3 days (i.e. not to include them in the seedling emergence count made at that time).
7. The sieve size appeared to be inappropriate for several of the sites and a new protocol for both preparing soil at the start of the experiment and at the disturbance times needs to be addressed.
8. Very few sites participated in the assessment of the plant size so it was agreed to drop this option for next time.
9. Many of the sites showed lower emergence from the local compared with the common seed lots and it was suggested this could be variation in seed handling/after-ripening confounding the results.  To avoid possible differences in after-ripening between common and local seed lots, it was agreed to bury seeds as soon after harvesting as possible rather than trying to co-ordinate burial across all sites at the same time.  This would enable seeds to be sown at a time more appropriate to the natural timing of shedding and burial at each local site.
10. Adam agreed to send everyone simple trays made from a non-wicking material that can be used by all as the liner for each “pot” instead of the material currently being used.

5. All agreed that it would be a good idea to submit a poster to the forthcoming 2007 EWRS symposium at Hammer regarding the preliminary findings of the first year of the common experiment. Andrea agreed to co-ordinate a draft poster for circulation and comment and also to submit a short abstract to the symposium so that it can be allocated to a session as soon as possible.  All agreed that Ilse Rasmussen should be first author of the poster as recognition for her hard work preparing and co-ordinating the protocol.  All other participants will be listed by alphabetical order thereafter.
6. Jack, Andrew and Ilse agreed to spend some time prior to Hammer 2007 analysing the data.   However, all participants are encouraged to have a look at/analyse the data (distributed in this e-mail) as they wish prior to the meeting at Hammer.  Some suggestions include a) plotting data as proportions for all sites instead of actual numbers, b) plotting emergence as actual numbers on each sampling occasions and not just cumulative emergence as this will enable small flushes to be identified more easily.  All agreed that any publication of data from the common experiment outside the working group should be properly acknowledged to the EWRS working group participants.
7. The next working group meeting will be held at the EWRS symposium in Hammer, Norway in June 2007.  This will only be a short meeting, but the primary aim will be to agree on the amended protocol for the following autumn and discuss the preliminary analysis.
8. The next full working group workshop will be held during autumn 2008 to review the second year’s data from the common experiment.  Date and venue to be discussed at Hammer 2007.

9. Finally a “BIG THANK YOU”  to Ilse Rasmussen for preparing the common protocol, answering many questions during 2005/6 and for hosting the working group so well last week!!!

 Best wishes!

Andrea Grundy,  31 October 2006

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