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Working Group Meetings

Wageningen 2002

Germination & Early Growth Working Group meeting

24 June 2002, Papendal, The Netherlands

 

  1. The current joint experiment. A summary was presented of the preliminary results from the first three years of joint experimentation. Main points from the research study so far have been:
  1. Evidence of synchrony in emergence (particularly the spring flush) of seedlings of all seed sources at any given burial site. This is potentially encouraging regarding the potential to predict emergence from different populations at a given site using the same model.
  2. The magnitude of the spring flush of Chenopodium album would appear to be related to the winter temperatures. An inverse relationship has been observed between the mean winter temperature and the magnitude of the spring flush (i.e. the cooler the mean winter temperature the greater the subsequent flush of emergence). The same cannot be said of Stellaria media where a more complex maternal ripening environment x burial environment interaction is likely.
  3. There is an interesting observation in the behaviour of the Stellaria media and Chenopodium album seed matured in Italy in 2000. These seeds give rise to a significantly greater flush of emergence than the seed collected in 1999 and seed from all other provenance’s suggesting that there may be something related to the ripening conditions during 2000 that confer a greater emergence ability of the seeds produced at that site during that particular year. Such patters in behaviour raise interesting questions and may help give some clues to the influence of the ripening environment on subsequent seed quality.
  4. Some success regarding modelling the emergence data from the 8 participating burial sites. See abstract in proceedings for further details.
  5. The results will be submitted as a refereed paper to Weed Research shortly.
  1. Future Experiment:
    2.
  1. Ideas were discussed for a future collaborative experiment that will focus on early growth. The proposed start date will be autumn 2003. The working group will have an opportunity to meet prior to the start of the collaborative experiment to discuss final details of the protocol at the next scheduled working group meeting which will be held direct after the AAB/EWRS conference on weed seedbanks September 2003.
  2. It was decided at the meeting that we should set a question that we can address (as with the previous experiment, which will come to a close spring 2003). This question would add focus and purpose to the study. It was also agreed that the study should build on the most of the unique resource of the group i.e. the access to different seed provenance’s and growing localities to produce a diverse data set.
  3. A suggested objective of the study could be:

The time between the germination of a seed and emergence at the soil surface (the post-germination, pre-emergence growth phase) is a precarious time during a seedlings development. It has been suggested, but little quantified, that this stage in development before a seedling becomes no longer dependant on its seed resource, accounts for a substantial proportion of loss of viable seeds from the seedbank. It also represents a vulnerable time during which weed control strategies, such a mechanical weed control may be particularly effective. How variable is this pre- emergence growth phase between different populations of a given species? How might this growth-phase differ under different climatic conditions? By identifying sources of variability, might we be able to minimise variability and target this vulnerable stage in development for more efficient weed control?

 

  1. Considerations for methodology:
bulletThe study needs to be simple and not time consuming.
bulletSuch an early growth study would be relatively quick to complete.
bulletCould the study use pre-germinated seeds?
bulletShould we use a range of different burial depths (perhaps 4 depths)?
bulletHow many different populations (perhaps one or two species that can be pre-germinated relatively simply…e.g. C. album and S. media?).
bulletHow much should we standardise? Should the study make use of the different soil types at the different sites, or use a standardised substrate? Should the substrate in the pots have a standard compaction and moisture?
bulletWhat is the relative importance of population variability vs. seedbed variability? This will ultimately decide what to standardise and determine any final protocol for the study.

 

  1. Conference in 2003:

 

  1. The members of the working group aim to meet again in September 2003. The next major target for the working group is to organise this meeting, in collaboration with the Association of Applied Biologists, an international conference on seedbanks. The need for a focussed 2-day conference specifically on weed seedbanks, germination and early growth has been previously agreed by the working group members. The intention is for it to follow a similar format to the AAB Seedbanks meeting held in Oxford, March 1998 (i.e. with a programme of offered and invited papers/posters and the publication of a proceedings).
  2. So far a date and venue have been confirmed and approval has been granted by the AAB for the publication of proceedings to accompany the conference. The first 2 days will be an open conference aiming at approx. 70 delegates on the 17 & 18th September 2003 at the University of Reading, UK.
  3. The smaller and more discussion-based EWRS working group workshop, will continue at Reading University directly after the close of the conference for a further 2 days (Friday 19th and Saturday 20 September 2003). The EWRS working group workshop will take the usual format that has been adopted in previous years (informal discussion around the joint experimentation and planning of future activities).
  4. It is proposed that we hold a half day visit on the Friday morning (19th) to those interested to stay on for the EWRS working group workshop (and booked in advance to pre-determine numbers for host) to a local site of "seed interest". (contact Martin Parham at Herbiseed regarding the logistics of this).
  5. The full allocated EWRS working group budget in 2003 will be dedicated to ensuring that as many working group members are able to attend the working group meeting. In return, working group members (Alistair Murdoch, Renée Bekker, Jon Marshall, Naomi Jones and Frank Forcella) have offered to provide editorial and session chairing responsibilities for the 2-day conference.
  6. A request for Overseas invited speaker funds have been requested from the AAB towards inviting a key speaker(s) to the conference (to be finalised).
  7. The AAB have agreed to organise the entire domestic, conference-related arrangements and publication of the conference proceedings. The working group workshop that follows on from the conference will be kindly hosted by a working group member, Dr Alistair Murdoch of Reading University.
  8. At the Papendal meeting the proposed content of the conference was discussed and additional items highlighted which have now been includes on the first call for papers. The closing date for provisional offers of papers will be the 1 November 2002. A first call for papers will be sent out shortly by the AAB to AAB members. The Working Group web page will also have further information including downloadable forms relating to the conference. This information will also be sent out to other working group co-ordinators to pass onto their membership and other appropriate mailing lists.
  9. The EWRS logo etc. will appear on all printed material relating to the conference and it will be advertised as a collaborative event between the EWRS & AAB.

 

 

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