1. Project Nr. 2009/0218/1DP/1.1.1.2.0/09/APIA/VIAA/099 Cereal breeding for organic farming: crop traits related with competitiveness against weeds Dace Piliksere State Priekuli Plant Breeding Institute Conference "Diversity in Plant Breeding and Agriculture: Strategies for Healthy Lifestyle" Stende, 31.05.2012

2. Assessing weed suppression ability of crops has become more important with the development of organic plant breeding. This report introduces with first two year (2009/2010 and 20101/2011) results of field experiments in the project “Development, improvement and implementation of environmentally friendly and sustainable crop breeding technologies” (2009/0218/1DP/1.1.1.2.0/09/APIA/VIAA/099). Introduction The aim is to develop the methodology for an estimation of cereal varieties and breeding lines for their competitive capacity against weeds, to establish more effective criteria of the selection by significant crop characteristics in the breeding process for organic growing conditions.

3. The investigation is carried out with spring barley, spring oat, winter triticale and winter wheat varieties and breeding lines in organic crop rotations at State Priekuli Plant Breeding Institute and at State Stende Cereals Breeding Institute in Latvia. Harrowing is not performed in the trials, to exclude the impact of this factor. Different observations:  plant density after emergence,  growth habit at tillering and at stem elongation,  tillering capacity,  plant height at the beginning and at the end of stem elongation and before the harvesting,  crop plant development rate in terms of days from sowing to such phenological phases as germination (emergence), tillering, stem elongation, heading and fully ripening,  amount of crop yield, – are taken into account to evaluate crop ability to suppress weed growth in terms of weed ground cover several times in the growing season. Linear correlation method is used for statistical data analysis. Material and Methods

4. Results and Discussion

8. Two year investigation results show both some similar correlations, and some inconsistent correlations between different crop and weed traits. Therefore field experiments should be carried out at least one more year to examine observed correlations. Detection of the most important crop characteristics, which provide the competitiveness against weeds in cereals, is stressed as a desired result. Conclusion

9. Acknowledgements For great amount of data collecting as well as for suggestions for further work: Vija Strazdina, Zaiga Vicupe, Zaiga Jansone - State Stende Cereals Breeding institute Linda Legzdina, Indra Beinarovica, Arta Kronberga - State Priekuli Plant Breeding Institute This study was performed with financial support of European Social Fund co-financed project 2009/0218/1DP/1.1.1.2.0/09/APIA/VIAA/099 Thank you for your attention!